What happened
On 28 January 2019, a DHC-8-402 Dash 8, registration G-FLBC, was performing a scheduled passenger flight from East Midlands Airport to Edinburgh Airport. During the climb, while passing approximately FL150, the crew experienced a sudden and rapid increase in cabin altitude, which was accompanied by noticeable physical sensations of changing air pressure. Shortly after these sensations, the cabin altitude warning activated.
In response to the depressurisation, the flight crew donned oxygen masks and initiated an emergency descent. The crew issued a MAYDAY call to Air Traffic Control. Following the descent, the crew followed standard operating procedures to inform the cabin crew, and a discussion was held regarding the welfare of the passengers and crew. The cabin crew delivered a passenger announcement using an emergency aide memoire.
After performing the 'Rapid Depressurisation or Emergency Descent' checklist, the pilots attempted the 'Manual Pressurisation' checklist. When manual control of the pressurisation proved impossible, they transitioned to the 'Unpressurised Flight' checklist. Given the available fuel and favorable weather, the commander decided to proceed to the destination. The MAYDAY call was downgraded to a PAN-PAN, and the aircraft landed at Edinburgh Airport without further incident. The airport fire service met the aircraft, and the passengers disembarked safely with no injuries reported.
The investigation
The investigation focused on the cause of the sudden loss of cabin pressure. It was noted that the aircraft had experienced a minor pressurisation issue during its previous flight sector, and the crew had been in contact with maintenance control regarding this matter prior to the flight. Subsequent inspections of the aircraft revealed a hole in the lower lip of the rear baggage door seal.
Findings
- The aircraft experienced a cabin depressurisation during the climb phase.
- The primary cause was a hole in the rear baggage door seal.
- The aircraft had a known, minor pressurisation issue on the preceding flight sector.