Updated: Mar 6, 2022
A Dornier 328-100 was boarding its 16 passengers at Edinburgh Airport (Scotland) for a flight to London City Airport (England) on this day in aviation history. It would be the fourth and last sector of the day.
The passenger door after the aircraft was parked (© aaib.gov.uk)
With all passengers on board and all flight, preparations completed the passenger door was closed by a cabin attendant inside the aircraft with the assistance of a member of the groundcrew pushing the door from the outside. The door was locked by moving the internal door handle (assisted by a spring) to the locked position. Proper closure and locking of the door was confirmed by the flight crew with two separate indications;
A green indication on the DOORS system page of the MFD (Multi Function Display)
Extinguishing of the red "DOORS" caption on the CWP (Central Warning Panel), located just below the glare shield.
The engines were started and the aircraft started its taxi to the runway, while the cabin crew carried out their duties. Once these were completed the cabin crew took their seats, informing the flight crew the cabin was ready.
The co-pilot was the pilot flying for this sector and once take-off clearance was received take-off was initiated on a wet runway with a 10-knots crosswind from the right. The aircraft was accelerating down the runway when, at a speed of 100 knots (V1 was 107 knots), the red "DOORS" warning iluminated on the CWP iluminated and the noise level in the flight increased dramatically at the same moment. Th co-pilot immediately called "STOP STOP STOP" and aborted the take-off, bringing the aircraft to a full stop on the runway. It the aircraft stationary the captain shortly left the flightdeck to asses the situation while ATC was informed by the co-pilot. As the captain left the fligth deck he noticed the passenger door was partly opened. Internal door handle (© aaib.gov.uk) Upon his return to flightdeck the captain shut the left engine down and he then taxied the aircraft to a parking stand, where the passenger sdisembarked from one of the rear doors. Once the passengers had disembarked, the operator asked the commander if the crew would operate another aircraft back to London. He agreed this with the crew and they flew the same passengers to London Stansted Airport later the same evening on another aircraft.
After the incident pictures of the door and its attachments were made. Both door hinge arms were both nearly completely fractured, with only a flange on each hinge arm "holding on". It was determined that the door locking mechanism was fully serviceable and the door could be closed and locked, once it was closed the aircraft was ferried to the operators maintenance station at Cambridge (England) where the Air Accident Investigation Branch initiated its investigation in to the incident.
Cracked aft hinge arm (© aaib.gov.uk)
Besides the damaged to the doorhinges and handrails no abnormalities with the door, door mechanism or door locking mechanism were found. The Air Accident Investigation Branch conclude their report (available by clicking here) with the following probable cause:
"The most probable cause of the accident was that the senior cabin attendant grasped the inner door handle to restrain her upper body during the rapid acceleration of the aircraft. The ergonomics of the cabin crew seat and door handle made such an involuntary action readily conceivable. Such action lead to the door unlatching and opening rapidly"