Dispatched with the right engine bleed deferred inoperative the flight crew of a B757-200 then experienced the uncommanded closing of the left engine bleed and the associated loss of pneumatics for pressurization. While descending they started the APU and ultimately re-established pressurization from that source. They then continued to their original destination for a safe landing.
Synopsis
Dispatched with the right engine bleed deferred inoperative the flight crew of a B757-200 then experienced the uncommanded closing of the left engine bleed and the associated loss of pneumatics for pressurization. While descending they started the APU and ultimately re-established pressurization from that source. They then continued to their original destination for a safe landing.
Narrative
Shortly after reaching cruise altitude the left engine bleed switch closed itself. The right bleed was deferred inoperative. First Officer noticed pressure change in his ears. Outflow valve closed but cabin altitude was increasing. We requested lower altitude; started descent and started APU. Descending through about FL210 cabin altitude warning annunciated so we donned masks and established communications. Descending below 17;000 FT APU bleed valve opened and cabin altitude started down. Max cabin altitude was about 10;500 FT cabin masks did not deploy. Flight Attendants noticed the pressure change and early descent. Some passengers noticed the pressure change and questioned the Flight Attendants who were good about leaving us to deal with the problem. We contacted them as soon as things were under control; asked them to put everything away as we were to cross the mountains at a lower altitude than normal so it might be turbulent. Remainder of the flight was flown normally with an uneventful landing.
Second reporter narrative
I did experince some hypoxia symptoms (tingling skin and a sensation of warmth); and after landing experienced a strong headache.
More incidents for this aircraft family →
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.