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Appendix A to GM 21.A.101 Classification of design changes

Available versions for ERULES-1963177438-3715

ED Decision 2017/024/R found in: Initial Airworthiness and Environmental Protection (No 748/2012) Part-21 Part-21L (Jul 2024)

Version Text

Appendix A to GM 21.A.101 Classification of design changes

ED Decision 2017/024/R

The following tables of ‘substantial’,
‘significant’, and ‘not significant’ changes are adopted by the FAA, Agência
Nacional de Aviação Civil (ANAC), the European Aviation Safety Agency (EASA),
and Transport Canada Civil Aviation (TCCA) through international
collaboration. The classification may change due to cumulative effects and/or
combinations of individual changes.

A.1    Examples of Substantial, Significant, and
Not Significant Changes for Small Aeroplanes
(CS-23).

A.1.1  Table
A-1 contains examples of changes that are ‘substantial’ for small aeroplanes
(CS-23).

Table
A-1. Examples of Substantial Changes for Small Aeroplanes (CS-23)

<table border="1" cellpadding="0" cellspacing="0" width="605">
<tr>
<td width="52">
Example
</td>
<td width="261">
Description of Change
</td>
<td width="292">
Notes
</td>
</tr>
<tr>
<td width="52">
1.
</td>
<td width="261">
Change to wing location (tandem, forward, canard,
 high/low).
</td>
<td width="292">
Proposed change to design is so extensive that a
 substantially complete investigation of compliance with the applicable
 certification basis is required.
</td>
</tr>
<tr>
<td width="52">
2.
</td>
<td width="261">
Fixed wing to tilt wing.
</td>
<td width="292">
Proposed change to design is so extensive that a
 substantially complete investigation of compliance with the applicable
 certification basis is required.
</td>
</tr>
<tr>
<td width="52">
3.
</td>
<td width="261">
A change to the number of engines.
</td>
<td width="292">
Proposed change to design is so extensive that a
 substantially complete investigation of compliance with the applicable
 certification basis is required.
</td>
</tr>
<tr>
<td width="52">
4.
</td>
<td width="261">
Replacement of piston or turboprop engines with turbojet
 or turbofan engines.
</td>
<td width="292">
Proposed change to design is so extensive that a
 substantially complete investigation of compliance with the applicable
 certification basis is required.
</td>
</tr>
<tr>
<td width="52">
5.
</td>
<td width="261">
Change to engine configuration (tractor/pusher).
</td>
<td width="292">
Proposed change to design is so extensive that a
 substantially complete investigation of compliance with the applicable
 certification basis is required.
</td>
</tr>
<tr>
<td width="52">
6.
</td>
<td width="261">
Increase from subsonic to supersonic flight regime.
</td>
<td width="292">
</td>
</tr>
<tr>
<td width="52">
7.
</td>
<td width="261">
Change from an all-metal to all-composite aeroplane.
</td>
<td width="292">
Proposed change to design is so
 extensive that a substantially complete investigation of compliance with the
 applicable certification basis is required.
</td>
</tr>
<tr>
<td width="52">
8.
</td>
<td width="261">
Certifying a CS-23 (or predecessor basis, such as JAR-23)
 aeroplane into another certification category, such as CS-25.
</td>
<td width="292">
—
</td>
</tr>
</table>

A.1.2     Table A-2 contains examples of changes
that are ‘significant’ for small aeroplanes (CS-23).

<table border="1" cellpadding="0" cellspacing="0" width="605">
<thead>
<tr>
<td colspan="6" width="605">
Table A-2. Examples of
 Significant Changes for Small Aeroplanes (CS-23)
</td>
</tr>
<tr>
<td width="52">
Example
</td>
<td width="128">
Description of change
</td>
<td width="88">
Is there a change to the general configuration?
 21.A.101(b)(1)(i)
</td>
<td width="88">
Is there a change to the principles of
 construction? 21.A.101(b)(1)(i)
</td>
<td width="93">
Have the assumptions used for certification
 been invalidated? 21.A.101(b)(1)(ii)
</td>
<td width="156">
Notes
</td>
</tr>
</thead>
<tr>
<td valign="top" width="52">
1.
</td>
<td valign="top" width="128">
Conventional tail to T-tail or
 V-tail, or vice versa.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Change to general
 configuration. Requires extensive, structural flying qualities and
 performance reinvestigation. Requires new aeroplane flight manual (AFM) to
 address performance and flight characteristics.
</td>
</tr>
<tr>
<td valign="top" width="52">
2.
</td>
<td valign="top" width="128">
Changes to wing configuration,
 such as change to dihedral, changes to wing span, flap or aileron span,
 addition of winglets, or increase of more than 10 per cent of the original
 wing sweep at the quarter chord.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Change to general
 configuration. Likely requires extensive changes to wing structure. Requires
 new AFM to address performance and flight characteristics. Note: Small
 changes to the wingtip or winglet are not significant changes. See table for
 ‘not significant’ changes.
</td>
</tr>
<tr>
<td valign="top" width="52">
3.
</td>
<td valign="top" width="128">
Changes to tail configuration,
 such as the addition of tail strakes or angle of incidence of the tail.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Change to general
 configuration. Likely requires extensive changes to tail structure. Requires
 new AFM to address performance and flight characteristics.
Note: Small changes to tail are
 not significant changes.
</td>
</tr>
<tr>
<td valign="top" width="52">
4.
</td>
<td valign="top" width="128">
Tricycle/tail wheel
 undercarriage change or addition of floats.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Change to general
 configuration. Likely, at aeroplane level, general configuration and
 certification assumptions remain valid.
</td>
</tr>
<tr>
<td valign="top" width="52">
5.
</td>
<td valign="top" width="128">
Passenger-to-freighter
 configuration conversion that involves the introduction of a cargo door or
 an increase in floor loading of more than 20 per cent, or provision for
 carriage of passengers and freight together.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Change to general configuration
 affecting load paths, aeroelastic characteristics, aircraft-related systems,
 etc. Change to design assumptions.
</td>
</tr>
<tr>
<td valign="top" width="52">
6.
</td>
<td valign="top" width="128">
Replace reciprocating engines
 with the same number of turbo-propeller engines.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Requires extensive changes to
 airframe structure, addition of aircraft systems, and new AFM to address
 performance and flight characteristics.
</td>
</tr>
<tr>
<td valign="top" width="52">
7.
</td>
<td valign="top" width="128">
Addition of a turbo-charger
 that changes the power envelope, operating range, or limitations.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Invalidates certification
 assumptions due to changes to operating envelope and limitations. Requires
 new AFM to address performance and flight characteristics.
</td>
</tr>
<tr>
<td valign="top" width="52">
8.
</td>
<td valign="top" width="128">
The replacement of an engine of
 higher rated power or increase thrust would be considered significant if it
 would invalidate the existing substantiation, or would change the primary
 structure, aerodynamics, or operating envelope sufficiently to invalidate
 the assumptions of certification.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Invalidates certification
 assumptions. Requires new AFM to address performance and flight
 characteristics. Likely changes to primary structure. Requires extensive
 construction reinvestigation.
</td>
</tr>
<tr>
<td valign="top" width="52">
9.
</td>
<td valign="top" width="128">
A change to the type of
 material, such as composites in place of metal, or one composite fibre
 material system with another (e.g. carbon for fiberglass), for primary
 structure would normally be assessed as a significant change.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Change to principles of construction
 and design from conventional practices. Likely change to
 design/certification assumptions.
</td>
</tr>
<tr>
<td valign="top" width="52">
10.
</td>
<td valign="top" width="128">
10. A change involving
 appreciable increase in design speeds VD, VB, VMO,
 VC, or VA.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Certification assumptions
 invalidated. Requires new AFM to address performance and flight
 characteristics.
</td>
</tr>
<tr>
<td valign="top" width="52">
11.
</td>
<td valign="top" width="128">
Installation of a short
 take-off and landing (STOL) kit.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Certification assumptions
 invalidated. Requires new AFM to address performance and flight
 characteristics.
</td>
</tr>
<tr>
<td valign="top" width="52">
12.
</td>
<td valign="top" width="128">
A change to the rated power or
 thrust could be a significant change if the applicant is taking credit for
 increased design speeds per example 10 of this table.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Certification assumptions
 invalidated. Requires new AFM to address performance and flight characteristics.
</td>
</tr>
<tr>
<td valign="top" width="52">
13.
</td>
<td valign="top" width="128">
Fuel state, such as compressed
 gaseous fuels or fuel cells. This could completely alter the fuel storage
 and handling systems and possibly affect the aeroplane structure.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Changes to design/certification
 assumptions. Extensive alteration of fuel storage and handling systems.
</td>
</tr>
<tr>
<td valign="top" width="52">
14.
</td>
<td valign="top" width="128">
A change to the flight control
 concept for an aircraft, e.g. to fly-by-wire (FBW) and side-stick control,
 or a change from hydraulic to electronically actuated flight controls, would
 in isolation normally be regarded as a significant change.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Changes to design and
 certification assumptions. Requires extensive systems architecture and
 integration reinvestigation. Requires new AFM.
</td>
</tr>
<tr>
<td valign="top" width="52">
15.
</td>
<td valign="top" width="128">
Change to aeroplane’s operating
 altitude, or cabin operating pressure greater than 10 per cent in maximum
 cabin pressure differential.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
This typically invalidates
 certification assumptions and the fundamental approach used in
 decompression, structural strength, and fatigue. May require extensive airframe
 changes affecting load paths, fatigue evaluation, aeroelastic
 characteristics, etc. Invalidates design assumptions.
</td>
</tr>
<tr>
<td valign="top" width="52">
16.
</td>
<td valign="top" width="128">
Addition of a cabin
 pressurisation system.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Extensive airframe changes
 affecting load paths, fatigue evaluation, aeroelastic characteristics, etc.
 Invalidates design assumptions.
</td>
</tr>
<tr>
<td valign="top" width="52">
17.
</td>
<td valign="top" width="128">
Changes to types and number of
 emergency exits or an increase in maximum certified passenger capacity.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Emergency egress certification
 specifications exceed those previously substantiated. Invalidates
 assumptions of certification.
</td>
</tr>
<tr>
<td valign="top" width="52">
18.
</td>
<td valign="top" width="128">
A change to the required number
 of flight crew that necessitates a complete flight deck rearrangement,
 and/or an increase in pilot workload.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Extensive changes to avionics
 and aircraft systems. Invalidates certification assumptions. Requires new
 AFM.
</td>
</tr>
<tr>
<td valign="top" width="52">
19.
</td>
<td valign="top" width="128">
Expansion of an aircraft’s
 operating envelope.*
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes*
*Some changes may be deemed
 ‘not significant’ depending on the extent of the expansion.
</td>
<td valign="top" width="156">
An expansion of operating
 capability is a significant change (e.g. an increase in maximum altitude
 limitation, approval for flight in icing conditions, or an increase in
 airspeed limitations).
</td>
</tr>
<tr>
<td valign="top" width="52">
20.
</td>
<td valign="top" width="128">
Replacement of an aviation
 gasoline engine with an engine of approximately the same horsepower
 utilising, e.g. diesel, hybrid, or electrical power.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
A major change to the
 aeroplane. The general configuration and principles of construction will
 usually remain valid; however, the assumptions for certification are
 invalidated.
</td>
</tr>
<tr>
<td valign="top" width="52">
21.
</td>
<td valign="top" width="128">
Comprehensive flight deck
 upgrade, such as conversion from entirely federated, independent
 electromechanical flight instruments to highly integrated and combined
 electronic display systems with extensive use of software and/or complex
 electronic hardware.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Affects avionics and electrical
 systems integration and architecture concepts and philosophies.
This drives a reassessment of
 the human–machine interface, flight-crew workload, and re-evaluation of the
 original design flight deck assumptions.
</td>
</tr>
<tr>
<td valign="top" width="52">
22.
</td>
<td valign="top" width="128">
Introduction of autoland.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Invalidates original design
 assumptions.
</td>
</tr>
<tr>
<td valign="top" width="52">
23.
</td>
<td valign="top" width="128">
Conversion from a safe life
 design to a damage-tolerance-based design.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Where the airframe-established
 safe life limits change to damage-tolerance principles, then use of an
 inspection program in lieu of the safe life design limit invalidates the
 original assumptions used during certification.
</td>
</tr>
<tr>
<td valign="top" width="52">
24.
</td>
<td valign="top" width="128">
Extensive structural airframe
 modification, such as a large opening in the fuselage.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Requires extensive changes to
 fuselage structure, affects aircraft systems, and requires a new AFM to
 address performance and flight characteristics.
</td>
</tr>
<tr>
<td valign="top" width="52">
25.
</td>
<td valign="top" width="128">
Fuselage stretch or shortening
 in the cabin or pressure vessel.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Cabin interior changes are related
 changes since occupant safety considerations are impacted by a cabin length
 change. Even if a new cabin interior is not included in the product-level
 change, the functional effect of the fuselage plug has implications on
 occupant safety (e.g. the dynamic environment in an emergency landing,
 emergency evacuation, etc.), and thus the cabin interior becomes an affected
 area.
</td>
</tr>
<tr>
<td valign="top" width="52">
26.
</td>
<td valign="top" width="128">
Conversion from normal category
 to commuter category aeroplane.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Requires compliance with all
 commuter regulatory standards. In many cases, this change could be
 considered a substantial change to the type design. Therefore, a proposed
 change of this nature would be subject to EASA determination under 21.A.19.
</td>
</tr>
<tr>
<td valign="top" width="52">
27.
</td>
<td valign="top" width="128">
Installation of a full
 authority digital engine control (FADEC) on an aeroplane that did not
 previously have a FADEC installed.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
—
</td>
</tr>
</table>

