History of the Flight
Air Transat Flight 961, an Airbus A310-308, departed Varadero, Cuba, for Québec, Quebec, at 0645 UTC with 9 crew and 262 passengers. At 0702 UTC, while level at flight level (FL) 350 about 90 nautical miles south of Miami, Florida, the flight crew heard a loud bang followed by several seconds of vibration. The aircraft entered a Dutch roll, and the captain disconnected the autopilot to manually fly the aircraft. During the Dutch roll, the aircraft climbed to approximately FL 359. The crew initiated a descent and informed air traffic control of an autopilot problem. The Dutch roll lessened during the descent and ceased when the aircraft passed FL 280. No emergency was declared. The crew initially planned to divert to Fort Lauderdale but after consulting with company dispatch elected to return to Varadero. The aircraft landed on Runway 06 at Varadero at 0819 UTC. During the landing flare, rudder inputs were ineffective for correcting a slight crab, and nose wheel steering was used for directional control. After shutdown, a visual inspection revealed that the rudder had broken off and most of it was missing.
Injuries and Damage
One flight attendant suffered a minor back injury during the event. All other 9 crew and 262 passengers had no injuries. The aircraft sustained substantial damage to the rudder, delamination of the rear attachment fittings of the vertical tail plane, and minor damage to the tail cone.
Investigation Findings
The investigation found no flight control system anomalies or conditions that could have led to the rudder breakup. The nature of the structural damage could not be precisely identified during flight; only during the landing flare did abnormal rudder response become apparent. The crew faced "flight control difficulties of unknown origin" with no established procedure for such a situation. No ECAM messages or cockpit warnings related to the control problem occurred. The aircraft was equipped and operated in accordance with applicable regulations, and weather and navigation aids were not factors. Maintenance procedures and the aircraft's maintenance program were found without shortcomings.
Crew Actions
The crew had only encountered a Dutch roll in simulator training. There was no procedure for Dutch roll in the Quick Reference Handbook or on ECAM; the Airplane Upset Recovery Training Aid provides general guidelines but does not specifically address systems like autopilot. The crew cycled through ECAM pages to diagnose the problem but received no relevant messages. They knew descending might lessen the Dutch roll, which it did. The decision to return to Varadero was based on the absence of remaining symptoms, no cockpit indications, the aircraft's ability to continue normally at low altitude, and the company's better capability to handle the aircraft and passengers at Varadero.
Communication and Decision Making
Information about the severity of events in the aft cabin—such as the magnitude of forces and the noise—was not communicated to the flight crew. Cabin crew assumed their experience was representative, and the captain assumed the flight director would relay relevant information. Air Transat's written procedures do not require the flight director to seek information from the cabin crew. The lack of information sharing may not have affected the outcome in this occurrence but could have severe consequences in other circumstances.
Maintenance
No shortcomings were found in Air Transat's maintenance organization, facilities, procedures, or personnel qualifications. The aircraft was maintained in accordance with applicable regulations.