What happened
A First Air Boeing 727-225, registration C-FIFA, was performing a scheduled cargo flight from Corcaigh International Airport, Ireland, to East Midland Airport, England. During the takeoff roll, the aircraft's aft cargo door began to open. As the plane climbed through 400 feet and the landing gear was being retracted, the second officer noticed the aft cargo door light illuminated on the annunciator panel.
Shortly after the gear retraction and during flap retraction, the number 3 engine experienced a series of compressor stalls. The captain responded by reducing the thrust lever to idle, leveling the aircraft, and initiating an immediate return to Corcaigh Airport. The aircraft landed safely without injuries, though the engine experienced minor damage. Upon inspection, emergency crews found the aft cargo door partially open with a bent hinge mechanism. Additionally, several cargo parcels were found scattered on the runway and the adjacent grass area.
The investigation
The investigation focused on why the door was not secured and why the cockpit warning system failed to alert the crew. Investigators examined the ground handling procedures at Corcaigh, where responsibilities for securing doors were split between DHL Aviation and Servisair Ltd. It was noted that while Servisair was contractually responsible for securing doors, local practices allowed DHL personnel to load the aft section independently.
Technical analysis of the aircraft revealed that the door was likely left in a position where it was not fully latched, but appeared closed to the loading crew. The investigation also looked into the functionality of the door microswitch. Although the switch was discarded during repairs and could not be tested, the investigation considered the possibility of intermittent electrical malfunctions caused by vibration or contamination.
Findings
- The aft cargo door was likely not properly closed and secured prior to engine start and departure.
- The aft cargo door microswitch likely malfunctioned, providing the flight crew with a false indication that the door was securely locked.
- The division of responsibilities between the two ground handling agencies created a risk of miscommunication regarding the final securing of the cargo door.
- Airflow disruption caused by the partially open door near the engine intake likely induced the compressor stalls during flap retraction.