Aviation safety issues and actions

Unknown fatigue life of alternative tie rod design

Issue number: AO-2013-226-SI-04
Who it affects: Owners and operators of DH82 and DH82A Tiger Moth aircraft fitted with JRA 776 1 fuselage lateral tie rods
Issue owner: Civil Aviation Safety Authority
Transport function: Aviation: General aviation
Background: Investigation Report AO-2013-226
Issue release date: 21 January 2016
Current issue status: Adequately addressed
Issue status justification:

As a result of the safety action taken by the United Kingdom Civil Aviation Authority, New Zealand Civil Aviation Authority and the Civil Aviation Safety Authority in response to safety issue AO‑2013‑226‑SI‑01, all JRA-776-1 tie rods were removed from service. This action minimises the safety risk associated with this safety issue.

Safety issue description

When approving the change in material for the manufacture of the replacement tie rods, the design engineer did not identify that the original parts had a life limitation, or that they had shown susceptibility to fatigue cracking. As a result, the engineer did not compare the fatigue performance of the alternative design to the original, and the replacement tie rods were manufactured to that design and released into service with an unknown fatigue life.

Last update 24 February 2016