F100 crew had low APU pneumatic pressure during engine start.

Attributes
ACN	502530
Time
Date	200102
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : dfw.airport
State Reference	TX
Altitude	agl single value : 0
Environment
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Fokker 100
Operating Under FAR Part	Part 121
Flight Phase	ground : parked ground other : engine start
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	502530
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument pilot : multi engine
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	other flight crewa other flight crewb
Resolutory Action	other
Consequence	other other
Supplementary
Problem Areas	Company Aircraft
Primary Problem	Company

Narrative:

APU lost pressure output. Arrived at the aircraft, checked the logbook -- clean. Completed checklist, prepared for a start to pwrback. Attempted to start #1. Due to low pressure, aborted start. Copilot asked if I wanted to call maintenance. I said 'no, ask for a tart cart.' I considered that reasonable due to the warm gusty conditions. Due to the position of the aircraft, there was also a tailwind. Hooked up the start cart, started engines and left. Wrong decision. Arrived at oma, started the APU, then noticed the pressure once again lower than normal. Turned off the packs. Pressure appeared to be normal around 44 psi. I elected to call maintenance as I was unsure as to the integrity of the system. The APU was placarded by contract maintenance. We incurred a 2 1/2 hour delay due to my wrong decision at the start. Had we called maintenance in dfw, sure we would have been delayed more, but not as long as our delay in oma. I guess part of my reasoning included that we were already 1 hour behind due to WX, due to a different aircraft with similar problems. I guess, in trying so hard not to make a wrong decision, I made a wrong decision.

Original NASA ASRS Text

Title: F100 CREW HAD LOW APU PNEUMATIC PRESSURE DURING ENG START.

Narrative: APU LOST PRESSURE OUTPUT. ARRIVED AT THE ACFT, CHKED THE LOGBOOK -- CLEAN. COMPLETED CHKLIST, PREPARED FOR A START TO PWRBACK. ATTEMPTED TO START #1. DUE TO LOW PRESSURE, ABORTED START. COPLT ASKED IF I WANTED TO CALL MAINT. I SAID 'NO, ASK FOR A TART CART.' I CONSIDERED THAT REASONABLE DUE TO THE WARM GUSTY CONDITIONS. DUE TO THE POSITION OF THE ACFT, THERE WAS ALSO A TAILWIND. HOOKED UP THE START CART, STARTED ENGS AND LEFT. WRONG DECISION. ARRIVED AT OMA, STARTED THE APU, THEN NOTICED THE PRESSURE ONCE AGAIN LOWER THAN NORMAL. TURNED OFF THE PACKS. PRESSURE APPEARED TO BE NORMAL AROUND 44 PSI. I ELECTED TO CALL MAINT AS I WAS UNSURE AS TO THE INTEGRITY OF THE SYS. THE APU WAS PLACARDED BY CONTRACT MAINT. WE INCURRED A 2 1/2 HR DELAY DUE TO MY WRONG DECISION AT THE START. HAD WE CALLED MAINT IN DFW, SURE WE WOULD HAVE BEEN DELAYED MORE, BUT NOT AS LONG AS OUR DELAY IN OMA. I GUESS PART OF MY REASONING INCLUDED THAT WE WERE ALREADY 1 HR BEHIND DUE TO WX, DUE TO A DIFFERENT ACFT WITH SIMILAR PROBS. I GUESS, IN TRYING SO HARD NOT TO MAKE A WRONG DECISION, I MADE A WRONG DECISION.

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.