Commonwealth legislation

AD/S-76/54 - Main Gearbox Tail Takeoff Flange Locknut

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This Act has been repealed and is no longer in force. It is retained for historical reference.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

What this requires: Owners and operators of specific Sikorsky S-76 helicopters must inspect the locknut (a fastening device) on the main gearbox tail takeoff flange (the connection point between the main gearbox and the tail rotor drive shaft).

Why it matters: The locknut can lose its torque (tightness/grip), which could cause the tail rotor to fail in flight—a catastrophic safety risk.

Who is affected:

S-76A models: All helicopters fitted with main gearbox part number 76351-09500 series
S-76B models: Helicopters with main gearbox part number 76351-09600 series up to serial number A231-00038

What must be done: Operators must follow the specific inspection and testing procedures outlined in Sikorsky Alert Service Bulletin 76-66-23 and complete the work by 31 August 1989.

JSON API

Deep dive

Want the full deep dive?

Zoe can write the in-depth analysis on top of the summary above: how it works, who it affects and what each part actually does.

Current sections

Direct links to the current provisions in AD/S-76/54 - Main Gearbox Tail Takeoff Flange Locknut.

AD/S-76/54 - Main Gearbox Tail Takeoff Flange Locknut

meta-content-style-type: text/css meta-content-type: application/xhtml+xml; charset=utf-8 meta-generator: Aspose.Words for .NET 22.10.0

?xml version="1.0" encoding="utf-8" standalone="no"?>

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

View image in the official source Sikorsky S-76 Series Helicopters

AD/S-76/54 Main Gearbox Tail Takeoff Flange Locknut 7/89

Applicability: All S-76A helicopters fitted with P/N 76351-09500 series main gearboxes.

All S-76B helicopters fitted with P/N 76351-09600 series main gearbox up to and including S/N A231-00038.

Requirement: Action in accordance with Sikorsky Alert Service Bulletin 76-66-23. Compliance: By 31 August 1989.

Background: Due to torque loss of the tail takeoff flange locknut, specific tests to detect this torque loss are required.

Source text

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