A.1.3  Table A-3 contains examples of changes that
are ‘not significant’ for small aeroplanes (CS-23).

<table border="1" cellpadding="0" cellspacing="0" width="605">
<thead>
<tr>
<td colspan="6" width="605">
Table A-3.
 Examples of Not Significant Changes for Small Aeroplanes (CS-23)
</td>
</tr>
<tr>
<td width="52">
Example
</td>
<td width="127">
Description of change
</td>
<td width="89">
Is there a change to the
 general configuration? 21.A.101(b)(1)(i)
</td>
<td width="88">
Is there a change to the
 principles of construction? 21.A.101(b)(1)(i)
</td>
<td width="93">
Have the assumptions used
 for certification been invalidated? 21.A.101(b)(1)(ii)
</td>
<td width="156">
Notes
</td>
</tr>
</thead>
<tr>
<td valign="top" width="52">
1.
</td>
<td valign="top" width="127">
Addition of wingtip
 modifications (not winglets).
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
A major change to the
 aeroplane. Likely, the original general configuration, principles of
 construction, and certification assumptions remain valid.
</td>
</tr>
<tr>
<td valign="top" width="52">
2.
</td>
<td valign="top" width="127">
Installation of skis or wheel skis.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Although a major change to the aeroplane, likely the
 original general configuration, principles of construction, and
 certification assumptions remain valid.
</td>
</tr>
<tr>
<td valign="top" width="52">
3.
</td>
<td valign="top" width="127">
Forward looking infrared (FLIR) or surveillance camera
 installation.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Additional flight or structural evaluation may be
 necessary, but the change does not alter basic aeroplane certification.
</td>
</tr>
<tr>
<td valign="top" width="52">
4.
</td>
<td valign="top" width="127">
Litter, berth, and cargo tie down device installation.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
5.
</td>
<td valign="top" width="127">
Not an aeroplane-level change.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
6.
</td>
<td valign="top" width="127">
Replacement of one propeller type with another
 (irrespective of increase in number of blades).
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Although a major change to the aeroplane, likely the
 original general configuration, principles of construction, and
 certification assumptions remain valid.
</td>
</tr>
<tr>
<td valign="top" width="52">
7.
</td>
<td valign="top" width="127">
Addition of a turbo-charger that does not change the
 power envelope, operating range, or limitations (e.g. a turbo-normalised
 engine, where the additional power is used to enhance high-altitude or
 hot-day performance).
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
8.
</td>
<td valign="top" width="127">
Substitution of one method of bonding for another (e.g.
 change to type of adhesive).
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
9.
</td>
<td valign="top" width="127">
Substitution of one type of metal for another.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
10.
</td>
<td valign="top" width="127">
Any change to construction or fastening not involving
 primary structure.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
11.
</td>
<td valign="top" width="127">
A new fabric type for fabric-skinned aircraft.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
12.
</td>
<td valign="top" width="127">
Increase in flap speed or undercarriage limit speed.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Although a major change to the aeroplane, likely the
 original general configuration, principles of construction, and
 certification assumptions remain valid.
</td>
</tr>
<tr>
<td valign="top" width="52">
13.
</td>
<td valign="top" width="127">
Structural strength increases.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Although a major change to the aeroplane, likely the
 original general configuration, principles of construction, and certification
 assumptions remain valid.
</td>
</tr>
<tr>
<td valign="top" width="52">
14.
</td>
<td valign="top" width="127">
Instrument flight rules (IFR) upgrades involving
 installation of components (where the original certification does not
 indicate that the aeroplane is not suitable as an IFR platform, e.g. special
 handling concerns).
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
15.
</td>
<td valign="top" width="127">
Fuel tanks where fuel is changed from gasoline to diesel
 fuel and tank support loads are small enough that an extrapolation from the
 previous analysis would be valid. Chemical compatibility would have to be
 substantiated.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
16.
</td>
<td valign="top" width="127">
Limited changes to a pressurisation system, e.g. number
 of outflow valves, type of controller, or size of pressurised compartment,
 but the system must be re-substantiated if the original test data are
 invalidated.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Although a major change to the aeroplane, likely the
 original general configuration, principles of construction, and
 certification assumptions remain valid.
</td>
</tr>
<tr>
<td valign="top" width="52">
17.
</td>
<td valign="top" width="127">
Install a different exhaust system.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
18.
</td>
<td valign="top" width="127">
Changes to engine cooling or cowling.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
19.
</td>
<td valign="top" width="127">
Changing fuels of substantially the same type, such as
 AvGas to AutoGas, AvGas (80/87) to AvGas (100LL), ethanol to isopropyl
 alcohol, Jet B to Jet A.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Although a major change to the aeroplane, likely the
 original general configuration, principles of construction, and
 certification assumptions remain valid.
</td>
</tr>
<tr>
<td valign="top" width="52">
20.
</td>
<td valign="top" width="127">
Fuels that specify different levels of ‘conventional’
 fuel additives that do not change the primary fuel type. Different additive
 levels (controlled) of MTBE, ETBE, ethanol, amines, etc., in AvGas would not
 be considered a significant change.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Although a major change to the aeroplane, likely the
 original general configuration, principles of construction, and
 certification assumptions remain valid.
</td>
</tr>
<tr>
<td valign="top" width="52">
21.
</td>
<td valign="top" width="127">
A change to the maximum take-off weight of less than 5
 per cent, unless assumptions made in justification of the design are thereby
 invalidated.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Although a major change to the aeroplane, likely the
 original general configuration, principles of construction, and
 certification assumptions remain valid.
</td>
</tr>
<tr>
<td valign="top" width="52">
22.
</td>
<td valign="top" width="127">
An additional aileron tab (e.g. on the other wing).
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Although a major change to the aeroplane, likely the
 original general configuration, principles of construction, and
 certification assumptions remain valid.
</td>
</tr>
<tr>
<td valign="top" width="52">
23.
</td>
<td valign="top" width="127">
Larger diameter flight control cables with no change to
 routing, or other system design.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
24.
</td>
<td valign="top" width="127">
Autopilot installation (for IFR use, unless the original
 certification indicates that the aeroplane is not suitable as an IFR
 platform).
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Although a major change to the aeroplane, likely the
 original general configuration, principles of construction, and
 certification assumptions remain valid.
</td>
</tr>
<tr>
<td valign="top" width="52">
25.
</td>
<td valign="top" width="127">
Increased battery capacity or relocate battery.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
26.
</td>
<td valign="top" width="127">
Replace generator with alternator.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
27.
</td>
<td valign="top" width="127">
Additional lighting (e.g. navigation lights, strobes).
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
28.
</td>
<td valign="top" width="127">
Higher capacity brake assemblies.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
29.
</td>
<td valign="top" width="127">
Increase in fuel tank capacity.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
30.
</td>
<td valign="top" width="127">
Addition of an oxygen system.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
31.
</td>
<td valign="top" width="127">
Relocation of a galley.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
32.
</td>
<td valign="top" width="127">
Passenger-to-freight (only) conversion with no change to
 basic fuselage structure.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Although a major change to the aeroplane, likely the
 original general configuration, principles of construction, and
 certification assumptions remain valid.
Requires certification substantiation applicable to
 freighter certification specifications.
</td>
</tr>
<tr>
<td valign="top" width="52">
33.
</td>
<td valign="top" width="127">
New cabin interior with no fuselage length change.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
34.
</td>
<td valign="top" width="127">
Installation of new seat belt or shoulder harness.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
35.
</td>
<td valign="top" width="127">
A small increase in centre of gravity (CG) range.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
At aeroplane level, no change to general configuration,
 principles of construction, and certification assumptions.
</td>
</tr>
<tr>
<td valign="top" width="52">
36.
</td>
<td valign="top" width="127">
Auxiliary power unit (APU) installation that is not
 flight-essential.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Although a major change to the aeroplane level, likely
 the original general configuration, principles of construction, and
 certification assumptions remain valid.
Requires certification substantiation applicable to APU
 installation certification specifications.
</td>
</tr>
<tr>
<td valign="top" width="52">
37.
</td>
<td valign="top" width="127">
An alternative autopilot.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
38.
</td>
<td valign="top" width="127">
Addition of Class B terrain awareness and warning system
 (TAWS).
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not an aeroplane-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
39.
</td>
<td valign="top" width="127">
Extending an established life limit.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
This extension may be accomplished by various methods,
 such as ongoing fatigue testing, service life evaluation, component level
 replacement, and inspections based on damage-tolerance principles.
</td>
</tr>
<tr>
<td valign="top" width="52">
40.
</td>
<td valign="top" width="127">
Flight deck replacement of highly integrated and combined
 electronic display systems with other highly integrated and combined
 electronic display systems.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not significant if the architecture concepts, design
 philosophies, human–machine interface, or flight-crew workload assumptions
 are not impacted.
</td>
</tr>
<tr>
<td valign="top" width="52">
41.
</td>
<td valign="top" width="127">
Interior cabin reconfigurations are generally considered
 not significant. This includes installation of in-flight entertainment
 (IFE), new seats, and rearrangement of furniture.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
42.
</td>
<td valign="top" width="127">
Modification to ice protection systems.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Recertification required, but certification basis should
 be evaluated for adequacy.
</td>
</tr>
</table>

