What happened
On 2 March 2009, a Boeing 757-236, registration G-LSAA, was operating at flight level 390, approximately 30 nautical miles north-east of Athens, Greece. Following the completion of the flight and after the aircraft had landed and parked at its designated stand, the crew encountered an issue regarding the cabin doors. The doors could not be opened because the internal and external cabin pressures had not yet equalised.
The investigation
Following the occurrence, the AAIB conducted an investigation based on the accident report form submitted by the commander and subsequent enquiries. The investigation focused on the state of the aircraft's pressurisation system upon arrival. It was established that the outflow valve had remained in a position that prevented the necessary pressure balance. To resolve the situation, the crew had to manually open the outflow valve. Even after this manual intervention, the process of equalising the pressure between the cabin and the exterior environment took a significant amount of time before the doors could be safely operated.