Narrative:

During boarding, the cabin temperature was uncomfortably high and little or no cooling air was being provided by the APU. Flow indications on both sides were normal. When both air conditioning supply switches were turned off for engine start, the pneumatic pressure was insufficient for a safe start so a start-cart was used. After power back, I found that 1.06 EPR per engine was the minimum power required to produce any cooling airflow from the packs. I taxied from gate to runway 18L at this power to get the cabin temperature under control. This procedure required that the brakes be used almost continuously during taxi. The brake temperatures were monitored constantly during the entire process, and remained around 125-150 the entire time. After we had reached the runway hold line and were stopped, the brake temperatures on the left main wheels began to climb and reached 330 degrees on the outboard wheel. A delay of 40 mins was incurred while the brakes were allowed to cool with crash fire rescue equipment standing by and were inspected by company maintenance. This aircraft had 5 E6 write-ups over the previous 7 days for the APU producing insufficient or no air and all were signed off as operations checked normal. I don't know how else I could have handled this situation other than to refuse to take the aircraft based on the previous E6 entries and the current cabin temperature but this was not perceived as a safety issue although it later became one because of the brakes. When we arrived at lga, maintenance said they were going to replace the APU that night.

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Original NASA ASRS Text

Title: AN S80 CAPT USES EXCESSIVE BRAKING AND INCURS A 50 MIN DELAY FOR BRAKE COOLING PURPOSES. THE APU AIR USED FOR AIR CONDITIONING PURPOSES WAS TOO LOW. SINCE THE CABIN WAS VERY HOT, HE HAD TO USE EXCESSIVE ENG PWR TO KEEP THE PAX COOL.

Narrative: DURING BOARDING, THE CABIN TEMP WAS UNCOMFORTABLY HIGH AND LITTLE OR NO COOLING AIR WAS BEING PROVIDED BY THE APU. FLOW INDICATIONS ON BOTH SIDES WERE NORMAL. WHEN BOTH AIR CONDITIONING SUPPLY SWITCHES WERE TURNED OFF FOR ENG START, THE PNEUMATIC PRESSURE WAS INSUFFICIENT FOR A SAFE START SO A START-CART WAS USED. AFTER PWR BACK, I FOUND THAT 1.06 EPR PER ENG WAS THE MINIMUM PWR REQUIRED TO PRODUCE ANY COOLING AIRFLOW FROM THE PACKS. I TAXIED FROM GATE TO RWY 18L AT THIS PWR TO GET THE CABIN TEMP UNDER CTL. THIS PROC REQUIRED THAT THE BRAKES BE USED ALMOST CONTINUOUSLY DURING TAXI. THE BRAKE TEMPS WERE MONITORED CONSTANTLY DURING THE ENTIRE PROCESS, AND REMAINED AROUND 125-150 THE ENTIRE TIME. AFTER WE HAD REACHED THE RWY HOLD LINE AND WERE STOPPED, THE BRAKE TEMPS ON THE L MAIN WHEELS BEGAN TO CLB AND REACHED 330 DEGS ON THE OUTBOARD WHEEL. A DELAY OF 40 MINS WAS INCURRED WHILE THE BRAKES WERE ALLOWED TO COOL WITH CFR STANDING BY AND WERE INSPECTED BY COMPANY MAINT. THIS ACFT HAD 5 E6 WRITE-UPS OVER THE PREVIOUS 7 DAYS FOR THE APU PRODUCING INSUFFICIENT OR NO AIR AND ALL WERE SIGNED OFF AS OPS CHKED NORMAL. I DON'T KNOW HOW ELSE I COULD HAVE HANDLED THIS SIT OTHER THAN TO REFUSE TO TAKE THE ACFT BASED ON THE PREVIOUS E6 ENTRIES AND THE CURRENT CABIN TEMP BUT THIS WAS NOT PERCEIVED AS A SAFETY ISSUE ALTHOUGH IT LATER BECAME ONE BECAUSE OF THE BRAKES. WHEN WE ARRIVED AT LGA, MAINT SAID THEY WERE GOING TO REPLACE THE APU THAT NIGHT.

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.