What happened
On October 3, 2021, a Diamond DA 42 NG, registration D-GMAE, was performing a private flight from Madeira, Portugal, to Tenerife Norte/Ciudad de La Laguna Airport (GCXO), Spain. The aircraft was carrying a pilot and two passengers.
Immediately after touching down on runway 30 at approximately 17:19 local time, the pilot opened the overhead ventilation windows to regulate cabin temperature. Shortly after, the pilot felt a slight impact, which was initially assumed to be a bird strike. As the aircraft continued to taxi along the runway, the passenger door detached from the airframe and slid along the pavement.
The aircraft exited the runway via taxiway E-2 and proceeded to the general aviation parking area. It was only after the aircraft had come to a complete stop and the pilot exited the cabin that the loss of the door was discovered. The incident caused a temporary runway closure while airport services recovered the door debris from the runway surface.
The investigation
The CIAIAC examined the condition of the door, the hinges, and the aircraft's integrated cockpit systems. The investigation focused on two primary hypotheses: a mechanical failure of the locking mechanism or manual interaction with the door controls.
Technical analysis of the door and hinges revealed that the locking and safety mechanisms were fully functional and showed no signs of mechanical malfunction or prior defects. The damage to the door and the hinges was consistent with the door being opened while the aircraft was moving at high speed, leading to the door impacting the runway surface.
The investigation also reviewed the cockpit's Integrated Cockpit System (ICS) Garmin G1000. While the system correctly triggered both a visual "DOOR OPEN" alert on the Primary Flight Display and an audible alarm, the crew did not perceive these warnings. The investigation noted that all occupants were wearing headsets, which likely muffled the cockpit's internal alarms. Additionally, the pilot had recently opened the overhead windows, which likely increased wind noise and cabin airflow, further masking the event.
Findings
- The primary cause of the event was the unintentional opening of the passenger door by the passenger seated in the rear left seat.
- The passenger did not rule out interacting with the main door locking mechanism.
- The aircraft's safety and warning systems, including the visual and acoustic door alerts, were functioning correctly.
- The crew's use of headsets and the opening of ventilation windows prevented them from noticing the door's detachment during the taxi phase.
- There were no injuries to the three occupants, though the aircraft sustained significant damage to the door, hinges, and door structure.