Commonwealth legislation

AD/BELL 47/91 - Tail Rotor Blade Assembly P/N 47-642-117-1 - Replacement

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This Act has been repealed and is no longer in force. It is retained for historical reference.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

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What this is: A mandatory safety order (called an Airworthiness Directive) issued by the Civil Aviation Safety Authority requiring helicopter operators to replace faulty tail rotor blades.

Who it affects: Owners and operators of all Bell 47 series helicopters.

What you must do:

Replace tail rotor blade assemblies with part number 47-642-117-1 and serial numbers between A-8 and A-72
Do this within 100 hours of flight time after 31 January 1985, or at your next scheduled maintenance inspection — whichever comes later

Why this matters: The manufacturer discovered dangerous gaps (called "bonding voids") in the blade roots during testing. These defects could cause the tail rotor to fail, potentially leading to loss of control of the helicopter.

Reference: You must follow the manufacturer's Alert Service Bulletin 47-84-11 when doing the replacement.

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Current sections

Direct links to the current provisions in AD/BELL 47/91 - Tail Rotor Blade Assembly P/N 47-642-117-1 - Replacement.

AD/BELL 47/91 - Tail Rotor Blade Assembly P/N 47-642-117-1 - Replacement

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

View image in the official source Bell Helicopter Textron 47 (All Variants) Series Helicopters

AD/BELL 47/91 Tail Rotor Blade Assembly P/N 47-642-117-1 - Replacement

Applicability: All models. Requirement Document Bell Helicopter Alert S.B. 47-84-11.

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Compliance: Within 100 hours time in service after 31 January 1985 or at the next scheduled inspection for maintenance release issue. Whichever is the later.

Background: The manufacturer advises that bonding voids may have occurred in the root areas of tail rotor blade assemblies, S/Nos A-8 through A-72. A bonding void was found during periodic destructive testing.

Source text

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