Commonwealth legislation

AD/AL 250/50 Amdt 1 - N2 Overspeed Control Assembly - Addition of Lockwashers to Ground Jumper Lead

RepealedCTH

This Act has been repealed and is no longer in force. It is retained for historical reference.

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Commonwealth

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legislative instrument

Plain English Summary

2/10 complexity

What this does: This is a mandatory safety directive (an Airworthiness Directive) requiring a specific hardware fix on certain aircraft turbine engines.

Who it affects: Owners and operators of aircraft powered by Allison 250-C28C and C30S model engines (commonly used in helicopters and light aircraft).

What must happen: Maintenance crews must install lockwashers (special washers that stop bolts vibrating loose) onto the ground jumper lead (an electrical earthing wire) attached to the N2 overspeed control assembly (the safety system that stops the engine from over-revving).

Why it matters: Without this fix, vibration can loosen the electrical connection, potentially causing the overspeed protection to fail or creating dangerous electrical faults.

What's changed: This amendment expands the directive to cover more engine models (adding the C30 series and clarifying coverage of C28C and C30S) while excluding specific engine serial numbers listed in the referenced technical bulletins.

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Direct links to the current provisions in AD/AL 250/50 Amdt 1 - N2 Overspeed Control Assembly - Addition of Lockwashers to Ground Jumper Lead.

AD/AL 250/50 Amdt 1 - N2 Overspeed Control Assembly - Addition of Lockwashers to Ground Jumper Lead

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COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

View image in the official source Allison Turbine Engines - 250 Series

AD/AL 250/50

Amdt 1

N2 Overspeed Control Assembly - Addition of Lockwashers to Ground Jumper Lead

1/83

Applicability: All model 250-C28C and C30S engines excepting those exempted in the documents.

Document: Allison 250-C28C, Alert CEB A73-2024, Rev. 2. Allison 250-C30S, Alert CEB A73- 3015, Rev. 2.

Compliance: As per the requirement document.

Background: This AD has been amended to include all Models 250-C28C, C30 and C30S, excepting the engine Serial Nos. specified in the document.

Source text

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