FAQ n.142042

For reference: “Overhaul is defined as a process ensuring that the item conforms fully to all applicable service tolerances specified by the type certificate (TC) holder, equipment manufacturer, or other data approved/accepted by the Authority. It requires at least disassembly, cleaning, inspection, repair as necessary, reassembly, and testing.” (Paragraph 5, Block 11 of Appendix II to Annex I (Part-M) of Regulation (EU) No 1321/2014).

In case the appropriately rated approved maintenance organisation (AMO) has received a clear work order for an overhaul and holds the applicable maintenance data for the part (e.g. Component Maintenance Manual (CMM), if available), the AMO may proceed with the overhaul if:

1. The original equipment manufacturer (OEM) defines an overhaul process in the maintenance data (e.g. in the CMM). In this case, the AMO must follow it as the primary reference. The AMO can then certify the component as "Overhauled" in Block 11, describing the maintenance actions carried out in Block 12.
2. If no overhaul process is defined in the maintenance data, there are two options:
   1. Apply the EASA definition of "overhaul" by dismantling, cleaning, inspecting, repairing (as necessary), reassembling, and testing the component; or
   2. When, for example, a full disassembly or testing is not possible without causing damage and there are service tolerances specified for the part/component by the TC holder, equipment manufacturer, Instructions for Continuing Airworthiness (ICAs), or other data approved/accepted by the Authority, perform all possible maintenance actions described in the available maintenance data.

We assume that, in either case, the AMO has ensured that the component meets all applicable service tolerances.

Therefore, under these conditions, it would be acceptable to certify the component as "Overhauled" in Block 11 of EASA Form 1.

It is worth noting that points "a" and "b" are effectively equivalent to an overhaul when the CMM already includes a sequence of disassembly, cleaning, inspection, repair (if necessary), reassembly, and testing, which mirrors the requirements of Appendix II to Part-M.

NB

• If a CMM exists for a certain part, and the AMO does not have access to it, the part cannot be released as "Overhauled" based only on other general documents such as an Engine Shop Manual (ESM).
• If a specific overhaul procedure is defined in the maintenance data but not fully followed, the part cannot be released as "Overhauled".
• In all cases, the AMO must clearly describe in Block 12 of EASA Form 1 the maintenance actions performed to achieve the "Overhauled" status, as well as the reference to the chapter(s) of the maintenance data used.