A B757 first officer reported a loss in pressurization over somewhat mountainous terrain in the vici...

Attributes
ACN	481151
Time
Date	200008
Day	Sun
Place
Locale Reference	navaid : als.vor
State Reference	NM
Altitude	msl bound lower : 20000 msl bound upper : 35000
Aircraft 1
Controlling Facilities	artcc : zab.artcc
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other other vortac
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial
ASRS Report	481151
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	other flight crewa other flight crewb
Resolutory Action	aircraft : equipment problem dissipated controller : issued new clearance flight crew : diverted to another airport flight crew : overcame equipment problem
Consequence	other other
Supplementary
Problem Areas	Maintenance Human Performance Aircraft Company
Primary Problem	Aircraft

Narrative:

At cruise FL350, 'right pack off' light on. 5 min cool, per procedure. Reset did not work. As captain/first officer reviewing MEL, 'left pack inoperative' and 'off' light on. Cabin began climbing 1200 FPM. Descent initiated. ATC advised immediate descent clearance to FL280. Requested MVA for terrain obstruction clearance. Grid minimum off-route altitude was 16.5 NM for that area. Further dscnts eventually to FL200. Turned south toward abq for lower terrain and better WX. After FL230, packs were reset and intermittently on. At top of descent, captain deployed passenger oxygen masks. Cabin altitude never above 10000 ft, no horn, etc. Sporadic pack operation enough to keep cabin altitude below 10000 ft. ACARS coverage lost in descent. ATC provided abq WX/ATIS. APU would not start in descent. APU and air conditioning packs had been repeat write-ups. Normal landing abq. Commend flight attendants for quick and calm performance of duties.

Original NASA ASRS Text

Title: A B757 FO RPTED A LOSS IN PRESSURIZATION OVER SOMEWHAT MOUNTAINOUS TERRAIN IN THE VICINITY OF ABQ.

Narrative: AT CRUISE FL350, 'R PACK OFF' LIGHT ON. 5 MIN COOL, PER PROC. RESET DID NOT WORK. AS CAPT/FO REVIEWING MEL, 'L PACK INOP' AND 'OFF' LIGHT ON. CABIN BEGAN CLBING 1200 FPM. DSCNT INITIATED. ATC ADVISED IMMEDIATE DSCNT CLRNC TO FL280. REQUESTED MVA FOR TERRAIN OBSTRUCTION CLRNC. GRID MINIMUM OFF-RTE ALT WAS 16.5 NM FOR THAT AREA. FURTHER DSCNTS EVENTUALLY TO FL200. TURNED S TOWARD ABQ FOR LOWER TERRAIN AND BETTER WX. AFTER FL230, PACKS WERE RESET AND INTERMITTENTLY ON. AT TOP OF DSCNT, CAPT DEPLOYED PAX OXYGEN MASKS. CABIN ALT NEVER ABOVE 10000 FT, NO HORN, ETC. SPORADIC PACK OP ENOUGH TO KEEP CABIN ALT BELOW 10000 FT. ACARS COVERAGE LOST IN DSCNT. ATC PROVIDED ABQ WX/ATIS. APU WOULD NOT START IN DSCNT. APU AND AIR CONDITIONING PACKS HAD BEEN REPEAT WRITE-UPS. NORMAL LNDG ABQ. COMMEND FLT ATTENDANTS FOR QUICK AND CALM PERFORMANCE OF DUTIES.

Data retrieved from NASA's ASRS site as of July 2007 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.

A B757 first officer reported a loss in pressurization over somewhat mountainous terrain in the vicinity of abq.