Airworthiness Directive 2000-24-21
one-timeAirworthiness Directives; Siam Hiller Holdings, Inc. Model UH-12, UH-12A, UH-12B, UH-12C, UH-12D, UH-12E, UH-12E-L, UH-12L, and UH-12L4 Helicopters
What this AD requires
This amendment adopts a new airworthiness directive (AD), for Siam Hiller Holdings, Inc. (Hiller), formerly Rogerson Hiller Corporation, Model UH-12, UH-12A, UH-12B, UH-12C, UH-12D, UH-12E, UH- 12E-L, UH-12L, and UH-12L4 helicopters, that requires replacing all undrilled-shank bolts at pivoting joints in the control system linkage with drilled-shank bolts and installing castellated nuts and cotter pins. This amendment is prompted by an accident caused by separation of the control system linkage of a Model UH-12E helicopter. The actions specified by this AD are intended to prevent separation of the control system attachments at pivoting points and subsequent loss of control of the helicopter.
Which aircraft AD 2000-24-21 applies to
Requires replacing undrilled-shank bolts at control-system pivoting joints with drilled-shank bolts plus castellated nuts/cotter pins per Hiller Aircraft Corporation SB 10-4 Rev.2. Specific helicopter model designation not present in retrieved text segment (lead-in applicability paragraph not captured).
Whether AD 2000-24-21 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.