A.2    Examples of Substantial, Significant, and
Not Significant Changes for Large Aeroplanes
(CS-25).

A.2.1     Table
A-4 contains examples of changes that are ‘substantial’ for large aeroplanes
(CS-25).

Table
A-4. Examples of Substantial Changes for Large Aeroplanes (CS-25)

<table border="1" cellpadding="0" cellspacing="0" width="605">
<tr>
<td valign="top" width="62">
Example
</td>
<td valign="top" width="251">
Description of Change
</td>
<td valign="top" width="292">
Notes
</td>
</tr>
<tr>
<td width="62">
1.
</td>
<td width="251">
Change to the number or location of engines, e.g. four to
 two wing-mounted engines or two wing-mounted to two body-mounted engines.
</td>
<td width="292">
Proposed change to design is so extensive that a
 substantially complete investigation of compliance with the applicable
 certification basis is required.
</td>
</tr>
<tr>
<td width="62">
2.
</td>
<td width="251">
Change from a high-wing to low-wing configuration.
</td>
<td width="292">
Proposed change to design is so extensive that a
 substantially complete investigation of compliance with the applicable
 certification basis is required.
</td>
</tr>
<tr>
<td width="62">
3.
</td>
<td width="251">
Change from an all-metal to all-composite aeroplane.
</td>
<td width="292">
Proposed change to design is so extensive that a
 substantially complete investigation of compliance with the applicable
 certification basis is required.
</td>
</tr>
<tr>
<td width="62">
4.
</td>
<td width="251">
Change of empennage configuration for larger aeroplanes
 (cruciform vs ‘T’ or ‘V’ tail).
</td>
<td width="292">
Proposed change to design is so extensive that a
 substantially complete investigation of compliance with the applicable
 certification basis is required.
</td>
</tr>
<tr>
<td width="62">
5.
</td>
<td width="251">
Increase from subsonic to supersonic flight regime.
</td>
<td width="292">
Proposed change to design is so extensive that a
 substantially complete investigation of compliance with the applicable
 certification basis is required.
</td>
</tr>
</table>

A.2.2     Table A-5 contains examples of changes
that are ‘significant’ for large aeroplanes (CS-25).

