FAQ n.142042

In case an appropriately rated approved maintenance organisation (AMO) intends to ‘overhaul’ a component (including engine), it should hold the applicable maintenance data for the particular component to be maintained (in the rest of this FAQ, “the maintenance data”) and ensure the following:

1. If the overhaul process is defined in the maintenance data (e.g. in the CMM), the AMO must follow it in full. At the completion of the process, the AMO can then issue the EASA Form 1 with "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 cases, both subject to the conditions that the maintenance data specifies tolerances and/or dimensional information against which the component can be evaluated and that the maintenance data contains repair solutions to address the potential defects/excessive wear of the components:
   1. If the component can be disassembled, the component maintenance can only be released with the entry “overhauled” when:
      • the component undergoes the full extent of the disassembly, cleaning, inspection, reassembly and testing tasks specified in the maintenance data; and
      • in case of detected defects, the component undergoes all associated repairs specified in the maintenance data.
   2. If a disassembly cannot be accomplished without causing damage (i.e. single-piece component), the component maintenance can only be released with the entry “overhauled” when:
      • the component undergoes the full extent of the cleaning, inspection and testing tasks specified in the maintenance data;
      • and in case of detected defects, the component undergoes all associated repairs specified in the maintenance data.

In case 2), this means that if inspections and/or testing tasks conclude that the component contains a defect within acceptable tolerance specified in the maintenance data and this defect is not repaired, the maintenance should be released under ‘inspected/tested’.

In all cases, the AMO must clearly describe in Block 12 of the EASA Form 1 the maintenance actions performed to achieve the “overhauled” status, and the reference to the sections/chapter(s) of the maintenance data used.

Importantly, “Maintenance data” is defined in point M.A.401(b) of Annex I (Part-M) to Regulation (EU) No 1321/2014 and in the case of component intended for overhaul, has to be specific to component to be maintained: it can be either issued by the design approval holder of the design to which the component belongs or published by the manufacturer of the component if this data is acceptable to the design approval holder. If specific maintenance data exists for a given component (e.g. from the component manufacturer), such maintenance data cannot be replaced by maintenance data from a higher-level element (e.g. aircraft or engine to which the component belongs) for the purpose of overhauling the component.

For particular cases beyond the general scope of this FAQ, the maintenance organisation should seek agreement with its competent authority about the most appropriate entry for block 11.

For reference:

Paragraph 5, block 11 of Appendix II to Annex I (Part-M) of Regulation (EU) No 1321/2014:

“Block 11 Status/Work

The following describes the permissible entries for block 11. Enter only one of these terms — where more than one may be applicable, use the one that most accurately describes the majority of the work performed and/or the status of the article.

1. Overhauled means a process that ensures the item is in complete conformity with all the applicable service tolerances specified in the type certificate holder's, or equipment manufacturer's instructions for continued airworthiness, or in the data which is approved or accepted by the Authority. The item will be at least disassembled, cleaned, inspected, repaired as necessary, reassembled and tested in accordance with the above specified data ’’

M.A.401 Maintenance data

“[…] (b) […] applicable maintenance data is any of the following:

1. any applicable requirement, procedure, standard or information issued by the competent authority or the Agency;
2. any applicable airworthiness directive;
3. the applicable instructions for continuing airworthiness and other maintenance instructions, issued by the type-certificate holder, […]
4. for components approved for installation […], the applicable maintenance instructions published by the component manufacturers and acceptable to the design approval holder […]
5. any applicable data issued in accordance with point 145.A.45(d).’’