B757-200
Flight Crew Air Transport Pilot (ATP)
Distraction; Time Pressure; Troubleshooting; Workload
Aircraft Equipment Problem Critical
Air Traffic Control Provided Assistance; Air Traffic Control Issued New Clearance; Aircraft Equipment Problem Dissipated; Flight Crew Overcame Equipment Problem; Flight Crew Requested ATC Assistance / Clarification
Aircraft
30 minutes into cruise flight at FL400; EICAS message L Bleed Off. QRH consulted and complied with. Pressurization held cabin altitude; flight continued. Approximately 30 min later; EICAS message R Bleed off. Immediately donned O2 mask; advised ATC of descent needed for pressurization problem and complied with QRH while descending to 10;000. Reset bleed valves and they responded and regained pressurization control. Cabin altitude stabilized. We leveled at 15;000. Everything then stabilized; pressurization; and L and R Bleeds. At this point we were within 100 miles to STAR for destination airport. Elected to continue to destination airport. No further malfunctions concerning these systems occurred.
We were cruising at FL400 for about 30 minutes when we received a left bleed off EICAS message. We complied with the QRH checklist and continued the flight. About 30 minutes later we received a right bleed off EICAS message and immediately donned our oxygen masks and began a descent from FL400 and asked for a descent to 10;000 feet in anticipation of losing our pressurization. We then ran the right bleed off light QRH checklist. After we began the descent we eventually received a cabin altitude warning and compiled with that QRH checklist and were well into our descent. The Captain than decided to use his emergency authority and we attempted to reset the both bleed valves and packs which we were able to successfully accomplish and decided to level off at 15;0000 feet and then climbed back to FL200 in order to avoid some weather. After being able to restore both packs and bleed valves and normalize pressure; we decided to continue to our destination as none of the checklists required us to land at the nearest suitable airport and we were also able to reestablish normal bleed valve; pack and pressurization. After this point the remainder of the flight and landing were uneventful.
A Boeing 757 flight crew reported a failure of both engine bleed air valves resulting in a gradual loss of cabin pressurization. After troubleshooting the problem they were able to restore the engine bleed system to normal operation and regain cabin pressurization. They proceeded to the destination airport and landed uneventfully.