Appendix IV - Class and Ratings System to be used for the terms of Approval of Maintenance Organisations referred to in Annex I (Part-M) Subpart F
SI No. 588/2023
1. Except as stated otherwise for the smallest organisations referred to in point (11), the table in point (12) provides for the standard system for the approval of a maintenance organisation referred to in Annex I (Part-M), Subpart F. An organisation must be granted an approval that ranges from a single class and rating with limitations to all classes and ratings with limitations.
2. In addition to the table referred to in point (12), the approved maintenance organisation must indicate its scope of work in its maintenance organisation manual.
3. Within the approval class(es) and rating(s) granted by the CAA, the scope of work specified in the maintenance organisation exposition defines the exact limits of approval. It is therefore essential that the approval class(es) and rating(s) and the organisations scope of work are matching.
4. A category A class rating means that the approved maintenance organisation may carry out maintenance on the aircraft and any component (including engines and/or Auxiliary Power Units (APUs), in accordance with aircraft maintenance data or, if agreed by the CAA, in accordance with component maintenance data, only whilst such components are fitted to the aircraft. Nevertheless, such A-rated approved maintenance organisation may temporarily remove a component for maintenance, in order to improve access to that component, except when such removal generates the need for additional maintenance not eligible for the provisions of this point. This will be subject to a control procedure in the maintenance organisation exposition to be approved by the CAA. The limitation section will specify the scope of such maintenance thereby indicating the extent of approval.
5. A category B class rating means that the approved maintenance organisation may carry out maintenance on the uninstalled engine and/or APU and engine and/or APU components, in accordance with engine and/or APU maintenance data or, if agreed by the CAA, in accordance with component maintenance data, only whilst such components are fitted to the engine and/or APU. Nevertheless, such B-rated approved maintenance organisation may temporarily remove a component for maintenance, in order to improve access to that component, except when such removal generates the need for additional maintenance not eligible for the provisions of this point. The limitation section will specify the scope of such maintenance thereby indicating the extent of approval. A maintenance organisation approved with a category B class rating may also carry out maintenance on an installed engine during ‘base’ and ‘line’ maintenance subject to a control procedure in the maintenance organisation exposition to be approved by the CAA. The maintenance organisation exposition scope of work shall reflect such activity where permitted by the CAA.
6.A category C class rating means that the approved maintenance organisation may carry out maintenance on uninstalled components (excluding engines and APUs) intended for fitment to the aircraft or engine/APU. The limitation section will specify the scope of such maintenance thereby indicating the extent of approval. A maintenance organisation approved with a category C class rating may also carry out maintenance on an installed component during base and line maintenance or at an engine/APU maintenance facility subject to a control procedure in the maintenance organisation exposition to be approved by the CAA. The maintenance organisation exposition scope of work shall reflect such activity where permitted by the CAA.
7. A category D class rating is a self contained class rating not necessarily related to a specific aircraft, engine or other component. The D1 — Non Destructive Testing (NDT) rating is only necessary for an approved maintenance organisation that carries out NDT as a particular task for another organisation. A maintenance organisation approved with a class rating in A or B or C category may carry out NDT on products it is maintaining subject to the maintenance organisation exposition containing NDT procedures, without the need for a D1 class rating.
8. The limitation section is intended to give the CAA the flexibility to customise the approval to any particular organisation. Ratings must be mentioned on the approval only when appropriately limited. The table referred to in point (12) specifies the types of limitation possible. Whilst maintenance is listed last in each class rating it is acceptable to stress the maintenance task rather than the aircraft or engine type or manufacturer, if this is more appropriate to the organisation (an example could be avionic systems installations and related maintenance). Such mention in the limitation section indicates that the maintenance organisation is approved to carry out maintenance up to and including this particular type or task.
9. Where reference is made to series, type and group in the limitation section of class A and B, “series” means a specific type series such as Cessna 150, Cessna 172, Beech 55 series or Continental O-200 series; “type” means a specific type or model such as 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.
10. Where a lengthy capability list is used which could be subject to frequent amendments, then such amendments may be performed in accordance with the indirect approval procedure referred to in points M.A.604(c) and M.B.606(c).
11. A maintenance organisation which employs only one person to both plan and carry out all maintenance can only hold a limited scope of approval rating which may be further limited by the CAA depending on the capability of the particular organisation. The maximum permissible limits are:
| CLASS | RATING | LIMITATION |
|---|---|---|
| CLASS AIRCRAFT | RATING A2 AEROPLANES 5700 KG AND BELOW | PISTON ENGINE 5700 KG AND BELOW |
| CLASS AIRCRAFT | RATING A3 HELICOPTERS | SINGLE PISTON ENGINE 3175 KG AND BELOW |
| CLASS AIRCRAFT | RATING A4 AIRCRAFT OTHER THAN A1, A2 AND A3 | NO LIMITATION |
| CLASS ENGINES | RATING B2 PISTON | LESS THAN 450 HP |
| CLASS COMPONENTS RATING OTHER THAN COMPLETE ENGINES OR APU’S. | C1 TO C22 | AS PER CAPABILITY LIST |
| CLASS SPECIALISED | D1 NDT | NDT METHOD(S) TO BE SPECIFIED. |
It should be noted that such an organisation may be further limited by the CAA in the scope of approval dependent upon the capability of the particular organisation.
12. Table
| CLASS | RATING | LIMITATION | BASE | LINE |
|---|---|---|---|---|
| AIRCRAFT | A2 Aeroplanes 5700 kg and below |
Shall state aeroplane manufacturer or group or series or type and/or the maintenance tasks Example: DHC-6 Twin Otter Series State whether the issue of airworthiness review certificates is authorised or not |
YES/NO | YES/NO |
| A3 Helicopters |
Shall state helicopter manufacturer or group or series or type and/or the maintenance task(s) Example: Robinson R44 |
YES/NO | YES/NO | |
| A4 Aircraft other than A1, A2 and A3 |
[Shall state aircraft category (sailplane, balloon, airship, etc.), manufacturer or group or series or type and/or the maintenance task(s)] State whether the issue of airworthiness review certificates is authorised or not |
YES/NO | YES/NO | |
| ENGINES | B1 Turbine |
Shall state engine series or type and/or the maintenance task(s) Example: PT6A Series |
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| B2 Piston |
Shall state engine manufacturer or group or series or type and/or the maintenance task(s) | |||
| B3 APU |
Shall state engine manufacturer or series or type and/or the maintenance task(s) | |||
| COMPONENTS OTHER THAN COMPLETE ENGINES OR APUs | C1 Air Cond & Press |
[Shall state aircraft type or aircraft manufacturer or component manufacturer or the particular component and/or cross refer to a capability list in the exposition and/or the maintenance task(s).] Example: PT6A Fuel Control |
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| C2 Auto Flight |
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| C3 Comms and Nav |
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| C4 Doors — Hatches |
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| C5 Electrical Power & Lights |
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| C6 Equipment |
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| C7 Engine — APU |
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| C8 Flight Controls |
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| C9 Fuel |
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| C10 Helicopter — Rotors |
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| C11 Helicopter — Trans |
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| C12 Hydraulic Power |
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| C13 Indicating — recording system |
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| C14 Landing Gear |
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| C15 Oxygen |
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| C16 Propellers |
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| C17 Pneumatic & Vacuum |
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| C18 Protection ice/rain/fire |
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| C19 Windows |
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| C20 Structural |
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| C21 Water ballast |
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| C22 Propulsion Augmentation |
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| SPECIALISED SERVICES | D1 Non Destructive Testing |
Shall state particular NDT method(s) |
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