Cessna Citation 550 flight crew reported a loud bang; followed by a loss of cabin pressurization; which resulted in a descent to an altitude where acceptable cabin pressure could be maintained.
Synopsis
Cessna Citation 550 flight crew reported a loud bang; followed by a loss of cabin pressurization; which resulted in a descent to an altitude where acceptable cabin pressure could be maintained.
Narrative
At approximately XA:40 local while in cruise at FL350; my copilot and I heard and felt a loud bang; immediately followed by indications of a cabin depressurization event. The cabin began a slow-to-rapid climb in altitude. The cabin altitude exceeded 15;000 feet before stabilizing. Passenger oxygen masks deployed as designed. We had one passenger onboard who donned his mask.The crew immediately executed the emergency pressurization memory items and commenced a descent. ATC was advised with the phraseology: 'We have a pressurization issue and we are starting a descent.'During the descent; the pressurization system was tested in various modes: left; right; and emergency pressure. The only setting that provided some stabilization was the Left Emergency Pressure Controller. Under this setting; we were able to maintain a cabin altitude of approximately 9;000 feet (noted on the cabin differential/pressurization controller gauge; left-hand side).We leveled at 10;000 feet MSL to recover; with the aircraft stabilized. ATC offered the option to continue to destination; and given that the aircraft was controllable and stable; we elected to continue eastbound at 11;000 feet to ZZZ where our maintenance provider is located.The remainder of the flight was uneventful. We landed without further incident. No injuries were sustained.
Second reporter narrative
At approximately XA:40 local; while in cruise at FL350; I was the pilot monitoring when both the Captain and I heard a sudden loud bang. Almost immediately; we noted indications of cabin depressurization; with the cabin altitude beginning to climb rapidly.The Captain called for and initiated the emergency pressurization memory items; while I communicated with ATC; advising: 'We have a pressurization issue and we are starting a descent.' ATC acknowledged and cleared us as needed.We began a descent toward 10;000 feet MSL. The cabin altitude peaked around 15;000 feet before stabilizing. Passenger oxygen masks deployed automatically as designed; and our sole passenger donned his mask without issue. Both pilots were on oxygen as required.During troubleshooting; we cycled the pressurization system through left; right; and emergency pressure controllers. Only the left-hand emergency pressure controller held the cabin stable; maintaining a cabin altitude of approximately 9;000 feet. Notably; the cabin rate-of-climb indicator responded almost exactly in parallel with the aircraft's vertical speed indicator during descent.Once stabilized at 10;000 feet; the aircraft was controllable and systems otherwise normal. After discussing options with ATC; and given our proximity to maintenance; we elected to continue eastbound at 11;000 feet to ZZZ. The remainder of the flight was uneventful; and we landed without further incident.The loud bang was sudden and disorienting; but crew coordination was effective.ATC provided descent clearance but did not issue a phone number or require further reporting. The single passenger complied with oxygen use and reported no discomfort.All applicable checklists were followed once memory items were complete.From my perspective as the First Officer; the crew responded promptly and effectively to a cabin depressurization event at altitude. The aircraft was stabilized; oxygen was used appropriately; and communication with ATC was clear. Safe continuation to destination was possible; and no injuries occurred.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.