Summary
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 done, and prohibits using certain paint strippers. The FAA is issuing this AD to address the unsafe condition on these products.
Directive Details
AD Number
FAA-2024-2555
Document Number
2025-15839
Type
Rule
Publication Date
August 20, 2025
Effective Date
September 24, 2025
Affected Manufacturer
Siam Hiller Holdings, Inc.
Criticality
routine
Emergency
No
Docket ID
Docket No. FAA-2024-2555
Topics
Official Documents
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