Cat. 3 investigation report: report concerning an occurrence with limited consequences, based on one or more statements not independently validated by the BEA.
This is a courtesy translation by the BEA of the Final Report on the Safety Investigation published in June 2021. As accurate as the translation may be, the original text in French is the work of reference.
Note: The following information is principally based on the statement made by the pilot. This information has not been independently validated by the BEA.
1 - HISTORY OF THE FLIGHT
The pilot took off from Biarritz aerodrome bound for Toulouse-Lasbordes aerodrome in the scope of his professional activity. During the approach to runway 15, the pilot noticed that the down light of the left main landing gear was off. He announced to the controller that he was aborting the approach in order to deal with the failure during the aerodrome circuit. He added that he carried out four or five landing gear cycles while performing pull-ups but saw that the left light remained off. The pilot specified that during the second approach, the aural warning was not sounding. He asked the controller to confirm that the landing gear was extended, voluntarily omitting to specify which one was posing a problem in order not to influence her answer. During the base leg and then on final, the controller checked with binoculars and confirmed that the three landing gear seemed to be extended.
The pilot continued the precautionary landing at the indicated airspeed of 65 kt with flaps fully extended. The aeroplane touched down on the main landing gear, within the first third of the runway. During the landing run, the left gear strut collapsed and folded under the aeroplane. The propeller then the left wing made contact with the runway. The aeroplane’s path deviated to the left.
The aeroplane veered off the runway just before taxiway B, crossed the latter and came to rest on the shoulder, about 30 metres from the edge of the runway.
2 - ADDITIONAL INFORMATION
2.1 Site information
Around 50 cut marks made by the left propeller were visible on the left side of the runway.
Left and right tire marks were also visible, indicating a hard braking action between taxiways C and B.
2.2 Aeroplane information
The left flap and left aileron were damaged. The three blades of the left propeller were bent backwards, showing that the propeller was not delivering thrust.
The maintenance workshop manager noted that the rivets on the torque tube rear support of the left main landing gear were sheared.
An inappropriate adjustment of the torque tube tension could have caused this failure. The torque tube’s function is to operate the landing gear. Its failure leads to a loss of the locking function of the landing gear concerned, whether during a normal extension or emergency extension.
The service bulletin MEB08-2 of 14 April 2008 issued by the FAA specified that rubbing had been observed between the torque tube and the attaching support bracket of the main gear. It specifies a mandatory inspection at the next scheduled 100 hour/12 month (annual) type inspection or 12 months, whichever occurs first.
The owner indicated that the aeroplane had flown 53 hours since its last inspection.