An SF340's engine bleeds tripped causing a loss of cabin pressure.

Attributes
ACN	798321
Time
Date	200807
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl single value : 17000
Aircraft 1
Controlling Facilities	artcc : zzz.artcc
Operator	common carrier : air carrier
Make Model Name	SF 340B
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial
ASRS Report	798321
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	flight crew : exited penetrated airspace flight crew : took evasive action
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

On the date of the incident; aircraft X had the altitude pre-selector deferred. The autoplt was being operated in the altitude hold mode level at 17000 ft. While in cruise flight the left bleed light came on. Bleed was cycled to reset and back to automatic. Moments later both right and left bleed lights illuminated. QRH directed us to descend to 10000 ft. ATC was notified and descent was begun. QRH also directed us to manually control the depressurization of the cabin. During this process some confusion was had as the cabin altitude began dropping rapidly; causing discomfort. While regulating the rate ATC handed us off to the next center controller.

Original NASA ASRS Text

Title: An SF340'S ENG BLEEDS TRIPPED CAUSING A LOSS OF CABIN PRESSURE.

Narrative: ON THE DATE OF THE INCIDENT; ACFT X HAD THE ALT PRE-SELECTOR DEFERRED. THE AUTOPLT WAS BEING OPERATED IN THE ALT HOLD MODE LEVEL AT 17000 FT. WHILE IN CRUISE FLT THE L BLEED LIGHT CAME ON. BLEED WAS CYCLED TO RESET AND BACK TO AUTO. MOMENTS LATER BOTH R AND L BLEED LIGHTS ILLUMINATED. QRH DIRECTED US TO DSND TO 10000 FT. ATC WAS NOTIFIED AND DSCNT WAS BEGUN. QRH ALSO DIRECTED US TO MANUALLY CTL THE DEPRESSURIZATION OF THE CABIN. DURING THIS PROCESS SOME CONFUSION WAS HAD AS THE CABIN ALT BEGAN DROPPING RAPIDLY; CAUSING DISCOMFORT. WHILE REGULATING THE RATE ATC HANDED US OFF TO THE NEXT CTR CTLR.

Data retrieved from NASA's ASRS site as of May 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.