<table border="1" cellpadding="0" cellspacing="0" width="605">
<thead>
<tr>
<td colspan="6" width="605">
Table A-5.
 Examples of Significant Changes for Transport Large Aeroplanes (CS-25)
</td>
</tr>
<tr>
<td width="52">
Example
</td>
<td width="127">
Description of change
</td>
<td width="89">
Is there a change to the
 general configuration? 21.A.101(b)(1)(i)
</td>
<td width="88">
Is there a change to the
 principles of construction? 21.A.101(b)(1)(i)
</td>
<td width="93">
Have the assumptions used
 for certification been invalidated? 21.A.101(b)(1)(ii)
</td>
<td width="156">
Notes
</td>
</tr>
</thead>
<tr>
<td valign="top" width="52">
1.
</td>
<td valign="top" width="127">
Reduction in the number of
 flight crew (in conjunction with flight deck update).
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Extensive changes to avionics
 and aircraft systems. Impact to flight-crew workload and human factors,
 pilot type rating.
</td>
</tr>
<tr>
<td valign="top" width="52">
2.
</td>
<td valign="top" width="127">
Modify an aeroplane to add certification for flight in
 icing conditions by adding systems, such as ice detection and ice
 protection.
</td>
<td valign="top" width="89">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
New aircraft operating envelope. Requires major new
 systems installation and aircraft evaluation. Operating envelope changed.
</td>
</tr>
<tr>
<td valign="top" width="52">
3.
</td>
<td valign="top" width="127">
Conversion — passenger or combination freighter/passenger
 to all-freighter, including cargo door, redesign floor structure and 9g net
 or rigid barrier.
</td>
<td valign="top" width="89">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Extensive airframe changes affecting load paths,
 aeroelastic characteristics, aircraft-related systems for fire protection,
 etc. Design assumptions changed from passenger to freighter.
</td>
</tr>
<tr>
<td valign="top" width="52">
4.
</td>
<td valign="top" width="127">
Conversion from a cargo to passenger configuration.
</td>
<td valign="top" width="89">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Completely new floor loading and design. Redistribution
 of internal loads, change to cabin safety certification specifications,
 system changes.
</td>
</tr>
<tr>
<td valign="top" width="52">
5.
</td>
<td valign="top" width="127">
Increase in cabin pressurisation greater than 10 per
 cent.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
A change greater than 10 per cent in operational cabin
 pressure differential is a significant change since it requires extensive
 airframe changes affecting load paths, fatigue evaluation, or aeroelastic
 characteristics, invalidating the certification assumptions.
</td>
</tr>
<tr>
<td valign="top" width="52">
6.
</td>
<td valign="top" width="127">
Addition of leading-edge slats.
</td>
<td valign="top" width="89">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
The addition of leading-edge slats is significant since
 it requires extensive changes to wing structure, adds aircraft systems, and
 requires a new AFM to address performance and flight characteristics.
</td>
</tr>
<tr>
<td valign="top" width="52">
7.
</td>
<td valign="top" width="127">
Fuselage stretch or shortening in the cabin or pressure
 vessel.
</td>
<td valign="top" width="89">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Cabin interior changes are related changes since occupant
 safety considerations are impacted by a cabin length change. Even if a new
 cabin interior is not included in the product-level change, the functional
 effect of the fuselage plug has implications on occupant safety (e.g. the
 dynamic environment in an emergency landing, emergency evacuation, etc.),
 and thus the cabin interior becomes an affected area.
</td>
</tr>
<tr>
<td valign="top" width="52">
8.
</td>
<td valign="top" width="127">
Extensive structural airframe modification, such as
 installation of a large telescope with large opening in the fuselage.
</td>
<td valign="top" width="89">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
These types of structural modifications are significant
 since they require extensive changes to fuselage structure, affect aircraft
 systems, and require a new AFM to address performance and flight
 characteristics.
</td>
</tr>
<tr>
<td valign="top" width="52">
9.
</td>
<td valign="top" width="127">
Changing the number of axles or number of landing gear
 done in context with a product change that involves changing the aeroplane’s
 gross weight.
</td>
<td valign="top" width="89">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
This type of landing gear change with an increase in
 gross weight is significant since it requires changes to aircraft structure,
 affects aircraft systems, and requires AFM changes, which invalidate the
 certification assumptions.
</td>
</tr>
<tr>
<td valign="top" width="52">
10.
</td>
<td valign="top" width="127">
Primary structure changes from metallic material to
 composite material.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Change to principles of construction and design from
 conventional practices.
</td>
</tr>
<tr>
<td valign="top" width="52">
11.
</td>
<td valign="top" width="127">
An increase in design weight of more than 10 per cent.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Design weight increases of more than 10 per cent result
 in significant design load increase that invalidates the assumptions used
 for certification, requiring re-substantiation of aircraft structure,
 aircraft performance, and flying qualities and associated systems.
</td>
</tr>
<tr>
<td valign="top" width="52">
12.
</td>
<td valign="top" width="127">
Installation of winglets, modification of existing
 winglets, or other changes to wing tip design.
</td>
<td valign="top" width="89">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Significant if it requires extensive changes to wing
 structure or aircraft systems, or if it requires a new AFM to address
 performance and flight characteristics. It may also affect the wing fuel
 tanks, including fuel tank lightning protection, fuel tank ignition source
 prevention, and fuel tank flammability exposure.
</td>
</tr>
<tr>
<td valign="top" width="52">
13.
</td>
<td valign="top" width="127">
Changes to wing span, chord, or sweep.
</td>
<td valign="top" width="89">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Significant if it requires extensive changes to wing
 structure or aircraft systems, or if it requires a new AFM to address
 performance and flight characteristics. It may also affect the wing fuel
 tanks, including fuel tank lightning protection, fuel tank ignition source
 prevention, and fuel tank flammability exposure.
</td>
</tr>
<tr>
<td valign="top" width="52">
14.
</td>
<td valign="top" width="127">
A change to the type or number of emergency exits or an
 increase in the maximum certified number of passengers.
</td>
<td valign="top" width="89">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
15.
</td>
<td valign="top" width="127">
A comprehensive avionics upgrade that changes a federated
 avionics system to a highly integrated avionics system.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
This change refers to the avionics system that feeds the
 output to displays and not the displays themselves.
</td>
</tr>
<tr>
<td valign="top" width="52">
16.
</td>
<td valign="top" width="127">
An avionics upgrade that changes the method of input from
 the flight crew, which was not contemplated during the original
 certification.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
A change that includes touchscreen technology typically
 does not invalidate the assumptions used for certification. A change that
 incorporates voice-activated controls or other novel human–machine interface
 would likely invalidate the assumptions used for certification.
</td>
</tr>
<tr>
<td valign="top" width="52">
17.
</td>
<td valign="top" width="127">
Change to primary flight controls to FBW system. (Some
 aeroplanes have some degree of FBW. Achieving full FBW may be a not
 significant change on some aeroplanes.)
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
When the degree of change is so extensive that it affects
 basic aircraft systems integration and architecture concepts and
 philosophies. This drives a complete reassessment of flight-crew workload,
 handling qualities, and performance evaluation, which are different from the
 original design assumptions.
</td>
</tr>
<tr>
<td valign="top" width="52">
18.
</td>
<td valign="top" width="127">
Replace reciprocating with turbo-propeller engines.
</td>
<td valign="top" width="89">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Requires extensive changes to airframe structure,
 addition of aircraft systems, and new AFM to address performance and flight
 characteristics.
</td>
</tr>
<tr>
<td valign="top" width="52">
19.
</td>
<td valign="top" width="127">
Maximum continuous or take-off thrust or power increase
 of more than 10 per cent or, for turbofans, an increase of the nacelle
 diameter.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
A thrust or power increase of more than 10 per cent is
 significant because it does have a marked effect on aircraft performance and
 flying qualities, or requires re-substantiation of powerplant installation.
 An increase of the nacelle diameter as a result of an increase in the bypass
 ratio is significant because it results in airframe-level effects on
 aircraft performance and flying qualities. However, a small increase of the
 nacelle diameter would not have such an airframe-level effect and would not
 be considered a significant change.
</td>
</tr>
<tr>
<td valign="top" width="52">
20.
</td>
<td valign="top" width="127">
Initial installation of an autoland system.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Baseline aeroplane not designed for autoland operation,
 potential flight-crew workload, and systems compatibility issues.
</td>
</tr>
<tr>
<td valign="top" width="52">
21.
</td>
<td valign="top" width="127">
Installation of a new fuel tank, e.g. installation of an
 auxiliary fuel tank in a cargo bay or installation of an auxiliary fuel tank
 that converts a dry bay into a fuel tank (such as a horizontal stabiliser
 tank).
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Requires changes to airframe, systems, and AFM. Results
 in performance changes. These changes typically affect fuel tank lightning
 protection, fuel tank ignition source prevention, and fuel tank flammability
 exposure.
</td>
</tr>
<tr>
<td valign="top" width="52">
22.
</td>
<td valign="top" width="127">
Main deck cargo door installation.
</td>
<td valign="top" width="89">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Redistribution of internal loads, change to aeroelastic
 characteristics, system changes.
</td>
</tr>
<tr>
<td valign="top" width="52">
23.
</td>
<td valign="top" width="127">
Expansion of an aircraft’s operating envelope.*
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes*
*Some changes may be deemed ‘not significant’ depending
 on the extent of the expansion.
</td>
<td valign="top" width="156">
An expansion of operating capability is a significant
 change (e.g. an increase in maximum altitude limitation, approval for flight
 in icing conditions, or an increase in airspeed limitations).
</td>
</tr>
<tr>
<td valign="top" width="52">
24.
</td>
<td valign="top" width="127">
Changing the floor from passenger-carrying to
 cargo-carrying capability.
</td>
<td valign="top" width="89">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Completely new floor loading and design. Redistribution
 of internal loads, change to cabin safety certification specifications,
 system changes. If a cargo handling system is installed, it would be a
 related change.
</td>
</tr>
<tr>
<td valign="top" width="52">
25.
</td>
<td valign="top" width="127">
Initial installation of an APU essential for aircraft
 flight operation.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Changes to emergency electrical power certification
 specifications, change to aircraft flight manual and operating
 characteristics.
</td>
</tr>
<tr>
<td valign="top" width="52">
26.
</td>
<td valign="top" width="127">
Conversion from hydraulically actuated brakes to
 electrically actuated brakes.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Assumptions of certification for aeroplane performance
 are changed.
</td>
</tr>
<tr>
<td valign="top" width="52">
27.
</td>
<td valign="top" width="127">
Installation of engine thrust reversers.
</td>
<td valign="top" width="89">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
</td>
</tr>
<tr>
<td valign="top" width="52">
28.
</td>
<td valign="top" width="127">
Request for extended-range operations (ETOPS) type design
 approval for: (a) aeroplanes without an existing ETOPS type design approval,
 and 
 (b) extension of an aeroplane’s diversion time.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
An expansion of diversion capability for ETOPS would
 normally be a significant change. However, expanding the diversion
 capability for which it was originally designed is generally not a
 significant change. In this case, the assumptions used for certification of
 the basic product remain valid, and the results can be applied to cover the
 changed product with predictable effects or can be demonstrated without
 significant physical changes to the product.
</td>
</tr>
<tr>
<td valign="top" width="52">
29.
</td>
<td valign="top" width="127">
Installation of an engine with a FADEC on an aeroplane
 that did not previously have a FADEC engine installed.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
A change from a mechanical control engine to a FADEC
 engine may be so extensive that it affects basic aircraft systems
 integration and architecture concepts and philosophies. This drives a
 complete reassessment of flight-crew workload, handling qualities, and
 performance evaluation, which are different from the original design
 assumptions.
</td>
</tr>
</table>

A.2.3     Table
A-6 contains examples of changes that are ‘not significant’ for large
aeroplanes (CS-25).

