First officer of B737 reports that company pressured flight crew to fly at FL350 with air conditioni...

Attributes
ACN	628143
Time
Date	200408
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : oak.airport
State Reference	CA
Altitude	agl single value : 0
Environment
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-400
Operating Under FAR Part	Part 121
Flight Phase	ground : parked
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
ASRS Report	628143
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	aircraft equipment problem : critical maintenance problem : non compliance with mel maintenance problem : improper maintenance non adherence : far
Independent Detector	aircraft equipment other aircraft equipment : cabin altitude indicator
Resolutory Action	flight crew : overrode automation flight crew : overcame equipment problem
Consequence	other other
Factors
Maintenance	contributing factor : engineering procedure contributing factor : schedule pressure performance deficiency : logbook entry performance deficiency : fault isolation
Supplementary
Problem Areas	Maintenance Human Performance Flight Crew Human Performance Company Aircraft
Primary Problem	Aircraft

Narrative:

Aircraft already had MEL 21-6A, which restr the use of the left pack. On preflight, we discovered the high mode of the right pack was inoperative. MEL 21-2C was added, which includes an operations note in 2 different places of the MEL (one at the beginning, repeated again at the end) to adhere to the restrs of MEL 21-1 for single pack operation. From a system sense, this makes sense because if the left pack failed in-flight, the right pack would try to go to the high mode, which was inoperative, so we would go from 2 packs to no packs all at once. The captain explained this along with his desire to fly at FL250 instead of FL350 to dispatch, maintenance control, and the flight operations agent, our FMS showed this would take an additional 700 pounds of fuel, which we already had on board. Dispatch said it would take over 2000 pounds extra to go at FL240, possibly because they plugged in .74 mach or some other speed than economy, which the FMS uses. Maintenance control claimed the operations note did not apply because the pack worked fine in automatic -- it was just the high mode that was inoperative. The captain suggested operating at FL250 or below because that was the safest solution to the confusion, but everyone disagreed because of the extra 700 pounds of fuel. The flight operations agent agreed to follow up to try to clarify the MEL. The captain agreed to operate at FL350 because the flight operations agent supported going to FL350. We took off with the left pack off per MEL 21-6A and the right pack in automatic. As soon as we were airborne, the airflow from the right pack shut off as it tried to automatically go into the high mode, which it is designed to do, but the high mode was inoperative. After flap retraction, we turned the left pack on per MEL 21-6A and the airflow from both packs was restored. During the approach into portland, we turned off the left pack per MEL 21-6A, and once again the right pack immediately shut down as well.

Original NASA ASRS Text

Title: FO OF B737 RPTS THAT COMPANY PRESSURED FLT CREW TO FLY AT FL350 WITH AIR CONDITIONING PACK WRITE-UPS AND MEL ITEMS ON BOTH PACKS. TWICE DURING THE SUBSEQUENT FLT, BOTH PACKS WERE SIMULTANEOUSLY INOP.

Narrative: ACFT ALREADY HAD MEL 21-6A, WHICH RESTR THE USE OF THE L PACK. ON PREFLT, WE DISCOVERED THE HIGH MODE OF THE R PACK WAS INOP. MEL 21-2C WAS ADDED, WHICH INCLUDES AN OPS NOTE IN 2 DIFFERENT PLACES OF THE MEL (ONE AT THE BEGINNING, REPEATED AGAIN AT THE END) TO ADHERE TO THE RESTRS OF MEL 21-1 FOR SINGLE PACK OP. FROM A SYS SENSE, THIS MAKES SENSE BECAUSE IF THE L PACK FAILED INFLT, THE R PACK WOULD TRY TO GO TO THE HIGH MODE, WHICH WAS INOP, SO WE WOULD GO FROM 2 PACKS TO NO PACKS ALL AT ONCE. THE CAPT EXPLAINED THIS ALONG WITH HIS DESIRE TO FLY AT FL250 INSTEAD OF FL350 TO DISPATCH, MAINT CTL, AND THE FLIGHT OPS AGENT, OUR FMS SHOWED THIS WOULD TAKE AN ADDITIONAL 700 LBS OF FUEL, WHICH WE ALREADY HAD ON BOARD. DISPATCH SAID IT WOULD TAKE OVER 2000 LBS EXTRA TO GO AT FL240, POSSIBLY BECAUSE THEY PLUGGED IN .74 MACH OR SOME OTHER SPD THAN ECONOMY, WHICH THE FMS USES. MAINT CTL CLAIMED THE OPS NOTE DID NOT APPLY BECAUSE THE PACK WORKED FINE IN AUTO -- IT WAS JUST THE HIGH MODE THAT WAS INOP. THE CAPT SUGGESTED OPERATING AT FL250 OR BELOW BECAUSE THAT WAS THE SAFEST SOLUTION TO THE CONFUSION, BUT EVERYONE DISAGREED BECAUSE OF THE EXTRA 700 LBS OF FUEL. THE FLIGHT OPS AGENT AGREED TO FOLLOW UP TO TRY TO CLARIFY THE MEL. THE CAPT AGREED TO OPERATE AT FL350 BECAUSE THE FLIGHT OPS AGENT SUPPORTED GOING TO FL350. WE TOOK OFF WITH THE L PACK OFF PER MEL 21-6A AND THE R PACK IN AUTO. AS SOON AS WE WERE AIRBORNE, THE AIRFLOW FROM THE R PACK SHUT OFF AS IT TRIED TO AUTOMATICALLY GO INTO THE HIGH MODE, WHICH IT IS DESIGNED TO DO, BUT THE HIGH MODE WAS INOP. AFTER FLAP RETRACTION, WE TURNED THE L PACK ON PER MEL 21-6A AND THE AIRFLOW FROM BOTH PACKS WAS RESTORED. DURING THE APCH INTO PORTLAND, WE TURNED OFF THE LEFT PACK PER MEL 21-6A, AND ONCE AGAIN THE R PACK IMMEDIATELY SHUT DOWN AS WELL.

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.

First officer of B737 reports that company pressured flight crew to fly at FL350 with air conditioning pack write-ups and MEL items on both packs. Twice during the subsequent flight, both packs were simultaneously inoperative.