Airworthiness Directive 2021-24-15
one-timeAirworthiness Directives; Bell Textron Canada Limited Helicopters
What this AD requires
The FAA is adopting a new airworthiness directive (AD) for Bell Textron Canada Limited Model 206L-1, 206L-3, and 206L-4 helicopters with certain Air Comm Corporation air conditioning systems installed. This AD was prompted by reports of damage to the drive ring spline teeth and the mating spline teeth. This AD requires visually inspecting the drive ring spline teeth and the mating area spline teeth on the oil cooler blower shaft for signs of deformation and fretting and depending on the results of the inspection, removing certain parts from service. This AD also requires reinstalling certain parts, applying torque, and aligning certain bolt holes. The FAA is issuing this AD to address the unsafe condition on these products.
Which aircraft AD 2021-24-15 applies to
Applies to (1) Model 206L-1 and 206L-3 helicopters (206L-1+/206L-3+ designations treated the same) with Bell Service Instruction BHT-206-SI-2052, Revision 1, installed, and (2) Model 206L-4 helicopters; in both cases equipped with an Air Comm Corporation air conditioning system (STC SH2750NM) of one of the listed part numbers.
Whether AD 2021-24-15 actually applies to your aircraft (by serial and installed parts) and whether it’s already complied with comes from that aircraft’s records.
How AD compliance is recorded
A valid compliance record (14 CFR 43.9) states:
Tailplate reads a tail number’s logbooks and matches every applicable AD — including this one — to its compliance evidence, with recurring next-due dates computed.
Look up a tail number →Read the full directive (Federal Register)Applicability is derived from the FAA directive corpus and is advisory, not a legal airworthiness determination. Compliance is established only from an aircraft’s actual records.