A B737-300 PIC elects to use an MEL'ed air conditioning pack when the remaining pack is not pressuri...

Attributes
ACN	456341
Time
Date	199912
Day	Wed
Local Time Of Day	0601 To 1200
Place
State Reference	TX
Altitude	msl single value : 9000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zfw.artcc tower : mdw.tower
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 14000 flight time type : 5000
ASRS Report	456341
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 160 flight time total : 7000 flight time type : 400
ASRS Report	456530
Events
Anomaly	aircraft equipment problem : critical maintenance problem : non compliance with mel non adherence : far non adherence : company policies
Independent Detector	other flight crewa other flight crewb
Resolutory Action	flight crew : overcame equipment problem other
Consequence	faa : reviewed incident with flight crew other
Supplementary
Problem Areas	Aircraft Company Flight Crew Human Performance Maintenance Human Performance
Primary Problem	Aircraft

Narrative:

On dec/xa/99, we began the third day of a 4 day trip in el paso, tx. Our first leg was from elp to dfw departing at AB45. We began our preflight at approximately AB05 and were told that an FAA safety inspector would be with us on the leg to dfw. As I did the walkaround inspection, I noticed that the r-hand ram air door was closed (not normal for ground operation). When I checked the aircraft logbook, the crew that brought the aircraft in the previous night had written the 'right-hand ram air door as being closed on the ground' and had ground crew placard the r-hand pack inoperative. During our cockpit preflight, we discussed operation with the l-hand pack as inoperative, and flight control filed us at an altitude (FL240) which was safe for 1 pack operation. We were also working another unrelated mechanical problem with maintenance over the telephone. Taxi and takeoff were normal except for being about 25 mins late. As I was running the after takeoff checklist, I noticed that the l-hand pack was not pressurizing the aircraft. The cabin altitude was approximately the same aircraft altitude (8500 ft MSL). I told the first officer to level at 10000 ft MSL. At this point I had 2 options: 1) return to elp unpressurized or 2) see if the r-hand pack would pressurize. I elected to go with option #2. It pressurized the aircraft. I left the APU running as backup and we continued to dfw with no further problems. Supplemental information from acn 456530: MEL procedures require the crew to close the air conditioning isolation valve, keep the affected pack off for takeoff, and power the left pack from the APU with the #1 engine bleed switch off. The left pack appeared to operate normally. After takeoff, we again complied with MEL procedures and reconfigured the pneumatic bleeds. Confirming that all switches were properly configured, and recognizing that the airplane was not pressurizing, the captain elected to turn on the right pack with the left pack still on. Upon landing at dfw, we immediately turned off the r-hand pack and again closed the isolation valve to comply with MEL procedures.

Original NASA ASRS Text

Title: A B737-300 PIC ELECTS TO USE AN MEL'ED AIR CONDITIONING PACK WHEN THE REMAINING PACK IS NOT PRESSURIZING THE ACFT AT 9000 FT AFTER DEPARTING ELP, TX. ACR INSPECTOR ON BOARD.

Narrative: ON DEC/XA/99, WE BEGAN THE THIRD DAY OF A 4 DAY TRIP IN EL PASO, TX. OUR FIRST LEG WAS FROM ELP TO DFW DEPARTING AT AB45. WE BEGAN OUR PREFLT AT APPROX AB05 AND WERE TOLD THAT AN FAA SAFETY INSPECTOR WOULD BE WITH US ON THE LEG TO DFW. AS I DID THE WALKAROUND INSPECTION, I NOTICED THAT THE R-HAND RAM AIR DOOR WAS CLOSED (NOT NORMAL FOR GND OP). WHEN I CHKED THE ACFT LOGBOOK, THE CREW THAT BROUGHT THE ACFT IN THE PREVIOUS NIGHT HAD WRITTEN THE 'R-HAND RAM AIR DOOR AS BEING CLOSED ON THE GND' AND HAD GND CREW PLACARD THE R-HAND PACK INOP. DURING OUR COCKPIT PREFLT, WE DISCUSSED OP WITH THE L-HAND PACK AS INOP, AND FLT CTL FILED US AT AN ALT (FL240) WHICH WAS SAFE FOR 1 PACK OP. WE WERE ALSO WORKING ANOTHER UNRELATED MECHANICAL PROB WITH MAINT OVER THE TELEPHONE. TAXI AND TKOF WERE NORMAL EXCEPT FOR BEING ABOUT 25 MINS LATE. AS I WAS RUNNING THE AFTER TKOF CHKLIST, I NOTICED THAT THE L-HAND PACK WAS NOT PRESSURIZING THE ACFT. THE CABIN ALT WAS APPROX THE SAME ACFT ALT (8500 FT MSL). I TOLD THE FO TO LEVEL AT 10000 FT MSL. AT THIS POINT I HAD 2 OPTIONS: 1) RETURN TO ELP UNPRESSURIZED OR 2) SEE IF THE R-HAND PACK WOULD PRESSURIZE. I ELECTED TO GO WITH OPTION #2. IT PRESSURIZED THE ACFT. I LEFT THE APU RUNNING AS BACKUP AND WE CONTINUED TO DFW WITH NO FURTHER PROBS. SUPPLEMENTAL INFO FROM ACN 456530: MEL PROCS REQUIRE THE CREW TO CLOSE THE AIR CONDITIONING ISOLATION VALVE, KEEP THE AFFECTED PACK OFF FOR TKOF, AND PWR THE L PACK FROM THE APU WITH THE #1 ENG BLEED SWITCH OFF. THE L PACK APPEARED TO OPERATE NORMALLY. AFTER TKOF, WE AGAIN COMPLIED WITH MEL PROCS AND RECONFIGURED THE PNEUMATIC BLEEDS. CONFIRMING THAT ALL SWITCHES WERE PROPERLY CONFIGURED, AND RECOGNIZING THAT THE AIRPLANE WAS NOT PRESSURIZING, THE CAPT ELECTED TO TURN ON THE R PACK WITH THE L PACK STILL ON. UPON LNDG AT DFW, WE IMMEDIATELY TURNED OFF THE R-HAND PACK AND AGAIN CLOSED THE ISOLATION VALVE TO COMPLY WITH MEL PROCS.

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 B737-300 PIC elects to use an MEL'ed air conditioning pack when the remaining pack is not pressurizing the aircraft at 9000 ft after departing elp, tx. Air carrier inspector on board.