The FAA is adopting a new airworthiness directive (AD) for certain GE Aviation Czech (formerly Walter) M601E–11AS, M601E‐11S, H75–100, H80–100 and H85–100 model turboprop engines. These engines are known to be installed on Air Tractor AT-400 and AT-500 series; Allied Ag Cat Productions Inc. (formerly Grumman) G-164 series; and Thrush Aircraft (formerly Quality, Ayres, Rockwell) 510G and S-2R series.
This AD was prompted by reports of multiple failures of the needle bearing installed in propeller governors having part numbers (P/Ns) P–W11–1 or P–W11–2, caused by self-generated debris from the needle bearing, which led to oil contamination.
This AD requires replacing the affected propeller governors with a redesigned propeller governor with P/N P–W11–4 or P–W11–5.
Compliance with this AD for affected engines is required by April 15, 2026. View the complete AD here.
 M601E–11AS, M601E‐11S, H75–100, H80–100
and H85–100 model turboprop engines. These engines are known to be
installed on Air Tractor AT-400 and AT-500 series; Allied Ag Cat
Productions Inc. (formerly Grumman) G-164 series; and Thrush Aircraft
(formerly Quality, Ayres, Rockwell) 510G and S-2R series.){kind=small}
