What happened
On 19 September 2020, a Piaggio P 180 Avanti II, registration D-IPPY, was conducting a commercial passenger flight from London Luton Airport to Riviera Airport, Italy. While climbing through FL220, the pilot in command heard an unusual dull noise, which was suspected to be the aircraft's outflow valve opening.
Following this sound, the cabin altitude began to rise rapidly at a rate of approximately 4,000 ft/min. The crew notified Air Traffic Control of their intention to level off at FL230 to monitor the situation. However, as the cabin altitude continued to climb and approached 10,000 ft, the commander manually deployed the passenger oxygen masks, and the crew donned their own masks.
A PAN was declared, and the aircraft was cleared for an emergency descent to FL100. After completing the necessary checklists, the flight diverted to London Biggin Hill Airport. The aircraft landed safely with no injuries to the two crew members or three passengers, and no damage was sustained by the aircraft.
The investigation
The AAIB investigation focused on the cause of the depressurization. Engineering inspections of the aircraft's systems were conducted to identify the source of the pressure loss. The investigation established that a clamp used to connect a hose within the Environmental Control System had become loose. It was determined that this loosening may have been caused by vibration.
Findings
- The primary cause of the loss of cabin pressure was a loose clamp connecting a hose to the Environmental Control System.
- Vibration was a suspected contributing factor in the loosening of the component.