What happened
On June 5, 2007, an MD-83, registration OE-LMM, operated by MAP, experienced a significant flight excursion during takeoff from Lanzarote Airport. The flight, a non-scheduled passenger service carrying 140 passengers, followed an initial leg from Madrid-Barajas.
During the takeoff roll at Lanzarote, the aircraft was in an unapproved configuration with the slats retracted and flaps at 0 degrees. Following rotation at approximately 145 knots, the stick shaker activated, and the aircraft entered severe rolling oscillations, swinging as far as 63 degrees to the right and 60 degrees to the left. The crew managed to regain control and climbed to 5,000 feet before deciding to return to the airport. The aircraft landed safely without further incident, and there were no injuries and no damage to the aircraft or third parties.
The investigation
The investigation established that the aircraft's systems were operating in "flight mode" while on the ground. This occurred because a maintenance task performed the previous night involved checking strobe lights, which required opening the left ground control relay circuit breaker. Maintenance personnel failed to reset this circuit breaker, causing the aircraft to incorrectly signal that it was already in flight.
Because the aircraft was in flight mode, the Takeoff Warning System (TOWS) failed to alert the crew that the flaps and slats were not properly configured for takeoff. Furthermore, the investigation found that the crew had ignored various cockpit warnings, including stall indicators and flight director faults, during both the Madrid and Lanzarote flight legs. The investigation also identified discrepancies in the operator's training records and a lack of adherence to standard operating procedures by both the maintenance and flight crews.