What happened
On June 14, 2020, China Airlines flight CI202, an Airbus A330-302 with registration B-18302, arrived at Taipei Songshan Airport from Shanghai Pudong International Airport. The flight was carrying 87 passengers and 11 crew members. During the landing roll on runway 10, the aircraft experienced a simultaneous failure of all three flight control primary computers (FCPC/PRIM).
As the aircraft touched down, the loss of these computers immediately disabled the ground spoilers, thrust reversers, and the autobrake system. The flight crew, recognizing that the deceleration devices had failed to activate, responded by applying rapid, full manual braking. Despite the loss of automated systems and the presence of a light tailwind and wet runway conditions, the crew managed to bring the aircraft to a complete stop approximately 3/0 feet before the end of the runway. There were no injuries and no damage to the aircraft.
The investigation
The Taiwan Transportation Safety Board (TTSB) conducted an investigation involving international partners, including the French BEA and Airbus. The investigation examined the aircraft's flight data recorder (FDR), technical logbooks, and the flight control software logic. Investigators analyzed the transition from flight to ground laws and the specific behavior of the rudder order monitoring during the touchdown phase.
Findings
- The primary cause of the incident was the simultaneous failure of all three flight control primary computers (FCPCs) due to an undue triggering of the rudder order COM/MON monitoring.
- At the moment of touchdown, as the aircraft transitioned from lateral flight law to lateral ground law, a high level of asynchronism between the COM and MON channels, combined with pilot pedal inputs, caused the rudder order difference to exceed the monitoring threshold.
- The failure of FCPC1 triggered a cascading effect, where the subsequent handover of control to FCPC2 and FCPC3 also failed due to high asynchronism at that moment.
- The loss of the FCPCs directly resulted in the loss of the thrust reversers, ground spoilers, and the autobrake system.
- The flight crew demonstrated high situational awareness and followed standard operating procedures, effectively using manual braking to prevent a runway excursion.
Safety action
Following the investigation, Airbus implemented several safety measures, including a software enhancement for the A330 family to improve the robustness of the FCPC COM/MON rudder order monitoring and reduce asynchronism during flight/ground transitions. The Taiwan CAA also issued an aviation safety bulletin advising operators to consider potential deceleration deficiencies when landing on wet runways with A330 aircraft.