Commonwealth legislation

AD/HILLER 12/42 - Main Rotor Mast

RepealedCTH

This Act has been repealed and is no longer in force. It is retained for historical reference.

Jurisdiction

Commonwealth

Collection

legislative instrument

Plain English Summary

2/10 complexity

This rule requires owners and operators of Hiller UH-12 helicopters to urgently inspect the main rotor mast for cracks at the collective terminal-pin slots, with checks before the next flight (unless done within 100 flight hours), every 100 hours thereafter, and immediately if unusual vibration or stiff/binding collective controls occur. It responds to discovered cracks—one nearly through the mast—that could lead to catastrophic rotor separation and a crash.

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Current sections

Direct links to the current provisions in AD/HILLER 12/42 - Main Rotor Mast.

AD/HILLER 12/42 - Main Rotor Mast

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

View image in the official source
Hiller UH-12 Series Helicopters

AD/HILLER 12/42 Main Rotor Mast 6/91 DM

Applicability: All models.

Requirement: Perform a detailed visual inspection of the main rotor mast at both ends of the two elongated collective control terminal pin slots.

View image in the official source

Compliance: Prior to further flight unless accomplished within the previous 100 hours’ time in service, and thereafter at intervals not to exceed 100 hours’ time in service, and immediately upon the onset of any unusual vibration or any stiffness or binding of the collective control.

Background: Two aircraft have recently been reported as having cracks emanating from the ends of the elongated slots. One aircraft was reportedly cracked through 75% of its cross section while the other was reported to have two cracks 50 mm long. Indications in the worst affected aircraft included lateral and vertical vibration and stiffness and binding of the collective pitch control.

“Emergency Airworthiness Advice for Hiller UH-12 Helicopter” refers.

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

Source text

Sourced from the Federal Register of Legislation (legislation.gov.au), CC BY 4.0.

1 AD/HILLER 12/42 - Main Rotor Mast

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

Hiller UH-12 Series Helicopters

AD/HILLER 12/42 Main Rotor Mast 6/91 DM

Applicability: All models.

Requirement: Perform a detailed visual inspection of the main rotor mast at both ends of the two elongated collective control terminal pin slots.

“Emergency Airworthiness Advice for Hiller UH-12 Helicopter” refers.

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES