Incident Overview
On May 21, 2009, at 2147 Eastern Daylight Time, an Airbus A330-200 with Brazilian registration PT-MVB, operated by TAM Airlines as Flight 8091, was in cruise flight at Flight Level 370. The aircraft was en route from Miami International Airport, Florida, to São Paulo Guarulhos International Airport, Brazil, when it experienced a loss of primary speed and altitude information.
Sequence of Events
Initial reports indicated that the flight crew noted an abrupt drop in outside air temperature and observed St. Elmo's Fire on the windshield. Shortly thereafter, the Air Data Reference System was lost, leading to disconnections of the autopilot and autothrust systems. The primary airspeed and altitude indications were also lost.
Crew Actions and System Status
The flight crew continued to operate the aircraft using backup instruments. After approximately 5 minutes, primary data was restored. However, the airplane remained in alternate flight law and displayed a rudder travel limit flag. The crew determined that they could not restore normal law and continued the flight under appropriate procedures.
Outcome
The flight landed at São Paulo Guarulhos International Airport with no further incident. There were no injuries to passengers or crew, and no damage to the aircraft.
Investigation
With the concurrence of the Brazilian Centro de Investigação e Prevenção de Acidentes Aeronáuticos (CENIPA), the National Transportation Safety Board (NTSB) initiated an incident investigation into this event. The final report for this incident was combined with and can be found under NTSB investigation number DCA09IA064.