Ad/Jetstream/101 - Down Lock Assembly (Cth)

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.001(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.

British Aerospace BAe 3100 (Jetstream) Series Aeroplanes

AD/JETSTREAM/101 Down Lock Assembly 11/2005

Applicability:

Model Jetstream HP137 Mark 1 and Jetstream Series 200, 3100 and 3200 aeroplanes.

Requirement:

1.    Remove from service and replace with a new or serviceable part any incorrectly heat treated radius rod down lock piston listed in Paragraph 1A of BAE SYSTEMS Service Bulletin 32-JA040547 Original Issue or later EASA approved revision.  Replace defective components in accordance with Paragraph 1 N of BAE SYSTEMS Service Bulletin 32-JA040547 Original Issue or later EASA revision.

2.    Do not install a radius rod assembly on an aircraft that contains a down lock piston identified in Paragraph 1A of BAE SYSTEMS Service Bulletin
32-JA040547 Original Issue or later EASA approved revision.

Note:  UK CAA AD G-2005-0024, EASA reference No 2005-6188 dated 22 August 2005 refers.

Compliance:

1.    At the next main landing gear radius rod overhaul but no later than 31 August 2010.

2.    From the effective date of this Directive.

This Airworthiness Directive becomes effective on 27 October 2005.

Background:

A batch of main landing gear (MLG) downlock pistons with incorrect heat treatment have been installed into MLG radius rods fitted to the above aircraft types during overhaul.  The effect of the incorrect heat treatment is reduced strength and hardness, which can lead to failure of the piston and/or contamination of the hydraulic system.  Failure of the downlock piston in combination with a loss of hydraulic pressure could result in the collapse of the affected MLG, which during the critical phases of take-off and landing will result in a loss of directional control.

James Coyne
Delegate of the Civil Aviation Safety Authority

15 September 2005