Incident Overview
On March 5, 2013, at approximately 20:30 local time, an Airlinair ATR 72-212 registered F-GVZL experienced a mechanical failure during landing rollout at Toulouse-Blagnac Airport. The aircraft was operating flight A5 703 from Marseille-Provence with 31 passengers and four crew members on board.
Sequence of Events
During the rollout on runway 14 Left, the crew heard a noise followed by vibrations originating from the nose gear. As the aircraft reached the end of the runway and prepared to turn left onto an exit taxiway, the captain discovered that nose wheel steering control had been lost. The pilot applied brakes, and after another noise was heard at the front, the aircraft came to a stop on the runway centerline.
Technical Findings
Investigation revealed that the two half-compasses of the nose landing gear had separated due to the loss of the connecting shaft. Both tires were dislodged from their rims, and the proximity switch housing was detached, hanging by its wiring harness. The missing shaft, a washer, and a support bracket were found approximately 1,000 meters past the runway threshold.
Metallographic examinations indicated advanced corrosion on the threaded section of the shaft and damage to the threads consistent with the loss of the locking nut or assembly components. The anti-corrosion treatments (paint and cadmium plating) were absent on the threaded area. The last major maintenance on this component occurred in April 2012, when the shock absorber was replaced; at that time, no corrosion was noted, and the shaft was not replaced.
Safety Actions
Following the incident, ATR issued operational messages recommending thorough inspections of nose gear compass shafts. The manufacturer also revised maintenance work cards to include mandatory replacement of washers and inspection for corrosion. Messier-Dowty-Bugatti issued a Service Bulletin in September 2014 requiring detailed examination of the assembly and replacement of corroded shafts.