Commonwealth legislation

AD/DHC-6/67 - Lower Skin and L/E Rivets at Front Spar

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Commonwealth

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legislative instrument

Plain English Summary

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Requires operators of DHC-6 (Twin Otter) aeroplanes that do not already have Mod 6/1645 and Mod 6/1893 to inspect the lower skin and leading-edge rivets at the front spar, repair defective or missing rivets, and install the specified modifications within short, fixed time windows. It matters because corrosion was found on rivet heads in that joint; losing the rivets would destroy the joint’s structural integrity, so operators pay for inspections, repairs and mandated modifications to restore airworthiness.

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Current sections

Direct links to the current provisions in AD/DHC-6/67 - Lower Skin and L/E Rivets at Front Spar.

AD/DHC-6/67 - Lower Skin and L/E Rivets at Front Spar

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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DHC-6 (Twin Otter) Series Aeroplanes

AD/DHC-6/67 Lower Skin and L/E Rivets at Front Spar 1/94

Applicability: Model DHC-6 aircraft that do not have Modifications 6/1645 and 6/1893 incorporated.

Requirement: 1. Carry out a detailed visual inspection in accordance with Part A of de Havilland Service Bulletin 6/517.

If any unserviceable rivets are found, proceed in accordance with Part C of Service Bulletin 6/517.

In addition, if four or more rivets in the joint are missing or defective, proceed in accordance with Part B of Service Bulletin 6/517.

2. Carry out the following modifications in accordance with Part C of Service Bulletin 6/517:

On aircraft up to and including serial number 580, incorporate Modification 6/1645.

b. On all aircraft, incorporate Modification 6/1893.

Note: Transport Canada AD CF-93-25 refers.

Compliance: 1. Within 500 hours time in service after 6 January 1994, or prior to 6 April 1994, whichever occurs first.

Prior to 6 July 1994.

Background: Corrosion has been found on the heads of the rivets attaching the wing lower and leading edge skins to the front spar flanges in the area between the landing light and the engine nacelle. Loss of these rivets will destroy the structural integrity of the joint.

Source text

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

1 AD/DHC-6/67 - Lower Skin and L/E Rivets at Front Spar