Commonwealth legislation

AD/LA-4/10 Amdt 2 - Aircraft Structure - Inspection for Corrosion

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legislative instrument

Plain English Summary

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Revokes the prior AD and requires owners/operators of all Consolidated Aeronautics, Colonial and LA‑4 series aeroplanes to inspect aircraft structure and control push–pull rods for corrosion, following Lake Aircraft Service Letter No.25. It mandates rivet removal or rotation tests to detect hidden corrosion, replacement of corroded rivets, internal/external inspection of tubes and reassembly using approved data.

These inspections must occur at specified intervals or when corrosion is suspected, addressing corrosion that was found to have caused an in‑flight elevator control failure.

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Current sections

Direct links to the current provisions in AD/LA-4/10 Amdt 2 - Aircraft Structure - Inspection for Corrosion.

AD/LA-4/10 Amdt 2 - Aircraft Structure - Inspection for Corrosion

View image in the official source

View image in the official source
AIRWORTHINESS DIRECTIVE

On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/LA-4/10 Amdt 1 and issues the following AD under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

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Consolidated Aeronautics, Colonial and LA-4 Series Aeroplanes

AD/LA-4/10

Amdt 2

Aircraft Structure - Inspection for Corrosion 1/2005

Applicability: All models.

Requirement: 1. Inspect the aircraft structure in accordance with Lake Aircraft Service Letter No.25.

2. Inspect all control system push pull rods for corrosion. Where corrosion is suspected under rivet heads, one or more of the following methods may be used to determine if corrosion exists or the joint integrity has been lost:

Attempts should be made to remove the rivet heads by a light sharp blow with an aluminium tool made from bar stock with a blunt tip, or

b. If it is possible to rotate the control tube whilst the end fitting is held still, then rivet integrity is lost and all rivets are to be replaced.

3. When rivets in any control system push pull rod are to be replaced, then the following will apply:

All rivets are to be removed from the control push rod.

b. The control push rod tube and end fitting are to be internally and externally inspected for corrosion or damage and repaired as necessary.

c. Reassemble the control rod in accordance with approved data.

Note: It is recommended that during reassembly of push pull rods, a jointing compound be used to help protect the rivets in the joint from future corrosion.

Compliance: 1. Within 100 hours time in service after 30 April 1974 and thereafter at intervals not exceeding 1 year.

2. Within 100 hours time in service after 5 November 2003 and thereafter at intervals not exceeding 1 year.

3. If any rivets are found damaged or corroded.

This Amendment becomes effective on 20 January 2005.

Consolidated Aeronautics, Colonial and LA-4 Series Aeroplanes

AD/LA-4/10 Amdt 2 (continued)

Background: This amendment has been issued to correct the referenced requirements document from Service Bulletin No. 25 to Service Letter No.25.

Amendment 1 was issued as a result of extensive corrosion being found in an elevator control push rod joint after it failed in flight. Corrosion was not evident from an external visual inspection because it affected the tails of the rivets attaching the end fitting to the tube.

Initial issue of this Airworthiness Directive resulted from the Type Certificate holder advising of corrosion being found in critical structural elements of the aircraft.

Signature of David Villiers Delegate of the Civil Aviation Safety Authority

David Villiers

Delegate of the Civil Aviation Safety Authority 30 November 2004

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The above AD is notified in the Commonwealth of Australia Gazette on 22 December 2004.

Source text

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

1 AD/LA-4/10 Amdt 2 - Aircraft Structure - Inspection for Corrosion

AIRWORTHINESS DIRECTIVE

Consolidated Aeronautics, Colonial and LA-4 Series Aeroplanes

AD/LA-4/10

Amdt 2

Aircraft Structure - Inspection for Corrosion 1/2005

Applicability: All models.

Requirement: 1. Inspect the aircraft structure in accordance with Lake Aircraft Service Letter No.25.

2. Inspect all control system push pull rods for corrosion. Where corrosion is suspected under rivet heads, one or more of the following methods may be used to determine if corrosion exists or the joint integrity has been lost:

Attempts should be made to remove the rivet heads by a light sharp blow with an aluminium tool made from bar stock with a blunt tip, or

b. If it is possible to rotate the control tube whilst the end fitting is held still, then rivet integrity is lost and all rivets are to be replaced.

3. When rivets in any control system push pull rod are to be replaced, then the following will apply:

All rivets are to be removed from the control push rod.

b. The control push rod tube and end fitting are to be internally and externally inspected for corrosion or damage and repaired as necessary.

c. Reassemble the control rod in accordance with approved data.

Note: It is recommended that during reassembly of push pull rods, a jointing compound be used to help protect the rivets in the joint from future corrosion.

Compliance: 1. Within 100 hours time in service after 30 April 1974 and thereafter at intervals not exceeding 1 year.

2. Within 100 hours time in service after 5 November 2003 and thereafter at intervals not exceeding 1 year.

3. If any rivets are found damaged or corroded.

This Amendment becomes effective on 20 January 2005.