<table border="1" cellpadding="0" cellspacing="0" width="605">
<thead>
<tr>
<td colspan="6" width="605">
Table A-6.
 Examples of Not Significant Changes for Large Aeroplanes (CS-25)
</td>
</tr>
<tr>
<td width="52">
Example
</td>
<td width="127">
Description of change
</td>
<td width="89">
Is there a change to the
 general configuration? 21.A.101(b)(1)(i)
</td>
<td width="88">
Is there a change to the
 principles of construction? 21.A.101(b)(1)(i)
</td>
<td width="93">
Have the assumptions used
 for certification been invalidated? 21.A.101(b)(1)(ii)
</td>
<td width="156">
Notes
</td>
</tr>
</thead>
<tr>
<td valign="top" width="52">
1.
</td>
<td valign="top" width="127">
Alternate engine installation
 or hush kit at same position.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
It is not significant so long
 as there is less than a 10 per cent increase in thrust or there is not a
 change to the principles of propulsion. A change to position to accommodate
 a different engine size could influence aeroplane performance and handling qualities
 and result in a significant change.
</td>
</tr>
<tr>
<td valign="top" width="52">
2.
</td>
<td valign="top" width="127">
A small change to fuselage length due to re-fairing the
 aft body or radome.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
For cruise performance reasons, where such changes do not
 require extensive structural, systems, aerodynamic, or AFM changes.
</td>
</tr>
<tr>
<td valign="top" width="52">
3.
</td>
<td valign="top" width="127">
Re-fairing of wing tip caps (for lights, fuel dump pipes)
 and addition of splitter plates to the trailing edge thickness of the cruise
 aerofoil.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Does not require extensive structural, AFM, or systems
 changes.
</td>
</tr>
<tr>
<td valign="top" width="52">
4.
</td>
<td valign="top" width="127">
Additional power used to enhance high-altitude or hot-day
 performance.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Usually no change to basic operating envelope. Existing
 certification data can be extrapolated. Could be significant product change
 if the additional power is provided by installation of a rocket motor or
 additional, on demand engine due to changes to certification assumptions.
</td>
</tr>
<tr>
<td valign="top" width="52">
5.
</td>
<td valign="top" width="127">
Installation of an autopilot system.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
N/A
</td>
<td valign="top" width="93">
See notes
</td>
<td valign="top" width="156">
It may be possible that the modification is adaptive in
 nature, with no change to original certification assumptions. However, in
 certain cases the installation of an autopilot may include extensive changes
 and design features that change both the general configuration and the
 assumptions for certification (i.e. installation of the autopilot may
 introduce a number of additional mechanical and electronic failure modes and
 change the hazard classification of given aircraft-level failures).
</td>
</tr>
<tr>
<td valign="top" width="52">
6.
</td>
<td valign="top" width="127">
Change from assembled primary structure to monolithic or
 integrally machined structure.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Method of construction must be well understood.
</td>
</tr>
<tr>
<td valign="top" width="52">
7.
</td>
<td valign="top" width="127">
Modification to ice protection systems.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Recertification required, but certification basis is
 adequate.
</td>
</tr>
<tr>
<td valign="top" width="52">
8.
</td>
<td valign="top" width="127">
Brakes: design or material change, e.g. steel to carbon.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Recertification required, but certification basis is adequate.
</td>
</tr>
<tr>
<td valign="top" width="52">
9.
</td>
<td valign="top" width="127">
Redesign floor structure.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
By itself, not a significant product change. It is
 significant if part of a cargo conversion of a passenger aeroplane.
</td>
</tr>
<tr>
<td valign="top" width="52">
10.
</td>
<td valign="top" width="127">
New cabin interior with no fuselage length change.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
A new cabin interior includes new ceiling and sidewall
 panels, stowage, galleys, lavatories, and seats. Novel or unusual design
 features in the cabin interior may require special conditions. Many
 interior-related certification specifications are incorporated in operational
 rules. Even though the design approval holder may not be required to comply
 with these certification specifications, the operator may be required to
 comply.
</td>
</tr>
<tr>
<td valign="top" width="52">
11.
</td>
<td valign="top" width="127">
A rearrangement of an interior (e.g. seats, galleys,
 lavatories, closets, etc.).
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
12.
</td>
<td valign="top" width="127">
Novel or unusual method of construction of a component.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
The component change does not rise to the product level.
 Special conditions could be required if there are no existing certification
 specifications that adequately address these features.
</td>
</tr>
<tr>
<td valign="top" width="52">
13.
</td>
<td valign="top" width="127">
Initial installation of a non-essential APU.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
A stand-alone initial APU installation on an aeroplane
 originally designed to use ground- or airport-supplied electricity and air
 conditioning. In this case, the APU would be an option to be independent of
 airport power.
</td>
</tr>
<tr>
<td valign="top" width="52">
14.
</td>
<td valign="top" width="127">
Increasing the life limit as CS 25.571 fatigue testing
 progresses for a recently type-certified aeroplane.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
For example, a recently type-certified aeroplane may
 undergo fatigue testing as part of compliance with CS 25.571. In this case,
 the TC holder may specify an initial life limit in the airworthiness
 limitations section (ALS) and gradually increase that life limit as fatigue
 testing progresses. Such change to the ALS is considered not significant.
</td>
</tr>
<tr>
<td valign="top" width="52">
15.
</td>
<td valign="top" width="127">
Extending limit of validity (LOV)
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Extending an LOV without any other change to the
 aeroplane is not a significant change. However, if extending the LOV
 requires a physical design change to the aeroplane, the design change is
 evaluated to determine the level of significance of the design change.
</td>
</tr>
<tr>
<td valign="top" width="52">
16.
</td>
<td valign="top" width="127">
Airframe life extension.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
This does not include changes that involve changes to
 design loads, such as pressurisation or weight increases. Also, this does
 not include changing from safe life to damage tolerance.
</td>
</tr>
<tr>
<td valign="top" width="52">
17.
</td>
<td valign="top" width="127">
Changes to the type or number of emergency exits by
 de-rating doors or deactivating doors with corresponding reduction in
 passenger capacity.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
The new emergency egress does not exceed that previously
 substantiated because the certified number of passengers is reduced.
</td>
</tr>
<tr>
<td valign="top" width="52">
18.
</td>
<td valign="top" width="127">
Request for ETOPS type design approval for a type design
 change of a product with an existing ETOPS type design approval.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
A change to a product with an existing ETOPS type design
 approval without a change to diversion capability would normally not be
 significant. However, if the existing ETOPS type design approval was based
 on policy prior to the adoption of transport category ETOPS airworthiness
 standards, then there is not an adequate certification basis to evaluate the
 type design change for ETOPS. 
 In this case, the change is still not significant, and the appropriate
 transport category ETOPS airworthiness standards would apply.
</td>
</tr>
<tr>
<td valign="top" width="52">
19.
</td>
<td valign="top" width="127">
An avionics change from federated electromechanical
 displays to federated electronic displays.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Changing an electromechanical display to an electronic
 display is not considered significant.
</td>
</tr>
<tr>
<td valign="top" width="52">
20.
</td>
<td valign="top" width="127">
An avionics change replacing an integrated avionics
 system with another integrated avionics system.
</td>
<td valign="top" width="89">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
The assumptions used to certify a highly integrated
 avionics system should be the same for another highly integrated avionics
 system.
</td>
</tr>
</table>

A.3    Examples of Substantial, Significant, and
Not Significant Changes for Rotorcraft (CS-27 and
CS-29).

A.3.1     Table
A-7 contains examples of changes that are ‘substantial’ for rotorcraft (CS-27
and CS-29).

Table
A-7. Examples of Substantial Changes for Rotorcraft (CS-27 and 29)

A.3.2     Table
A-8 contains examples of changes that are ‘significant’ for rotorcraft (CS-27
and CS-29).

