On 8 May 2008, the pilot of an American Champion Aircraft (ACA) 'Citabria', model 7GCBC (registered VH-MWY), was returning to Camden Aerodrome, NSW, after a local area flight, when the upper elevator control cable fractured. The pilot was able to maintain control of the aircraft's pitch attitude using wing flaps, and subsequently landed the aircraft safely, with only minor damage to the propeller.
Laboratory examination of the failed cable found the failure (and an adjacent area of significant damage) to have developed from the progressive fatigue cracking of individual cable wires in locations where the cable passed over guide sheaves. The examination also determined that the cable had not been manufactured to conform with the requirements of the accepted standard for aircraft control cables (MIL-DTL-83420).
From 2005, the aircraft manufacturer changed its internal procedures to require that only cable manufactured and certified to MIL-DTL-83420 be used for new aircraft production. Following the cable failure, the Civil Aviation Safety Authority (CASA) published an Airworthiness Bulletin (AWB), highlighting the issues associated with the use of non-MIL standard cables in aircraft control applications, and recommended that owners and maintainers of American Champion Aircraft ensure that periodic inspections are conducted with appropriate veracity.
|Date:||08 May 2008||Investigation status:||Completed|
|Time:||1716 EST||Investigation level:||Complex - click for an explanation of investigation levels|
|Location:||Camden Aerodrome NSW W/19 km|
|State:||New South Wales||Occurrence type:||Flight control systems|
|Release date:||24 June 2009||Occurrence category:||Serious Incident|
|Report status:||Final||Highest injury level:||None|
|Aircraft manufacturer||American Champion Aircraft Corp|
|Type of operation||Private|
|Damage to aircraft||Nil|
|Departure point||Camden, NSW|
|Departure time||1630 EST|