What happened
On 4 September 2001, a Cessna 404 Titan, registration G-BWLF, was returning to Farnborough Airport following an aerial survey mission. The pilot performed a crab approach to Runway 25, utilizing the wind conditions of 30/15 kt. While the initial touchdown and ground roll appeared routine, the aircraft began to judder and the nose dropped approximately two to three seconds after the nosewheel made contact with the runway. This movement continued until both propellers struck the ground, indicating a total collapse of the nose landing gear. The pilot successfully maintained the aircraft on the runway centerline until it came to a halt. There were no fatalities and no injuries to the crew or the two passengers on board.
The investigation
Investigators examined the wreckage and found that the right-hand nose landing gear pivot trunnion lug had fractured, causing the gear leg to break rearwards and to the left. A metallurgical analysis determined that the failure was caused by bending overload, likely triggered by excessive side loads. Although a small low-cycle fatigue crack was discovered on the fracture face, it was deemed too shallow to have significantly weakened the component.
Further review of the aircraft's maintenance history revealed that the required inspections mandated by Cessna Service Bulletin MEB88-5 Revision 2 had been performed roughly seven months and 57 flying hours prior to the incident. This bulletin required periodic eddy current and dye-penetrant inspections of the trunnion lugs to check for cracks.
Findings
- The nose landing gear collapsed because the right-hand pivot trunnion lug failed due to bending overload.
- The failure was likely exacerbated by excessive side loads during the landing sequence.
- A small fatigue crack was present in the lug, though it was not large enough to be the primary cause of the structural failure.
- The existing inspection protocols could not provide a guarantee of detecting cracks of this specific depth.