<table border="1" cellpadding="0" cellspacing="0" width="605">
<thead>
<tr>
<td colspan="6" width="605">
Table A-8. Examples of
 Significant Changes for Rotorcraft (CS-27 and CS-29)
</td>
</tr>
<tr>
<td width="52">
Example
</td>
<td width="128">
Description of change
</td>
<td width="88">
Is there a change to the general configuration?
 21.A.101(b)(1)(i)
</td>
<td width="88">
Is there a change to the principles of
 construction? 21.A.101(b)(1)(i)
</td>
<td width="93">
Have the assumptions used for certification
 been invalidated? 21.A.101(b)(1)(ii)
</td>
<td width="156">
Notes
</td>
</tr>
</thead>
<tr>
<td valign="top" width="52">
1.
</td>
<td valign="top" width="128">
Comprehensive flight deck
 upgrade, such as conversion from entirely federated, independent
 electromechanical flight instruments to highly integrated and combined
 electronic display systems with extensive use of software and/or complex
 electronic hardware.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Affects avionics and electrical
 systems integration and architecture concepts and philosophies.
This drives a reassessment of
 the human–machine interface, flight-crew workload, and re-evaluation of the
 original design flight deck assumptions.
</td>
</tr>
<tr>
<td valign="top" width="52">
2.
</td>
<td valign="top" width="128">
Certification for flight into known icing conditions.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
</td>
</tr>
<tr>
<td valign="top" width="52">
3.
</td>
<td valign="top" width="128">
(Fixed) flying controls from
 mechanical to fly-by-wire.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
This drives a complete
 reassessment of the rotorcraft controllability and flight control failure.
</td>
</tr>
<tr>
<td valign="top" width="52">
4.
</td>
<td valign="top" width="128">
Addition of an engine; e.g.
 from single to twin or reduction of the number of engines; e.g. from twin to
 single.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
5.
</td>
<td valign="top" width="128">
A change of the rotor drive
 primary gearbox from a splash-type lubrication system to a
 pressure-lubricated system due to an increase in horsepower of an engine or
 changing from a piston engine to turbine engine.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
6.
</td>
<td valign="top" width="128">
A fuselage or tail boom
 modification that changes the primary structure, aerodynamics, and operating
 envelope sufficiently to invalidate the certification assumptions.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
7.
</td>
<td valign="top" width="128">
Application of an approved
 primary structure to a different approved model (e.g. installation on a
 former model of a main rotor that has been approved on a new model, and that
 results in increased performance).
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
8.
</td>
<td valign="top" width="128">
Emergency medical service (EMS)
 configuration with primary structural changes sufficient to invalidate the
 certification assumptions.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Many EMS configurations will
 not be classified as significant. Modifications made for EMS are typically
 internal, and the general external configuration is normally not affected.
 These changes should not automatically be classified as significant.
Note: Door addition or
 enlargement involving structural change would be significant.
</td>
</tr>
<tr>
<td valign="top" width="52">
9.
</td>
<td valign="top" width="128">
Skid landing gear to wheel
 landing gear or wheel landing to skid.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
10.
</td>
<td valign="top" width="128">
Change of the number of rotor
 blades.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
11.
</td>
<td valign="top" width="128">
Change of tail anti-torque
 device (e.g. tail rotor, ducted fan, or other technology).
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
12.
</td>
<td valign="top" width="128">
Passenger-configured helicopter
 to a firefighting-equipment-configured helicopter.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Depends on the firefighting
 configuration.
</td>
</tr>
<tr>
<td valign="top" width="52">
13.
</td>
<td valign="top" width="128">
Passenger-configured helicopter
 to an agricultural-configured helicopter.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Depends on the agricultural
 configuration.
</td>
</tr>
<tr>
<td valign="top" width="52">
14.
</td>
<td valign="top" width="128">
An initial Category A
 certification approval to an existing configuration.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
15.
</td>
<td valign="top" width="128">
IFR upgrades involving
 installation of upgraded components for new IFR configuration.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Changes to architecture
 concepts, design philosophies, human-machine interface, or flight-crew
 workload.
</td>
</tr>
<tr>
<td valign="top" width="52">
16.
</td>
<td valign="top" width="128">
Human external cargo (HEC)
 certification approval.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Must comply with the latest HEC
 certification specifications in order to obtain operational approval.
 Assumptions used for certification are considered invalidated when this
 leads to a significant re-evaluation, for example, of fatigue, quick-release
 systems, HIRF, one-engine-inoperative (OEI) performance, and OEI procedures.
</td>
</tr>
<tr>
<td valign="top" width="52">
17.
</td>
<td valign="top" width="128">
Reducing the number of pilots
 for IFR from two to one.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
18.
</td>
<td valign="top" width="128">
An avionics upgrade that
 changes a federated avionics system to a highly integrated avionics system.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
This change refers to the
 avionics system that feeds the output to displays and not the displays
 themselves.
</td>
</tr>
<tr>
<td valign="top" width="52">
19.
</td>
<td valign="top" width="128">
An avionics upgrade that
 changes the method of input from the flight crew, which was not contemplated
 during the original certification.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
A change that includes
 touchscreen technology typically does not invalidate the assumptions used
 for certification.
A change that incorporates
 voice-activated controls or other novel human-machine interface would likely
 invalidate the assumptions used for certification.
</td>
</tr>
</table>

A.3.3  Table A-9 contains examples of changes that
are ‘not significant’ changes for rotorcraft (CS-27 and CS-29).

<table border="1" cellpadding="0" cellspacing="0" width="605">
<thead>
<tr>
<td colspan="6" width="605">
Table A-9. Examples of Not
 Significant Changes for Rotorcraft (CS-27 and CS-29)
</td>
</tr>
<tr>
<td width="52">
Example
</td>
<td width="128">
Description of change
</td>
<td width="88">
Is there a change to the general configuration?
 21.A.101(b)(1)(i)
</td>
<td width="88">
Is there a change to the principles of construction?
 21.A.101(b)(1)(i)
</td>
<td width="93">
Have the assumptions used for certification
 been invalidated? 21.A.101(b)(1)(ii)
</td>
<td width="156">
Notes
</td>
</tr>
</thead>
<tr>
<td valign="top" width="52">
1.
</td>
<td valign="top" width="128">
Emergency floats.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Must comply with the specific
 applicable certification specifications for emergency floats. This installation,
 in itself, does not change the rotorcraft configuration, overall
 performance, or operational capability. Expanding an operating envelope
 (such as operating altitude and temperature) and mission profile (such as
 passenger-carrying operations to external-load operations, flight over
 water, or operations in snow conditions) are not by themselves so different
 that the original certification assumptions are no longer valid at the
 type-certified-product level.
</td>
</tr>
<tr>
<td valign="top" width="52">
2.
</td>
<td valign="top" width="128">
Forward looking infrared (FLIR) or surveillance camera installation.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Additional flight or structural evaluation may be
 necessary but the change does not alter the basic rotorcraft certification.
</td>
</tr>
<tr>
<td valign="top" width="52">
3.
</td>
<td valign="top" width="128">
Helicopter terrain awareness
 warning system (HTAWS) for operational credit.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Certified under rotorcraft
 HTAWS AMC guidance material and ETSO-C194. Does not alter the basic
 rotorcraft configuration.
</td>
</tr>
<tr>
<td valign="top" width="52">
4.
</td>
<td valign="top" width="128">
Health usage monitoring system
 (HUMS) for maintenance credit.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Certified under rotorcraft HUMS
 GM guidance material. Does not alter the basic rotorcraft configuration.
</td>
</tr>
<tr>
<td valign="top" width="52">
5.
</td>
<td valign="top" width="128">
Expanded limitations with
 minimal or no design changes, following further tests/justifications or
 different mix of limitations (CG limits, oil temperatures, altitude,
 minimum/maximum weight, minimum/ maximum external temperatures, speed,
 engine ratings).
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Changes to an operating
 envelope (such as operating altitude and temperature) and mission profile
 (such as passenger-carrying operations to external-load operations, flight
 over water, or operations in snow conditions) that are not so different that
 the original certification assumptions remain valid.
</td>
</tr>
<tr>
<td valign="top" width="52">
6.
</td>
<td valign="top" width="128">
Change from a single-channel
 FADEC to a dual-channel FADEC.
</td>
<td valign="top" width="88">
</td>
<td valign="top" width="88">
</td>
<td valign="top" width="93">
</td>
<td valign="top" width="156">
Change does not change the
 overall product configuration or the original certification assumptions.
</td>
</tr>
<tr>
<td valign="top" width="52">
7.
</td>
<td valign="top" width="128">
Installation of a new engine
 type, equivalent to the former one, leaving aircraft installation and
 limitations substantially unchanged.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Refer to AMC 27 or AMC 29 for
 guidance. Does not alter the basic rotorcraft configuration, provided there
 is no additional capacity embedded in the new design.
</td>
</tr>
<tr>
<td valign="top" width="52">
8.
</td>
<td valign="top" width="128">
Windscreen installation.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Does not change the rotorcraft
 overall product configuration.
</td>
</tr>
<tr>
<td valign="top" width="52">
9.
</td>
<td valign="top" width="128">
Snow skis, ‘Bear Paws.’
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Must comply with specific
 certification specifications associated with the change. Expanding an
 operating envelope (such as operating altitude and temperature) and mission
 profile (such as passenger-carrying operations to external-load operations,
 flight over water, or operations in snow conditions) are not by themselves
 so different that the original certification assumptions are no longer valid
 at the type-certified-product level.
</td>
</tr>
<tr>
<td valign="top" width="52">
10.
</td>
<td valign="top" width="128">
External cargo hoist.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Must comply with the specific
 applicable certification specifications for external loads. This
 installation, in itself, does not change the rotorcraft configuration,
 overall performance, or operational capability. Expanding an operating
 envelope (such as operating altitude and temperature) and mission profile
 (such as passenger-carrying operations to external-load operations
 (excluding HEC), flight over water, or operations in snow conditions) are
 not by themselves so different that the original certification assumptions
 are no longer valid at the type-certified-product level.
</td>
</tr>
<tr>
<td valign="top" width="52">
11.
</td>
<td valign="top" width="128">
IFR upgrades involving
 installation of upgraded components to replace existing components.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not a rotorcraft-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
12.
</td>
<td valign="top" width="128">
An avionics change from
 federated electromechanical displays to federated electronic displays.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Changing an electromechanical
 display to an electronic display on a single avionics display is not
 considered significant.
</td>
</tr>
<tr>
<td valign="top" width="52">
13.
</td>
<td valign="top" width="128">
An avionics change replacing an
 integrated avionics system with another integrated avionics system.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
The assumptions used to certify
 a highly integrated avionics system should be the same for another highly
 integrated avionics system.
</td>
</tr>
<tr>
<td valign="top" width="52">
14.
</td>
<td valign="top" width="128">
Flight deck replacement of
 highly integrated and combined electronic display systems with other highly
 integrated and combined electronic display systems.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Not significant if the
 architecture concepts, design philosophies, human–machine interface,
 flight-crew workload design and flight-deck assumptions are not impacted.
</td>
</tr>
<tr>
<td valign="top" width="52">
15.
</td>
<td valign="top" width="128">
IFR upgrades involving
 installation of upgraded components for new IFR configuration.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
No changes to architecture
 concepts, design philosophies, human–machine interface, or flight-crew
 workload.
</td>
</tr>
<tr>
<td valign="top" width="52">
16.
</td>
<td valign="top" width="128">
Flight deck replacement or
 upgrade of avionics systems in non-Appendix ‘B’ (IFR) or non-CAT ‘A’
 rotorcraft that can enhance safety or pilot awareness.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
17.
</td>
<td valign="top" width="128">
Modifications to
 non-crashworthy fuel systems intended to improve its crashworthiness.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
18.
</td>
<td valign="top" width="128">
Changing the hydraulic system
 from one similar type of fluid to another, e.g. a fluid change from a highly
 flammable mineral oil-based fluid 
 (MIL-H-5606) to a less flammable synthetic hydrocarbon-based fluid
 (MIL-PRF-87257)
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
19.
</td>
<td valign="top" width="128">
An ETSO C-127 dynamic seat
 installed in a helicopter with an existing certification basis prior to
 addition of CS 29.562, Emergency landing dynamic conditions.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
</td>
</tr>
</table>

A.4    Examples of Substantial, Significant, and Not Significant
Changes for Engines (CS-E)

A.4.1     Table
A-10 contains examples of changes that are ‘substantial’ for engines (CS-E).

