Engine Manual) or, if agreed by the competent authority, in accordance with component maintenance data, only whilst such components are fitted to the engine and/or APU (unless exception below described).
Indeed, 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 (e.g. The Category B Organisation is logically very similar to the one above described (Category A). Category “B” class rating (Engines & APUs) The rating A1 refers to large aircraft (above 5700 Kg), A2 refers to aircraft equal and below 5700 kg, A3 refers to helicopters and A4 refers to aircraft others than A1, A2 and A3.
In some exceptional case, the competent authority may agree the use of a Component Maintenance Manual, in accordance with an agreed procedure which normally aims to ensure that the A-rated Organisation has the capability to carry out something supposed to be done at a specific shop.
ATA CHAPTER 79 MANUALS
The manuals allowed to be used for a Category A Organisation are the Aircraft Maintenance Data only, like AMM (Aircraft Maintenance Manual), SRM (Structural Repair Manual) and Service Bulletins applicable to the aircraft, just to mention a few. If the component needs instead to be removed in order to be maintained, then it should be sent to a specific shop (e.g to an Engine shop or to a component shop), unless it falls within the exceptions below described. an engine, a landing gear a structural part), can be maintained whilst it is still fitted to the aircraft then, the A rated Organisation can also carry out maintenance on such component.
So this is the class rating hold by many Organisations on the need to carry out maintenance at the airport’s tarmac for example (which is called “Line Maintenance”) or within Hangars (which is called “Base Maintenance”). Let’s start by saying once more again that a class rating “A” refers to the possibility (for the Organisation with such a rating), to carry out maintenance on aircraft. Let us delve in some more detail: Category “A” class rating (Aircraft) Such ratings simply identify what the Organisation is approved for and while A, B and C refers to authorization to carry out maintenance on aircraft, engines and components respectively, the D rating is authorization to carry out and release in an EASA Form 1 “Non Destructive Tests” (NDT) only.