On Sept. 4, 2025, the FAA issued an Airworthiness Concern Sheet (ACS) for GE Aviation Czech (GEAC—formerly Walter Engines) turboprop engine Models H75-100 and -200, H80-100 and -200, M601D-11, M601E-11, -11A, -11AS, -11S and M601F. This ACS is in response to a European Union Aviation Safety Agency (EASA) Airworthiness Directive AD 2025-0022 that was issued on Jan 21, 2025.
The EASA AD was written to address possible delayed or lack of response to power inputs due to fuel deposits in the fuel control units (FCU). A mandatory lubricity improver additive (LIA) must be put in the aircraft fuel tanks every 100 hours.
While the FAA has not specifically proposed an AD, operators are encouraged to provide feedback to the FAA for analysis. Concerns related to availability of the required fuel additive at fueling stations, whether or not the recommendations of the original GEAC Alert Service Bulletin (ASB) SB-000469 Revision 01 are being followed, and any problems stemming from use of the additives are requested.
The ACS states, in part, “This Airworthiness Concern Sheet (ACS) is intended as a means for FAA Aviation Safety Engineers to coordinate airworthiness concerns with aircraft owners/operators through associations and type clubs. At this time, the FAA has not made a determination on what type of corrective action (if any) should be taken. The resolution of this airworthiness concern could involve Airworthiness Directive (AD) action or a Special Airworthiness Information Bulletin (SAIB), or the FAA could determine that no action is needed at this time. The FAA’s final determination will depend in part on the information received in response to this ACS.”
The FAA point of contact is Robert.D.Charbonneau@faa.gov