Table
A-10. Examples of Substantial Changes for Engines (CS-E)

<table border="1" cellpadding="0" cellspacing="0" width="605">
<thead>
<tr>
<td valign="top" width="62">
Example
</td>
<td valign="top" width="251">
Description of Change
</td>
<td valign="top" width="292">
Notes
</td>
</tr>
</thead>
<tr>
<td colspan="3" width="605">
Turbine
 Engines
</td>
</tr>
<tr>
<td width="62">
1.
</td>
<td width="251">
Traditional turbofan to geared-fan engine.
</td>
<td width="292">
Proposed change to design is so extensive that a
 substantially complete investigation of compliance with the applicable
 certification basis is required.
</td>
</tr>
<tr>
<td width="62">
2.
</td>
<td width="251">
Low-bypass ratio engine to high-bypass ratio engine with
 an increased inlet area.
</td>
<td width="292">
Proposed change to design is so extensive that a
 substantially complete investigation of compliance with the applicable
 certification basis is required.
</td>
</tr>
<tr>
<td width="62">
3.
</td>
<td width="251">
Turbojet to turbofan.
</td>
<td width="292">
Proposed change to design is so extensive that a
 substantially complete investigation of compliance with the applicable
 certification basis is required.
</td>
</tr>
<tr>
<td width="62">
4.
</td>
<td width="251">
Turboshaft to turbo-propeller.
</td>
<td width="292">
Proposed change to design is so extensive that a
 substantially complete investigation of compliance with the applicable
 certification basis is required.
</td>
</tr>
<tr>
<td width="62">
5.
</td>
<td width="251">
Conventional ducted fan to unducted fan.
</td>
<td width="292">
Proposed change to design is so extensive that a
 substantially complete investigation of compliance with the applicable
 certification basis is required.
</td>
</tr>
<tr>
<td width="62">
6.
</td>
<td width="251">
Turbine engine for subsonic operation to afterburning
 engine for supersonic operation.
</td>
<td width="292">
Proposed change to design is so extensive that a
 substantially complete investigation of compliance with the applicable
 certification basis is required.
</td>
</tr>
</table>

A.4.2     Table
A-11 contains examples of changes that are ‘significant’ for engines (CS-E).

<table border="1" cellpadding="0" cellspacing="0" width="605">
<thead>
<tr>
<td colspan="6" width="605">
Table A-11. Examples of
 Significant Changes for Engines (CS-E)
</td>
</tr>
<tr>
<td width="52">
Example
</td>
<td width="128">
Description of change
</td>
<td width="88">
Is there a change to the general configuration?
 21.A.101(b)(1)(i)
</td>
<td width="88">
Is there a change to the principles of
 construction? 21.A.101(b)(1)(i)
</td>
<td width="93">
Have the assumptions used for certification
 been invalidated? 21.A.101(b)(1)(ii)
</td>
<td width="156">
Notes
</td>
</tr>
</thead>
<tr>
<td colspan="6" width="605">
Turbine
 Engines
</td>
</tr>
<tr>
<td valign="top" width="52">
1.
</td>
<td valign="top" width="128">
Increase/decrease in the number
 of compressor/turbine stages with resultant change to approved operational
 limitations.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Change is associated with other
 changes that would affect the rating of the engine and the engine dynamic
 behaviour, such as backbone bending, torque spike effects on rotors and
 casing, surge and stall characteristics, etc.
</td>
</tr>
<tr>
<td valign="top" width="52">
2.
</td>
<td valign="top" width="128">
New design fan blade and fan hub, or a bladed fan disk to
 a blisk, or a fan diameter change, that could not be retrofitted.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Change is associated with other changes to the engine
 thrust/power, ratings, and operating limitations; engine dynamic behaviour
 in terms of backbone bending, torque spike effects on casing, foreign object
 ingestion behaviour (birds, hail, rain, ice slab); blade-out test and
 containment; induction system icing capabilities; and burst model protection
 for the aircraft. If there is a diameter change, installation will be also
 affected.
</td>
</tr>
<tr>
<td valign="top" width="52">
3.
</td>
<td valign="top" width="128">
Hydromechanical control to
 FADEC/electronic engine control (EEC) without hydromechanical backup.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Change to engine control
 configuration. Not interchangeable. Likely fundamental change to engine
 operation.
</td>
</tr>
<tr>
<td valign="top" width="52">
4.
</td>
<td valign="top" width="128">
A change to the containment
 case from hard-wall to composite construction or vice versa that could not
 be retrofitted without additional major changes to the engine or restricting
 the initial limitations or restrictions in the initial installation manual.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Change to methods of
 construction that have affected inherent strength, backbone bending,
 blade-to-case clearance retention, containment wave effect on installation,
 effect on burst model, torque spike effects.
</td>
</tr>
<tr>
<td valign="top" width="52">
5.
</td>
<td valign="top" width="128">
A change to the gas generator
 (core, turbine/compressor/ combustor) in conjunction with changes to
 approved operating limitations.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Change is associated with other
 changes that would affect engine thrust/power and operating limitations, and
 have affected the dynamic behaviour of the engine, foreign object ingestion
 behaviour (birds, hail storm, rain, ice shed), induction system icing
 capabilities. Assumptions used for certification may no longer be valid.
</td>
</tr>
<tr>
<td valign="top" width="52">
6.
</td>
<td valign="top" width="128">
A change from traditional metal
 to composite materials on an assembly or structure that provides a load path
 for the engine affecting the engine dynamic behaviour and/or the engine
 inherent strength.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Change to principles of
 construction and design.
</td>
</tr>
<tr>
<td colspan="6" valign="top" width="605">
Piston
 Engines
</td>
</tr>
<tr>
<td valign="top" width="52">
7.
</td>
<td valign="top" width="128">
Convert from mechanical to
 electronic control system.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Change to engine configuration:
 installation interface of engine changed.
Changes to principles of
 construction: digital controllers and sensors require new construction
 techniques and environmental testing.
</td>
</tr>
<tr>
<td valign="top" width="52">
8.
</td>
<td valign="top" width="128">
Add turbocharger that increases
 performance and changes to overall product.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Change to general
 configuration: installation interface of engine changed (exhaust system).
Certification assumptions
 invalidated: change to operating envelope and performance.
</td>
</tr>
<tr>
<td valign="top" width="52">
9.
</td>
<td valign="top" width="128">
Convert from air-cooled
 cylinders to liquid-cooled cylinders.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Change to general
 configuration: installation interface of engine changed (cooling lines from
 radiator, change to cooling baffles). Certification assumptions invalidated:
 change to operating envelope and engine temperature certification
 specifications.
</td>
</tr>
<tr>
<td valign="top" width="52">
10.
</td>
<td valign="top" width="128">
A change from traditional metal
 to composite materials on an assembly or structure that provides a load path
 for the engine affecting the engine dynamic behaviour and/or the engine
 inherent strength.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Change to principles of
 construction and design.
</td>
</tr>
<tr>
<td valign="top" width="52">
11.
</td>
<td valign="top" width="128">
Convert from spark-ignition to
 compression-ignition.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Change to general
 configuration: installation interface of engine changed (no mixture lever).
Certification assumptions
 invalidated: change to operating envelope and performance.
</td>
</tr>
</table>

A.4.3     Table
A-12 contains examples of changes that are ‘not significant’ for engines
(CS-E).

