Commonwealth legislation

AD/LYC/83 - Crankshaft Flange

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Commonwealth

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legislative instrument

Plain English Summary

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Requires operators and owners of specified Lycoming 540‑series engines used in "unlimited" aerobatic manoeuvres (or engines converted for aerobatics) to visually inspect the crankshaft flange in accordance with Lycoming Service Bulletin No. 482. (Requirement)

Inspections must occur initially within 100 hours of operation after 3 November 1988 for engines already used in unlimited manoeuvres and thereafter at intervals not exceeding every 10 hours of unlimited aerobatic flight. Costs and recordkeeping fall to the aircraft owner/operator; compliance imposes frequent inspections and maintenance actions. (Compliance)

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Current sections

Direct links to the current provisions in AD/LYC/83 - Crankshaft Flange.

AD/LYC/83 - Crankshaft Flange

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Lycoming Piston Engines

AD/LYC/83 Crankshaft Flange 11/88

Applicability: All AEIO-540-D series, IO-540 (250 & 260 horsepower) engines converted for aerobatic flight or any other 540 engines employing a 2-3/8 diameter main bearing seal used in unlimited category aerobatic manoeuvres.

Requirement: Visually inspect the crankshaft flange in accordance with Lycoming Service Bulletin No 482.

Compliance: For those engines which have been subjected to unlimited category manoeuvres - initially within 100 hours of engine operation after 3 November 1988 and thereafter at intervals not exceeding each 10 hours of aerobatic flight involving unlimited category manoeuvres.

Background: Lycoming SB 482 advises that cracked crankshafts have occurred on applicable engines which have been submitted to unlimited category aerobatic manoeuvres. These manoeuvres are more severe than contemplated when the engines were certificated for prolonged inverted flight and for normal aerobatic manoeuvres. Unlimited category manoeuvres such as multiple snap rolls, inverted flat spins, lomcevaks etc. produce severe bending loads on the propeller flange area. Exceeding engine maximum rated speed and/or using the aircraft in manoeuvres which produce rapid angular propeller centreline acceleration may result in crankshaft failure.

Source text

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

1 AD/LYC/83 - Crankshaft Flange

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

Lycoming Piston Engines

AD/LYC/83 Crankshaft Flange 11/88

Requirement: Visually inspect the crankshaft flange in accordance with Lycoming Service Bulletin No 482.