What happened
On August 6, 2018, an A321-231, registration PT-MXA, operated by TAM Linhas Aéreas S/A, was performing a scheduled passenger flight from Brasília to Fortaleza. During the descent phase, the aircraft's speed exceeded the selected target of 340 knots as it passed through 14,800 feet.
In an attempt to correct the speed, both the pilot flying and the pilot monitoring simultaneously applied inputs to the aircraft's sidesticks. This concurrent action resulted in a positive load factor of approximately 1.6g. The sudden movement caused a flight attendant, who was standing in the galley, to lose her balance and fall. The crew member suffered a severe fracture to her left ankle and distal tibia.
The investigation
CENIPA investigators examined the flight data recorder (FDR) and cockpit voice recorder (CVR) to reconstruct the sequence of events. The investigation focused on the flight crew's interaction with the flight controls and their communication during the speed excursion. The investigation also reviewed the aircraft's maintenance status, noting that certain items, including a partial speed brake malfunction, were being operated under the Minimum Equipment List (MEL).
Findings
- Simultaneous sidestick inputs: The primary cause of the increased g-load was the simultaneous use of both sidesticks by the crew members.
- Communication failure: There was a lack of verbal coordination between the pilots; the pilot monitoring did not announce "I have control," and neither pilot communicated their intention to adjust the speed via the sidesticks.
- Procedural non-compliance: The crew failed to adhere to the Flight Crew Techniques Manual (FCTM) guidelines, which specify that only one pilot should act on the controls at a time.
- Training gaps: The investigation noted that a lack of specific training regarding techniques for handing over or assuming aircraft control may have contributed to the error.
- Crew coordination: The coordination between the pilots was compromised by the inappropriate alternation of control functions without proper notification.