|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||0601 To 1200|
|Locale Reference||airport : ama.airport|
|Altitude||msl single value : 24000|
|Controlling Facilities||artcc : zab.artcc|
tower : mgw.tower
|Operator||common carrier : air carrier|
|Make Model Name||B737-300|
|Operating Under FAR Part||Part 121|
|Flight Phase||cruise : level|
|Affiliation||company : air carrier|
|Function||flight crew : captain|
oversight : pic
|Qualification||pilot : atp|
|Experience||flight time last 90 days : 270|
flight time total : 11500
flight time type : 6500
|Affiliation||company : air carrier|
|Function||flight crew : first officer|
|Anomaly||aircraft equipment problem : less severe|
|Independent Detector||aircraft equipment other aircraft equipment : pac trip off light|
|Resolutory Action||flight crew : landed as precaution|
flight crew : diverted to another airport
|Problem Areas||Flight Crew Human Performance|
We departed mci operating under MEL 21-1, single pack operation. The right pack was written up inoperative the previous day. During cruise flight at FL240, approximately 135 NM north of ama, we noticed a pack trip off light illuminated and that the cabin altitude was ascending at a rapid rate. We donned the oxygen mask and initiated a rapid descent to 10000 ft MSL. We tried to get the left pack to reset, but it would not remain operational. We got the cabin altitude stabilized at 10000 ft MSL and turned to ama. We tried numerous times to reach dispatch and ama operations with no success. We had ZAB call dispatch to inform them of our problem and diversion to ama. Shortly after the center call request to dispatch, another company flight on company frequency called dispatch for a relay as well. Approximately 35 NM from ama, we established contact with dispatch and amended the release to show ama as the destination. We ran the checklist for depressurization, dual pack failure prior to landing. During the descent, the flight attendants noticed the rapid descent and called the cockpit, basically shortly after we pushed over to go down. The flight attendants remained calm and professional during the event and kept the passenger calm as a result. We made a couple of PA's en route to ama telling the passenger of our problem, diversion and stressing each time that the problem was under control and the aircraft was safe for flight. Company mechanics met us at arrival and fixed both packs and we departed. All of the passenger seemed calm and none expressed any anxiety or reservation of re-boarding for the rest of the flight. The event worked out very well due to the very proficient first officer and cabin crew working in an outstanding manner. In hindsight, we never declared an emergency. ATC immediately gave us the lower altitude during the descent and after things had calmed/slowed down asked if we wanted to declare an emergency and I elected at that point to decline. I now wish we had declared an emergency during the initial lower altitude request. I know that acar's is being introduced online and the sooner the better, for it would have helped free up a lot of time and cockpit attention during our problem.
Original NASA ASRS Text
Title: A B737-300 FLT CREW, WHILE OPERATING WITH ONLY 1 PACK, EXPERIENCES A FAILURE OF THE OTHER PACK.
Narrative: WE DEPARTED MCI OPERATING UNDER MEL 21-1, SINGLE PACK OP. THE R PACK WAS WRITTEN UP INOP THE PREVIOUS DAY. DURING CRUISE FLT AT FL240, APPROX 135 NM N OF AMA, WE NOTICED A PACK TRIP OFF LIGHT ILLUMINATED AND THAT THE CABIN ALT WAS ASCENDING AT A RAPID RATE. WE DONNED THE OXYGEN MASK AND INITIATED A RAPID DSCNT TO 10000 FT MSL. WE TRIED TO GET THE L PACK TO RESET, BUT IT WOULD NOT REMAIN OPERATIONAL. WE GOT THE CABIN ALT STABILIZED AT 10000 FT MSL AND TURNED TO AMA. WE TRIED NUMEROUS TIMES TO REACH DISPATCH AND AMA OPS WITH NO SUCCESS. WE HAD ZAB CALL DISPATCH TO INFORM THEM OF OUR PROB AND DIVERSION TO AMA. SHORTLY AFTER THE CTR CALL REQUEST TO DISPATCH, ANOTHER COMPANY FLT ON COMPANY FREQ CALLED DISPATCH FOR A RELAY AS WELL. APPROX 35 NM FROM AMA, WE ESTABLISHED CONTACT WITH DISPATCH AND AMENDED THE RELEASE TO SHOW AMA AS THE DEST. WE RAN THE CHKLIST FOR DEPRESSURIZATION, DUAL PACK FAILURE PRIOR TO LNDG. DURING THE DSCNT, THE FLT ATTENDANTS NOTICED THE RAPID DSCNT AND CALLED THE COCKPIT, BASICALLY SHORTLY AFTER WE PUSHED OVER TO GO DOWN. THE FLT ATTENDANTS REMAINED CALM AND PROFESSIONAL DURING THE EVENT AND KEPT THE PAX CALM AS A RESULT. WE MADE A COUPLE OF PA'S ENRTE TO AMA TELLING THE PAX OF OUR PROB, DIVERSION AND STRESSING EACH TIME THAT THE PROB WAS UNDER CTL AND THE ACFT WAS SAFE FOR FLT. COMPANY MECHS MET US AT ARR AND FIXED BOTH PACKS AND WE DEPARTED. ALL OF THE PAX SEEMED CALM AND NONE EXPRESSED ANY ANXIETY OR RESERVATION OF RE-BOARDING FOR THE REST OF THE FLT. THE EVENT WORKED OUT VERY WELL DUE TO THE VERY PROFICIENT FO AND CABIN CREW WORKING IN AN OUTSTANDING MANNER. IN HINDSIGHT, WE NEVER DECLARED AN EMER. ATC IMMEDIATELY GAVE US THE LOWER ALT DURING THE DSCNT AND AFTER THINGS HAD CALMED/SLOWED DOWN ASKED IF WE WANTED TO DECLARE AN EMER AND I ELECTED AT THAT POINT TO DECLINE. I NOW WISH WE HAD DECLARED AN EMER DURING THE INITIAL LOWER ALT REQUEST. I KNOW THAT ACAR'S IS BEING INTRODUCED ONLINE AND THE SOONER THE BETTER, FOR IT WOULD HAVE HELPED FREE UP A LOT OF TIME AND COCKPIT ATTN DURING OUR PROB.
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.