The aircraft, which was operated by a flight training school based at a grass airfield, was being manoeuvred into wind prior to pre takeoff power checks when the nose landing gear wheel separated from the nose leg. The engineering examination revealed that a fatigue failure had occurred in the nose wheel swivel/castoring pivot. The fatigue initiation was due to the material being below the minimum specified strength which had been caused by a failure in the nose landing gear manufacturing process that had not been identified by post manufacturing quality checks. The aircraft operator found cracks in a similar area on another of their aircraft of the same type and similar age and usage. The aircraft manufacturer has issued a Mandatory Service Bulletin which the Airworthiness Authority has enforced by issuing an Airworthiness Directive requiring inspection for cracking of the nose wheel swivel/castoring pivot. For the long term the aircraft manufacturer is exploring the possibility of strengthening the area of the nose wheel swivel/castoring pivot and simplify the manufacturing process.
DA40D, G-CCLB 06-06.pdf (1,561.45 kb)