FRANKFURT and LONDON—The crash of anAirbus A400M airlifter that killed four people on May 9 may have been caused by new software that cut off the engine-fuel supply, industry sources have said.
Four company personnel, including both test pilots, died when the aircraft—which had been destined for the Turkish air force—crashed on agricultural land north of Seville San Pablo Airport shortly after takeoff on its first flight.
Two flight-test engineers were pulled from the wreckage and remain in the hospital.
Sources have told Aviation Week that aircraft MSN23, destined for Turkey, featured new software that would trim the fuel tanks, allowing the aircraft to fly certain military maneuvers.
The sources state that the exact sequence of events is not yet clear, nor is it clear whether all four engines failed at some point. Some reports have suggested three engines failed. There also seems to have been a trimming issue leading to strong banking that was not recoverable.
The fuel supply was re-established, but not quickly enough for recovery to safe flight.
Details about the software have emerged as Airbus Defense and Space requested all operators of its A400M airlifter conduct checks on electronic control units (ECUs) fitted to the TP400 turboprop engines on the aircraft.
Airbus alerted the five air arms operating the transport aircraft to perform one-time specific checks of the ECUs on each of the aircraft’s engines before the next flight. The company also has introduced additional detailed checks, to be carried out in the event of subsequent engine or ECU replacement.
The company said these checks were necessary to “avoid potential risks in any future flights,” and adds that the results have been shared with the official investigation team.
In a statement, the company said the alert had resulted from its internal analysis and was issued as “part of the continued airworthiness activities, independently from the ongoing official investigation [into the accident].”
Airbus restarted development flight-testing of the A400M on May 12, but the company still is subject to the withdrawal of the Spanish defense ministry’s permit to test-fly production aircraft.
The majority of A400M customers have halted flights with the aircraft until more details about the cause of the accident emerge. Only France, which has six aircraft, is continuing flight operations. One of the U.K.’s aircraft is reportedly stuck in New Mexico awaiting the lifting of the British defense ministry’s self-imposed flight pause.