What happened
On June 18, 2009, an Embraer EMB-820C, registration PT-RAS, operated by the Corpo de Bombeiros Militar do DF, was performing a post-maintenance test flight at the Anápolis Aerodrome (SWNS) in Anápolis, Goiás. The flight, which included two crew members, was intended for training and testing following a 1,000-hour inspection.
After successfully completing two touch-and-go maneuvers, the aircraft began its third attempt. Approximately 500 meters into the maneuver, the left main landing gear unexpectedly retracted. This caused the aircraft to veer to the left side of the runway, leading to the left propeller striking the ground. The aircraft sustained substantial damage, though both crew members escaped the incident without injury.
The investigation
CENIPA investigators examined the aircraft's maintenance history and the landing gear system. The investigation revealed that the aircraft had undergone a 1,000-hour inspection at an authorized workshop on June 1, 2009. During the investigation, the aircraft was placed on jacks to test the landing gear cycles. Investigators were unable to achieve a successful lock in the down position; the left gear remained unlocked, even though the cockpit indicator displayed a green light, signaling that the gear was locked.
The investigation focused on the maintenance of the landing gear locking mechanism. The aircraft manufacturer's Service Manual included a note suggesting the use of a special tool (a jig) to verify the correct position of the landing gear when locked. However, the maintenance facility did not possess this tool and did not use it during the recent 1,000-hour inspection.
Findings
- The left main landing gear retracted during the third touch-and-go maneuver.
- The maintenance workshop did not use the special jig suggested by the manufacturer to certify the correct position of the landing gear lock during the 1,000-hour inspection.
- The lack of the specialized tool prevented the accurate adjustment and verification of the gear's locking mechanism.
- The maintenance of the aircraft was a contributing factor to the accident.