What happened
On March 10, 2010, a Beechcraft A-36, registration PT-JXO, departed from Porto Alegre (SBPA) destined for Itaqui (SSIQ) to transport passengers. During the approach to Itaqui, the crew noticed that the landing gear down-lock indicator for the left leg failed to illuminate.
As a precautionary measure, the crew decided to divert to Santa Maria (SBSM), which offered better emergency support resources. During the diversion, the crew spent approximately one hour and 40 minutes attempting to manually extend the landing gear, but they were unsuccessful. The aircraft subsequently performed an emergency landing on runway 29 at SBSM with the landing gear in the retracted position. The pilot shut down the engine during the final approach to mitigate impact. The aircraft sustained light damage, and both crew members were uninjured.
The investigation
The investigation focused on the mechanical failure of the landing gear system. Investigators determined that the actuation cable for the upper lock of the landing gear had broken, which prevented the gear from unlocking and extending from its up position.
While the specific cause of the cable breakage could not be determined, the investigation noted that the manufacturer's maintenance protocol for this specific cable is "on condition," requiring periodic inspections of its general state and functionality. A review of the aircraft's maintenance logs showed no records of a recent replacement for the broken cable.