The two JRA-776-1 fuselage lateral tie rods fitted to de Havilland DH82A Tiger Moth, registered VH-TSG, had significant, pre-existing fatigue cracks in the threaded sections. The parts’ service life was significantly less than the published retirement life for DH82A tie rods of 2,000 flight hours or 18 years).
The safety action by the UK CAA, which was automatically mandated by CASA and CAANZ, minimises the safety risk associated with this safety issue.
Since the release of safety issue AO‑2013‑226‑SI-01, the ATSB has, as a result of its investigation, a clearer understanding of the development, manufacture, installation and use of the JRA-776-1 fuselage lateral tie rods. This has resulted in the identification of a number of additional safety issues that present a risk to the operation of all DH82 or DH82A Tiger Moth aircraft fitted with these tie rods. Safety actions taken to address the identified risks follow (see safety issues AO-2013-226-SI-04, AO-2013-226-SI-05, AO-2013-226-SI-07 and AO-2013-226-SI-02).
In response to this safety issue the UK CAA issued an Emergency Airworthiness Directive (AD) number G-2014-0001-E on 21 March 2014. That AD mandated that DH82 aircraft be restricted to non-aerobatic flight until the place of origin of the fuselage lateral tie rods was checked. A compliance time of 10 flight hours was given in order to check compliance with the AD. If the tie rods were identified to be a JRA‑776-1 product or their manufacturer could not be ascertained, then the tie rods had to be replaced. CASA and CAANZ automatically mandated the UK CAA emergency AD on the date of its issue.
Although CASA and other organisations are considering additional requirements in respect of the fuselage lateral tie rods in Tiger Moth aircraft, the ATSB is issuing the following safety advisory notice to ensure that all operators and owners of Tiger Moth aircraft are aware of the safety issue as soon as possible.
The Australian Transport Safety Bureau advises all owners and operators of de Havilland DH82 and DH82A (Tiger Moth) aircraft to consider the safety implications of the initial findings of this investigation regarding the fatigue cracking on both lateral tie rods and take action where considered appropriate. The safety issue has particular relevance to aircraft fitted with JRA-776-1 tie rods, aircraft that have been used for aerobatics, aircraft that have experienced heavy landings, and/or aircraft with lateral tie rods that have accrued longer periods in service.
