What are the applicable ‘State of Design’ ADs for CFM International (CFM56, LEAP-1) engines?
Since CFM International engines (CFM56, and now also LEAP-1 engines) are jointly designed and manufactured by General Electric in the US and by SNECMA (now SAFRAN Aircraft Engines) in France, the situation is more complex than for other type designs. The FAA and EASA are joint State of Design authorities, both publish ADs, but do not adopt the other party’s ADs. FAA and EASA concluded a working arrangement, formalising the situation described above (in particular, see section 4.1.3).
Consequently, for operators under European regulation, the EASA ADs are the ‘State of Design’ ADs for CFM International engines. FAA ADs applicable to CFM International engines are not eligible for adoption in the EU system, unless EASA determines otherwise.
EASA can only consider adoption of FAA CFM International ADs in cases where the responsible design (change) approval holder is not CFM International, or where the unsafe condition was due to maintenance errors, e.g. FAA AD 2016-14-10 for P&W STC-modified engines; and AD 2009-11-02 for improper repair by PTLLC. In such cases, EASA has adopted these ADs and has informed EASA Member States to ensure operators are aware. The record in the EASA SP Tool provides the justification for EASA adoption of such FAA AD, recognised as ‘State of Design’ AD, not for the engine type design, but for the US-designed and FAA-certified STC, or the US-designed and FAA-certified repair, etc.
For non-EU States of Registry that have validated CFM International engine designs, it is the State of Registry (ICAO Annex 8, Chapter 4) that decides which are the applicable ADs – those issued by the FAA, or by EASA. Preferably, to avoid operator confusion, each State of Registry should determine which ADs they consistently (not on a case-by-case basis) adopt, either to follow FAA ADs, or EASA ADs.
Unfortunately, due to the differing EASA and FAA systems for creating ADs, there are cases where two corresponding ADs do not have identical requirements, as a result of which, compliance with an FAA AD may not be equal to compliance with the corresponding EASA AD, and vice versa. FAA and EASA are well aware that some operators face difficulties as they are sometimes expected to demonstrate compliance with both FAA and EASA CFM International ADs (e.g. aircraft/engines owned by a leasing company, or stipulated in an insurance contract). Unfortunately, conflicts can only be resolved by agreement from the State of Registry of the affected aircraft at the time compliance demonstration is warranted.