A B737-500 APU pneumatic system was deactivated per the MEL by deactivating the pneumatic valve clos...

Attributes
ACN	587934
Time
Date	200307
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Environment
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-500
Operating Under FAR Part	Part 121
Flight Phase	ground : maintenance
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	maintenance : technician oversight : supervisor
ASRS Report	587934
Person 2
Affiliation	company : air carrier
Function	other personnel other
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : apu duct pressure indicator
Resolutory Action	none taken : detected after the fact
Consequence	other Other
Factors
Maintenance	contributing factor : schedule pressure performance deficiency : fault isolation performance deficiency : unqualified personnel performance deficiency : logbook entry
Supplementary
Problem Areas	Maintenance Human Performance Aircraft Chart Or Publication
Primary Problem	Maintenance Human Performance

Narrative:

Flight crew had reported #1 engine difficult to start with APU. I used MEL reference 4950A to deactivate APU bleed. However, 4950A deals specifically with the APU bleed valve itself, not the APU bleed system. In considering my decision to use this MEL, I may have made a mistake, in that there is no MEL for the bleed system in its entirety. I have called line maintenance control, and asked to have the discrepancy assigned to the next maintenance station for further troubleshooting of the bleed system. The line maintenance controller feels that my use of the MEL is appropriate, but he agreed to assign the item as requested.

Original NASA ASRS Text

Title: A B737-500 APU PNEUMATIC SYS WAS DEACTIVATED PER THE MEL BY DEACTIVATING THE PNEUMATIC VALVE CLOSED.

Narrative: FLT CREW HAD RPTED #1 ENG DIFFICULT TO START WITH APU. I USED MEL REF 4950A TO DEACTIVATE APU BLEED. HOWEVER, 4950A DEALS SPECIFICALLY WITH THE APU BLEED VALVE ITSELF, NOT THE APU BLEED SYS. IN CONSIDERING MY DECISION TO USE THIS MEL, I MAY HAVE MADE A MISTAKE, IN THAT THERE IS NO MEL FOR THE BLEED SYS IN ITS ENTIRETY. I HAVE CALLED LINE MAINT CTL, AND ASKED TO HAVE THE DISCREPANCY ASSIGNED TO THE NEXT MAINT STATION FOR FURTHER TROUBLESHOOTING OF THE BLEED SYS. THE LINE MAINT CTLR FEELS THAT MY USE OF THE MEL IS APPROPRIATE, BUT HE AGREED TO ASSIGN THE ITEM AS REQUESTED.

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 B737-500 APU pneumatic system was deactivated per the MEL by deactivating the pneumatic valve closed.