Siam hiller holdings airworthiness directives
2 ADs in the reference matching Siam hiller holdings — from the Federal Register, checked every weekday. Applicability may depend on serial and effectivity: verify against the official AD before any maintenance action.
Reference last synced: 10/23/2026 04:00 UTC · 10,462 ADs indexed
Airworthiness Directives; Siam Hiller Holdings, Inc.
The FAA is adopting a new airworthiness directive (AD) for certain Siam Hiller Holdings, Inc. (Siam Hiller), Model UH-12E (Army OH-23G and H-23F) and UH-12E-L helicopters. This AD was prompted by reports of cracks found in a main rotor (M/R) transmission drive shaft (drive shaft). This AD requires inspecting certain M/R drive shafts for a crack, prohibits installing certain M/R drive shafts unless the inspection is…
Airworthiness 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
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 amendme…