What happened
On October 20, 2003, a Fokker F27MK600, registration PT-TVA, operated by TAVAJ Transportes Aéreos Regulares S/A, was performing a scheduled flight from Cruzeiro do Sul to Rio Branco, with a scheduled stop in Tarauacá, Acre.
Upon landing on runway 14 at Tarauacá Aerodrome, the crew applied the Ground Fine Pitch (a mechanism used for deceleration in this aircraft type). During the landing roll, the aircraft began to veer to the left of the runway centerline. The crew attempted to correct the deviation using nose wheel steering and by applying the right main gear brakes. However, the aircraft exited the left side of the runway and struck a fiber optic inspection box, which broke upon impact.
As the aircraft continued off the paved surface, it struck several wooden fence posts. The nose gear collided with a small mound, causing it to break, and the left wing subsequently struck an embankment, which brought the aircraft to a complete stop. The aircraft sustained heavy damage to the fuselage, left wing, left and nose landing gears, left engine, and pneumatic system. All 23 occupants (3 crew and 20 passengers) evacuated the aircraft without injury.
The investigation
CENIPA's investigation focused on the loss of directional control and the mechanical state of the aircraft. Investigators noted that the braking marks on the runway indicated that only the outer tire of the right main gear had locked up, suggesting a failure in the anti-skid system.
The investigation also encountered difficulties regarding the integrity of the evidence. Investigators found indications that maintenance services may have been performed on the landing gear and the Ground Fine Pitch actuator after the accident, potentially masking the true cause of the mechanical failure. Furthermore, the operator failed to provide maintenance control records that would have been essential for verifying the aircraft's service history.
Findings
- Asymmetric thrust/drag: It was deduced that only the Ground Fine Pitch mechanism on the left engine was functioning, creating an asymmetric condition that pulled the aircraft to the left.
- Maintenance deficiencies: There were strong indications of deficient maintenance, specifically regarding a potential lack of brake fluid and a failure in the system responsible for the Ground Fine Pitch actuator. The company's organizational climate was characterized by extreme demotivation due to financial instability, which led to the acceptance of operating aircraft with unsafe airworthiness conditions.
- Operational errors: The crew failed to properly execute procedures to mitigate asymmetry, such as returning the power levers to minimum and moving the HPU lever from the Feather (Ground Fine Pitch) position to Shut.
- Organizational factors: The operator was in a pre-bankruptcy state, facing significant financial difficulties, unpaid salaries, and a lack of essential spare parts.
- Infrastructure: The aerodrome lacked an Aeronautical Emergency Plan (PEAA).