AMC1
ML.A.302(c) Aircraft maintenance programme
ED
Decision 2020/002/R
When
evaluating an alternative to a maintenance task issued or recommended by the
DAH, such as the extension of TBO intervals, or when considering not to
include a maintenance task issued or recommended by the DAH, a risk-based
approach should be taken, considering aspects such as the operation of
aircraft, type of aircraft, hours and years in service, maintenance of the
aircraft, compensating measures, redundancy of components, etc.
The
following table provides more details of aspects that should be considered:
|
|
Examples |
|
OPS approval |
HIGHER RISK: commercial operation, commercial
flight training MEDIUM RISK: flight training by an association,
non-commercial specialised operations (SPO) LOWER RISK: private |
|
Flight rules |
HIGHER RISK: instrument flight rules (IFR) MEDIUM RISK: visual flight rules (VFR) at night LOWER RISK: VFR by day |
|
Aircraft weight |
HIGHER RISK: Other than ELA1 MEDIUM RISK: ELA1 aircraft other than light sport
aeroplanes (LSA), very light aircraft (VLA), sailplanes and powered
sailplanes LOWER RISK: LSA, VLA, sailplanes and powered
sailplanes |
|
Who manages the airworthiness of the aircraft? |
HIGHER RISK: owner LOWER RISK: CAMO/CAO |
|
Who maintains the aircraft? |
HIGHER RISK: pilot-owner MEDIUM RISK: independent certifying staff LOWER RISK: maintenance organisation |
|
Time in service (flight hours, years) |
HIGHER RISK: very high number of hours or years MEDIUM RISK: medium number of hours or years LOWER RISK: low number of hours or years |
|
Aircraft utilisation |
HIGHER RISK: less than 50 h per year MEDIUM RISK: around 200 h per year LOWER RISK: more than 400 h per year |
|
ACAM findings |
HIGHER RISK: numerous findings in ACAM or ramp
inspections MEDIUM RISK: few findings in ACAM inspections LOWER RISK: rare findings in ACAM inspections |
|
System redundancy |
HIGHER RISK: single-engined aircraft LOWER RISK: multi-engined aircraft |
|
Supplementary maintenance measures |
HIGHER RISK: no supplementary measures LOWER RISK: supplementary measures (such as oil
analysis, engine data monitoring, boroscope inspections, corrosion
inspections, etc.) |
|
Risk factor of the component failure |
HIGHER RISK: engine failure on a helicopter MEDIUM RISK: engine failure on an aeroplane LOWER RISK: sailplane, or powered sailplane |
The above
information may be useful for CAMOs and CAOs when developing and approving
maintenance programmes, and for the AR staff performing ARs and reviewing the
effectiveness of the declared maintenance programme. It may also be useful for
the owner in order to take an informed decision before introducing deviations
from the DAH’s recommendations. Nevertheless, as allowed by ML.A.302(c)(7) and explained in GM ML.A.302, when the owner issues a declaration for
the maintenance programme, they do not need to justify such deviations.
When creating or modifying aircraft maintenance programs, a risk-based approach is crucial, especially when deviating from manufacturer recommendations. Factors like operational approval, flight rules, aircraft weight, maintenance management, time in service, utilization, inspection findings, system redundancy, and component failure risks must be considered. Owners introducing deviations don't need to justify them when issuing a declaration for the maintenance program.
* Summary by Aviation.Bot - Always consult the original document for the most accurate information.
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