What happened
During a scheduled mail and cargo flight operating between Lisbon, Ponta Delgada, and Lajes, an aircraft was performing its final leg from Lajes back to Lisbon. The plane was carrying 1,693.5 kg of mail and freight at the time of the accident.
As the aircraft began its initial climb after departing from runway 33, the number three engine experienced a failure, causing the propeller to autofeather. Within six seconds of this first failure, the number four engine also ceased operation. Following the loss of both engines, the aircraft became uncontrollable and struck hilly terrain in the vicinity of the airport. The impact resulted in the total destruction of the four-engine aircraft and caused seven fatalities, with no survivors among the occupants.
Findings
Investigations into the accident identified several contributing factors related to engine operation and aircraft configuration:
- An error in the selection of the fuel system led to the stoppage of both the number three and number four engines during the takeoff phase.
- The crew's attempt to transfer fuel from the lower tanks to the wing tanks resulted in an interrupted checklist sequence, which likely contributed to the improper fuel system setting.
- Improperly secured cargo may have negatively impacted the stability and controllability of the aircraft during the flight.
- The inability to successfully retract the landing gear in a timely manner reduced the overall performance of the aircraft during the critical climb phase.