Incident on 21 April 2018
On 21 April 2018 at 07:10 local time, during a flight from Modlin Airport (EPMO) to Zurich Airport (LSZH), a cabin decompression occurred at flight level FL400. The flight crew applied standard operating procedures as per the Aircraft Flight Manual and the operator's operational manual. They decided to abort the flight and return to Modlin. The landing was performed without exceeding aircraft limits. The details of the event and the decisions made by the crew, as well as work performed by the maintenance station, were described in the AMC Aviation final report dated 15 June 2018.
During maintenance conducted from 23 to 28 April 2018, the manufacturer Bombardier Inc. recommendations were followed. After the work, a technical flight was performed up to FL450, and the aircraft was deemed airworthy. Until the next event, the aircraft operated four flight segments, including three with a different captain not involved in the analyzed incidents.
Incident on 8 May 2018
On 8 May 2018 at 16:30 local time, during a flight from Modlin to Geneva Airport (LSGG), while descending from FL410 for landing, the crew heard a loud bang from the rear of the cabin and observed a sudden increase in differential pressure on the indicator. The flight crew donned oxygen masks and performed the QRH procedures for cabin decompression. They continued the flight at FL200, and at the direction of the Rhein Radar air traffic control, set the transponder to squawk 7700. The crew continued to Geneva while wearing oxygen masks, where a safe landing was made. The operator, CAMO department, and maintenance stations were notified. Details of the event, crew decisions, and technical work performed were described in the AMC Aviation final report dated 15 June 2018.
Cause
The cause of the incidents was a vacuum line failure, consisting of a lack of tightness in the pressurization system.
Maintenance and Preventive Actions
The user performed a re‑execution of Service Bulletin SB 60-21-16 revision 2 dated 5 June 2017. The Polish State Commission on Aircraft Accident Investigation (PKBWL) did not issue any safety recommendations.