APPENDIX II CLASS AND RATING SYSTEM FOR THE TERMS OF APPROVAL OF PART-145 MAINTENANCE ORGANISATIONS

SI No. 1290/2024

(a) Except as stated otherwise for the smallest organisations referred to in point (m), the table 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 classes and ratings established by the CAA, the scope of work specified in the MOE defines the exact limits of its approval. It is therefore essential that the approval classes and ratings 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, auxiliary power units (APUs) or both), in accordance with the aircraft maintenance data or, if agreed by the CAA, 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 must be subject to an appropriate control procedure in the MOE. The limitation column must specify the scope of such maintenance in order to indicate 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, APUs and engines, APU components or a combination of them, in accordance with the engine or APU maintenance data or both, or, if agreed by the CAA, in accordance with the component maintenance data, only while such components are fitted to the engine, the APU or both. 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 CAA. The scope of work in the MOE must reflect those activities if they are permitted by the CAA.

(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 or 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 or APU) during aircraft base and line 53 maintenance, or at an engine or APU maintenance facility provided that an appropriate control procedure in the MOE has been approved by the CAA. The scope of work in the MOE must reflect those activities if they are permitted by the CAA.

(h) A “category D class rating” means 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 the CAA 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 or task.

(j) When reference is made to the series, type and group in the limitation column of class A and B, it must be understood as follows: “series” means a specific type series such as the Airbus 300, 310, 319, the Boeing 737-300 series, RB211-524 series, Cessna 150, Cessna 172, Beech 55 series or the Continental O-200 series; “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 nonsupercharged piston engines, etc.

(k) By way of derogation from point 145.A.85, where 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.70(a)(10) for changes not requiring prior approval.

(l) Limitation

CLASS	RATING	LIMITATION	BASE	LINE
AIRCRAFT	A1 Aeroplanes above 5,700kg maximum take- off mass (MTOM)	[Must state the aeroplane manufacturer or the group or series or type and/or the maintenance tasks] Example: Airbus A320 Series	[YES/NO](*)	[YES/NO](*)
	A2 Aeroplanes of 5,700kg MTOM and below	[Must state the aeroplane manufacturer or the group or series or type and/or the maintenance tasks] Example: DHC-6 Twin Otter Series State whether the issuing of airworthiness review certificates is authorised (only possible for aircraft covered by Annex 5b (Part-ML))	[YES/NO](*)	[YES/NO](*)
	A3 Helicopters	[Must state the helicopter manufacturer or the group or series or type and/or the maintenance task(s)] Example: Robinson R44 State whether the issuing of airworthiness review certificates is authorised (only possible for aircraft covered by Annex 5b (Part-ML))	[YES/NO](*)	[YES/NO](*)
	A4 Aircraft other than A1, A2 and A3 aircraft	[Must state the aircraft category (sailplane, balloon, airship, etc.), the manufacturer or group or series or type and/or the maintenance task(s)] State whether the issuing of airworthiness review certificates is authorised (only possible for aircraft covered by Annex 5b (Part-ML))	[YES/NO](*)	[YES/NO](*)
ENGINES	B1 Turbine	[Must state the engine series or type and/or the maintenance task(s)] Example: PT6A Series
	B2 Piston	[Must state the engine manufacturer or group or series or type and/or the maintenance task(s)]
	B3 APU	[Must state the engine manufacturer or series or type and/or the maintenance task(s)]
COMPONENTS OTHER THAN COMPLETE ENGINES OR APUs	C1 Air Cond & Press	[Must state the 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
	C2 Auto Flight
	C3 Comms and Nav
	C4 Doors — Hatches
	C5 Electrical Power & Lights
	C6 Equipment
	C7 Engine – APU
	C8 Flight Controls
	C9 Fuel
	C10 Helicopter – Rotors
	C11 Helicopter – Trans
	C12 Hydraulic Power
	C13 Indicating – recording system
	C14 Landing Gear
	C15 Oxygen
	C16 Propellers
	C17 Pneumatic & Vacuum
	C18 Protection ice/rain/fire
	C19 Windows
	C20 Structural
	C21 Water ballast
	C22 Propulsion Augmentation
SPECIALISED SERVICES	D1 Non-Destructive Testing	[Must state particular NDT method(s)]
(*) Delete as appropriate.