<table border="1" cellpadding="0" cellspacing="0" width="605">
<thead>
<tr>
<td colspan="6" width="605">
Table A-12. Examples of Not
 Significant Changes for Engines (CS-E)
</td>
</tr>
<tr>
<td width="52">
Example
</td>
<td width="128">
Description of change
</td>
<td width="88">
Is there a change to the general configuration?
 21.A.101(b)(1)(i)
</td>
<td width="88">
Is there a change to the principles of
 construction? 21.A.101(b)(1)(i)
</td>
<td width="93">
Have the assumptions used for certification
 been invalidated? 21.A.101(b)(1)(ii)
</td>
<td width="156">
Notes
</td>
</tr>
</thead>
<tr>
<td colspan="6" width="605">
Turbine
 Engines
</td>
</tr>
<tr>
<td valign="top" width="52">
1.
</td>
<td valign="top" width="128">
Change to the material from one
 type of metal to another type of metal of a compressor drum.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
No change to performance.
 Assumptions are still valid.
</td>
</tr>
<tr>
<td valign="top" width="52">
2.
</td>
<td valign="top" width="128">
Increase/decrease in the number of compressor/turbine
 stages without resultant change to operational performance envelope.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
No change to performance. Assumptions are still valid.
</td>
</tr>
<tr>
<td valign="top" width="52">
3.
</td>
<td valign="top" width="128">
Hardware design changes to the FADEC/EEC, the
 introduction of which does not change the function of the system.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
No change to configuration. Retrofitable. 
 Assumptions used for certification are still valid. Possible changes to
 principles of construction are insignificant.
</td>
</tr>
<tr>
<td valign="top" width="52">
4.
</td>
<td valign="top" width="128">
Software changes.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
5.
</td>
<td valign="top" width="128">
Rub-strip design changes.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Component-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
6.
</td>
<td valign="top" width="128">
A new combustor that does not change the approved limitations
 or dynamic behaviour.*
(*Exclude life limits.)
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Component-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
7.
</td>
<td valign="top" width="128">
Bearing changes.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Component-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
8.
</td>
<td valign="top" width="128">
New blade designs with similar material that can be
 retrofitted.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Component-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
9.
</td>
<td valign="top" width="128">
Fan blade redesign that can be retrofitted.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Component-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
10.
</td>
<td valign="top" width="128">
Oil tank redesign.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Component-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
11.
</td>
<td valign="top" width="128">
Change from one hydromechanical control to another
 hydromechanical control.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Component-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
12.
</td>
<td valign="top" width="128">
Change to limits on life-limited components supported by
 data that became available after certification.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Extending or reducing the life limits. For example,
 extending life limits based on credits from service experience or new
 fatigue data.
</td>
</tr>
<tr>
<td valign="top" width="52">
13.
</td>
<td valign="top" width="128">
Changes to limits on exhaust gas temperature.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
</td>
</tr>
<tr>
<td valign="top" width="52">
14.
</td>
<td valign="top" width="128">
Changes to the Airworthiness Limitations section with no
 configuration changes.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
15.
</td>
<td valign="top" width="128">
Bump ratings within the product’s physical capabilities
 that may be enhanced with gas path changes, such as blade re-staggering,
 cooling hole patterns, blade coating changes, etc.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td colspan="6" width="605">
Piston
 Engines
</td>
</tr>
<tr>
<td valign="top" width="52">
16.
</td>
<td valign="top" width="128">
New or redesigned cylinder head, valves, or pistons.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
17.
</td>
<td valign="top" width="128">
Changes to crankshaft.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Component-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
18.
</td>
<td valign="top" width="128">
Changes to crankcase.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Component-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
19.
</td>
<td valign="top" width="128">
Changes to carburettor.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Component-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
20.
</td>
<td valign="top" width="128">
Changes to mechanical fuel injection system.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
</td>
</tr>
<tr>
<td valign="top" width="52">
21.
</td>
<td valign="top" width="128">
Changes to mechanical fuel injection pump.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Component-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
22.
</td>
<td valign="top" width="128">
Engine model change to accommodate new aircraft
 installation. No change to principles of operation of major subsystems; no
 significant expansion in power or operating envelopes or in limitations.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
23.
</td>
<td valign="top" width="128">
A simple mechanical change, or a change that does not
 affect the basic principles of operation. For example, change from dual
 magneto to two single magnetos on a model.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
24.
</td>
<td valign="top" width="128">
Subsystem change produces no changes to base engine input
 parameters, and previous analysis can be reliably extended. For example, a
 change to turbocharger where induction system inlet conditions remain
 unchanged, or if changed, the effects can be reliably extrapolated.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
—
</td>
</tr>
<tr>
<td valign="top" width="52">
25.
</td>
<td valign="top" width="128">
Change to material of secondary structure or not highly
 loaded component. For example, a change from metal to composite material in
 a non-highly loaded component, such as an oil pan that is not used as a
 mount pad.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Component-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
26.
</td>
<td valign="top" width="128">
Change to material that retains the physical properties
 and mechanics of load transfer. For example, a change to trace elements in a
 metal casting for ease of pouring or to update to a newer or more readily
 available alloy with similar mechanical properties.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Component-level change.
</td>
</tr>
</table>

A.5    Examples of
Substantial, Significant, and Not Significant Changes for Propellers (CS-P).

A.5.1     Table
A-13 contains an example of a change that is ‘substantial’ for propellers
(CS-P).

Table
A-13. Example of a Substantial Change for Propellers (CS-P)

A.5.2     Table
A-14 contains examples of changes that are ‘significant’ for propellers
(CS-P).

<table border="1" cellpadding="0" cellspacing="0" width="605">
<thead>
<tr>
<td colspan="6" width="605">
Table A-14. Examples of
 Significant Changes for Propellers (CS-P)
</td>
</tr>
<tr>
<td width="52">
Example
</td>
<td width="128">
Description of change
</td>
<td width="88">
Is there a change to the general configuration?
 21.A.101(b)(1)(i)
</td>
<td width="88">
Is there a change to the principles of
 construction? 21.A.101(b)(1)(i)
</td>
<td width="93">
Have the assumptions used for certification
 been invalidated? 21.A.101(b)(1)(ii)
</td>
<td width="156">
Notes
</td>
</tr>
</thead>
<tr>
<td valign="top" width="52">
1.
</td>
<td valign="top" width="128">
Principle of pitch change, such
 as a change from single acting to dual acting.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Requires extensive modification
 of the pitch change system with the introduction of backup systems. The
 inherent control system requires re-evaluation.
</td>
</tr>
<tr>
<td valign="top" width="52">
2.
</td>
<td valign="top" width="128">
Introduction of a different principle of blade retention,
 such as a single row to a dual row bearing.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Requires extensive modification of the propeller hub and
 blade structure. 
 The inherent strength requires re-evaluation.
</td>
</tr>
<tr>
<td valign="top" width="52">
3.
</td>
<td valign="top" width="128">
A hub configuration change, such as a split hub to a
 one-piece hub.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Requires extensive modification of the propeller hub
 structure. The inherent strength requires re-evaluation.
</td>
</tr>
<tr>
<td valign="top" width="52">
4.
</td>
<td valign="top" width="128">
Changing the method of mounting the propeller to the
 engine, such as a spline to a flange mount.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Requires extensive modification of the propeller hub
 structure. The inherent strength requires re-evaluation.
</td>
</tr>
<tr>
<td valign="top" width="52">
5.
</td>
<td valign="top" width="128">
Change to hub material from steel to aluminium.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Requires extensive modification of the propeller hub
 structure and change to method of blade retention. 
 The inherent strength requires re-evaluation.
</td>
</tr>
<tr>
<td valign="top" width="52">
6.
</td>
<td valign="top" width="128">
Change to blade material from metal to composite.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Requires extensive modification of the propeller blade
 structure and change to method of blade retention. Composite construction
 methods required. The inherent strength requires re-evaluation.
</td>
</tr>
<tr>
<td valign="top" width="52">
7.
</td>
<td valign="top" width="128">
Change from hydromechanical to electronic control.
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="88">
Yes
</td>
<td valign="top" width="93">
Yes
</td>
<td valign="top" width="156">
Electronic manufacturing and design methods required.
 Assumptions used for certification are no longer valid or not addressed in
 the original certification, i.e. HIRF and lightning protection, fault
 tolerance, software certification, and other aspects.
</td>
</tr>
</table>

A.5.3     Table A-15 contains examples of changes
that are ‘not significant’ for propellers (CS-P).

<table border="1" cellpadding="0" cellspacing="0" width="605">
<thead>
<tr>
<td colspan="6" width="605">
Table A-15. Examples of Not
 Significant Changes for Propellers (CS-P)
</td>
</tr>
<tr>
<td width="52">
Example
</td>
<td width="128">
Description of change
</td>
<td width="88">
Is there a change to the general configuration?
 21.A.101(b)(1)(i)
</td>
<td width="88">
Is there a change to the principles of
 construction? 21.A.101(b)(1)(i)
</td>
<td width="93">
Have the assumptions used for certification
 been invalidated? 21.A.101(b)(1)(ii)
</td>
<td width="156">
Notes
</td>
</tr>
</thead>
<tr>
<td valign="top" width="52">
1.
</td>
<td valign="top" width="128">
Change to the material of a
 blade bearing.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Component-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
2.
</td>
<td valign="top" width="128">
Change to a component in the
 control system.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Component-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
3.
</td>
<td valign="top" width="128">
Change to a propeller 
 de-icer boot.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Component-level change.
</td>
</tr>
<tr>
<td valign="top" width="52">
4.
</td>
<td valign="top" width="128">
Changes to the operational
 design envelope, such as increase in power.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Propeller’s operating
 characteristics and inherent strength require re-evaluation.
</td>
</tr>
<tr>
<td valign="top" width="52">
5.
</td>
<td valign="top" width="128">
Change to the intended usage,
 such as normal to acrobatic category.
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="88">
No
</td>
<td valign="top" width="93">
No
</td>
<td valign="top" width="156">
Propeller’s operating
 characteristics and inherent strength require re-evaluation.
</td>
</tr>
</table>