Incident Overview
On September 22, 2015, at 09:56 local time, a commercial ferry flight operated by Darwin Airline SA encountered a rapid decompression event. The aircraft, an SB20 registered as HB-IZP, was en route from Geneva (LSGG) to Rome Fumicino (LIRF). At the time of the incident, the aircraft was cruising at Flight Level 270 in Italian airspace, approximately 75 kilometers west of Florence.
Crew and Operational Context
The flight crew consisted of a Swiss captain born in 1968 and a Swiss first officer born in 1976. The captain held an Airline Transport Pilot Licence (ATPL(A)) with a total of 10,992 hours, including 5,373 hours on type. The first officer held a Commercial Pilot Licence (CPL(A)) with 4,558 total hours and 2,500 hours on type. No passengers were on board during this ferry flight.
Sequence of Events
Approximately 45 minutes into the flight, the crew observed a rapid increase in cabin altitude followed by a "CAB ALT HI" warning. The pilots donned oxygen masks as the cabin altitude exceeded 14,000 feet, triggering a "PAX OXY ACTIVATED" alarm. The crew declared a MAYDAY and initiated an emergency descent to Flight Level 100 while applying the rapid decompression checklist. Upon reaching FL140, the crew removed their oxygen masks, stabilized the aircraft at FL100, cancelled the distress call, and continued to the destination.
Investigation Findings
Post-incident maintenance initially involved replacing the exhaust regulation valve and the pressurization control computer, but the issue persisted. A subsequent fuselage inspection identified that the cargo door seal had detached from its housing over a length of approximately 40 cm due to cabin overpressure. The seal was re-adhered to its original position, and the aircraft returned to service after a successful test flight.