What happened
On October 10, 2008, an EMB-110 P1, registration PT-TAW, operated by WEISS Táxi Aéreo Ltda., was performing a ferry flight from Campinas (SBKP) to Bacacheri (SBBI) in Curitiba. The flight was being conducted under Instrument Flight Rules (IFR) due to low ceilings at the destination.
Upon landing on runway 36, the aircraft touched down in the first third of the runway. During the landing roll, the aircraft experienced a sudden and severe yaw to the right. The crew was unable to maintain directional control, causing the aircraft to exit the right side of the runway and come to rest in a grassy area. The aircraft sustained substantial damage to its landing gear, wings, propellers, and engines, as well as damage to runway lighting and signage. The two pilots on board were uninjured.
The investigation
CENIPA investigators examined the aircraft's engines and mechanical components. The investigation focused on the operation of the reverse thrust systems. Technical analysis of the left engine revealed that the reverse thrust control teleflex cable had become detached from its mounting screw. Furthermore, the investigation found that the right engine's starter generator was loosely installed, with the retaining strap only secured to the engine flange.
Investigators also reviewed the flight crew's experience and decision-making. While both pilots were qualified, the co-pilot, who was acting as the pilot flying, had no prior experience operating this specific model equipped with reverse thrust. The investigation also noted that the commander, rather than taking control to correct the yaw, instructed the co-pilot to continue using maximum reverse thrust.
Findings
- Improper maintenance of the left engine's reverse thrust mechanism, specifically the detachment of the teleflex cable, created an asymmetric thrust condition.
- The application of reverse thrust caused a strong rightward yaw because the left engine accelerated without the corresponding change in propeller pitch.
- The flight crew's judgment regarding the use of asymmetric reverse thrust was a contributing factor, as the commander did not intervene to stop the use of reverse thrust once directional control was lost.
- The co-pilot's lack of experience with reverse thrust operations on this specific aircraft model contributed to the difficulty in managing the sudden asymmetric forces.
- The aircraft's touchdown point was significantly forward of the normal touchdown zone, necessitating the use of reverse thrust.