The FAA is adopting a new airworthiness directive (AD) for all GE Aviation Czech M601D-11 model turboprop engines. This AD was prompted by the manufacturer revising the airworthiness limitations section (ALS) of the existing engine maintenance manual (EMM) to include a visual inspection of the centrifugal compressor case for cracks (see Figure 1 below). This AD may be performed by the owner/operator (pilot) holding at least a private pilot certificate and must be entered into the aircraft records showing compliance. Action is required within 90 days after the effective date of the AD, which is Aug. 1, 2022.
The complete AD is available here. NAAA reported on this as a proposed AD in the April 21, 2022 eNewsletter.