Appendix II — Class and rating system for the terms of approval of Part-145 maintenance organisations

(a)     Except as stated otherwise for the smallest organisations referred to in point (m), the table referred to in point (l) provides the possible classes and ratings to be used to establish the terms of approval of the certificate of the organisation approved in accordance with Annex II (Part-145). An organisation must be granted terms of approval that range from a single class and rating with limitations to all classes and ratings with limitations.

(b)     In addition to the table in point (l), each maintenance organisation is required to indicate its scope of work in its MOE.

(c)      Within the approval class(es) and rating(s) established by the competent authority, the scope of work specified in the MOE defines the exact limits of its approval. It is therefore essential that the approval class(es) and rating(s) and the organisation’s scope of work match.

(d)     A category A class rating means that the maintenance organisation may carry out maintenance on aircraft and components (including engines and/or auxiliary power units (APUs)), in accordance with the aircraft maintenance data or, if agreed by the competent authority, in accordance with the component maintenance data, only while such components are fitted to the aircraft. Nevertheless, such an A-rated maintenance organisation may temporarily remove a component for maintenance in order to improve access to that component, except when its removal generates the need for additional maintenance that the organisation is not approved to perform. Such removal of component for maintenance by A-rated maintenance organisation shall be subject to an appropriate control procedure in the MOE.

The limitation column must specify the scope of such maintenance, thereby indicating the extent of the approval.

(e)     Category A class ratings are subdivided into “Base” or “Line” maintenance categories. Such an organisation may be approved for either “Base” or “Line” maintenance, or both. It should be noted that a “Line” facility located at a main base facility requires a “Line” maintenance approval.

(f)      A category B class rating means that the maintenance organisation may carry out maintenance on uninstalled engines and/or APUs and engine and/or APU components, in accordance with the engine and/or APU maintenance data or, if agreed by the competent authority, in accordance with the component maintenance data, only while such components are fitted to the engine and/or the APU. Nevertheless, such a B-rated approved maintenance organisation may temporarily remove a component for maintenance in order to improve access to that component, except when its removal generates the need for additional maintenance that the organisation is not approved to perform.

The limitation column must specify the scope of such maintenance, thereby indicating the extent of the approval.

A maintenance organisation that is approved with a category B class rating may also carry out maintenance on an installed engine during aircraft base and line maintenance, provided that an appropriate control procedure in the MOE has been approved by the competent authority. The scope of work in the MOE shall reflect those activities if they are permitted by the competent authority.

(g)     A category C class rating means that the maintenance organisation may carry out maintenance on uninstalled components (excluding complete engines and APUs) that are intended to be fitted on the aircraft or the engine/APU.

The limitation column must specify the scope of such maintenance, thereby indicating the extent of the approval.

A maintenance organisation that is approved with a category C class rating may also carry out maintenance on an installed component (other than a complete engine/APU) during aircraft base and line maintenance, or at an engine/APU maintenance facility provided that an appropriate control procedure in the MOE has been approved by the competent authority. The scope of work in the MOE shall reflect those activities if they are permitted by the competent authority.

(h)     A category D class rating is a self-contained class rating that is not necessarily related to a specific aircraft, engine or other component. The D1 – Non-Destructive Testing (NDT) rating is only necessary for a maintenance organisation that carries out NDT as a particular task for another organisation. A maintenance organisation that is approved with a class rating in the A, B or C category may carry out NDT on products that it maintains without the need for a D1 class rating provided that the MOE contains appropriate NDT procedures.

(i)      The limitation column is intended to give competent authorities the flexibility to customise an approval for any particular organisation. Ratings may only be mentioned on the approval if they are appropriately limited. The table in point (l) specifies the types of limitations that are possible. It is acceptable to stress in the limitation column the maintenance task rather than the type or manufacturer of the aircraft or engine, if that is more appropriate to the organisation (an example could be avionics systems installations and the related maintenance). If that is mentioned in the limitation column, it indicates that the maintenance organisation is approved to carry out maintenance up to and including that particular type/task.

(j)      When reference is made to the series, type and group in the limitation column of class A and B, it shall be understood as follows:

—      “series” means a specific type series such as the Airbus 300, 310 or 319, or the Boeing 737-300 series, the RB211-524 series, the Cessna 150 or Cessna 172, the Beech 55 series, the continental O-200 series, etc.,

—      “type” means a specific type or model such as the Airbus 310-240 type, the RB 211-524 B4 type, or the Cessna 172RG type.

Any number of series or types may be quoted,

—      “group” means, for example, Cessna single piston engine aircraft or Lycoming non-supercharged piston engines, etc.

(k)     By way of derogation from point 145.A.85(a)(1), when a component capability list is used that could be subject to frequent amendments, then the organisation may propose to include such amendments in the procedure referred to in point 145.A.85(c) for changes not requiring prior approval.

(l)      Table

(m)    A maintenance organisation which employs only one person to both plan and carry out all its maintenance activities can only hold limited terms of approval. The maximum permissible limits are as follows:

It should be noted that such an organisation may be further limited by the competent authority in the terms of approval depending on the capabilities of the particular organisation.