What happened
On June 6, 2012, a Hawker Beechcraft C90GT, registration PR-CMF, was performing a local systems verification flight following maintenance at Santa Genoveva Aerodrome (SBGO) in Goiânia, Brazil. The crew consisted of a pilot and two mechanics.
During the approach for runway 14, the pilot noticed that the left main landing gear had failed to extend completely. Although an audible warning alarm triggered as power was reduced, the crew did not declare an emergency to air traffic control. The crew attempted to extend the gear using the normal system and subsequently attempted a manual extension; however, they failed to follow the full checklist procedure, specifically neglecting to pull the circuit breaker as required by the manual for emergency extension.
Upon landing, the crew opted for a longer landing roll without using reverse thrust. Approximately 1,100 meters into the rollout, the left main landing gear retracted. This caused the pilot to lose directional control, leading the aircraft to exit the runway and come to a stop five meters from the left edge of the pavement. The aircraft sustained light damage, and all 3 occupants were uninjured.
The investigation
CENIPA's investigation focused on the mechanical failure and the crew's response. Analysis of the Cockpit Voice Recorder (CVR) revealed that the crew relied on personal experience and knowledge rather than following the prescribed abnormal procedures checklist. Furthermore, the investigation found that the crew did not declare an emergency despite the latent danger posed by the gear malfunction.
Mechanical examination of the hydraulic pump revealed worn washers, deformed connections, and excessive corrosion on a solenoid. While the left main landing gear actuator cylinder was removed for testing, it was later reported lost by the maintenance provider, preventing a full functional verification of that specific component.
Findings
- The left main landing gear failed to lock in the down position during approach.
- The crew did not execute the manual landing gear extension procedure in its entirety, specifically regarding the circuit breaker.
- Inadequate cockpit coordination and pilot judgment contributed to the sequence of events.
- The crew failed to declare an emergency to air traffic control services.
- The left main landing gear retracted during the landing roll, causing the runway excursion.