Commonwealth legislation

AD/AC-SNOW/17 - Outer Wing Huck Bolts

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Commonwealth

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legislative instrument

Plain English Summary

3/10 complexity

This Airworthiness Directive requires operators of specified Ayres Thrush (Snow) Commander aeroplanes to carry out repetitive inspections of outer-wing Huck bolts under Ayres Service Bulletin SB-AG-33 and to replace existing aluminium Huck bolts with steel Huck bolts or NAS bolts within set flight‑hour limits (Applicability; Requirement; Background). Operators must pay for and schedule the work: inspections start within 10 hours and recur every 100 hours until replacement, and replacement must occur within 500 hours after 18 March 1993 (Compliance).

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AD/AC-SNOW/17 - Outer Wing Huck Bolts

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Ayres Thrush (Snow) Commander Series Aeroplanes

AD/AC-SNOW/17 Outer Wing Huck Bolts 5/93 DM

Applicability: Models and serial numbers as listed in the Requirement Document. Requirement: Action in accordance with Ayres Corporation Service Bulletin SB-AG-33,

Accomplishment Instructions Parts I and II.

Compliance: For Part I: Initially, within 10 hours’ time in service after 18 March 1993 and thereafter at intervals not to exceed 100 hours’ time in service; until Accomplishment Instruction Part II, is complied with.

For Part II: Within 500 hours’ time in service after 18 March 1993.

Background: A recent report was received from a local operator of sheared Huck bolts on the outer section of both wing upper spar caps. Additionally, the LH spar web was found creased at WS 183 upper. The Manufacturer has determined that progressive fastener failure from the wing tip towards the root is a catastrophic mode of failure and must be prevented from starting. This Directive requires on-going repetitive inspections until the existing aluminium Huck bolts are replaced with steel Huck bolts or NAS bolts.

Source text

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

1 AD/AC-SNOW/17 - Outer Wing Huck Bolts