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A saab-340 was dispatched with the duct temperature indicator inoperative and deferred in conflict with the MEL. Indicator monitors air cycle machine output.
| Attributes | |
| ACN | 681504 |
| Time | |
| Date | 200512 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | agl single value : 0 |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | Saab-Scania Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | ground : maintenance |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | maintenance : technician |
| Qualification | technician : powerplant technician : airframe |
| Experience | maintenance technician : 17 |
| ASRS Report | 681504 |
| Events | |
| Anomaly | aircraft equipment problem : critical maintenance problem : non compliance with mel non adherence : far non adherence : published procedure |
| Independent Detector | other flight crewa other flight crewb |
| Resolutory Action | none taken : detected after the fact |
| Consequence | other |
| Factors | |
| Maintenance | contributing factor : schedule pressure performance deficiency : non compliance with legal requirements performance deficiency : logbook entry |
| Supplementary | |
| Problem Areas | Maintenance Human Performance Aircraft Chart Or Publication |
| Primary Problem | Maintenance Human Performance |
Narrative:
A shared gauge for cabin temperature and duct temperature. The duct temperature outlet side of acm was inoperative. Temperature was ctlable. The faulty gauge could be deferred for cabin temperature; why not duct temperature by reason? It's the same gauge; use depends on switch position. Acm inlet overtemp warning are still working. This gauge only really allows pilots to observe the efficiency of acm output to cabin temperature ratio. I would request a change to the MEL manual so that no one else could make this mistake. If power to the gauge was lost; someone might defer the cabin temperature gauge which is allowed; and unknowingly remove the acm outlet duct temperature to go unmonitored.
Original NASA ASRS Text
Title: A SAAB-340 WAS DISPATCHED WITH THE DUCT TEMP INDICATOR INOP AND DEFERRED IN CONFLICT WITH THE MEL. INDICATOR MONITORS AIR CYCLE MACHINE OUTPUT.
Narrative: A SHARED GAUGE FOR CABIN TEMP AND DUCT TEMP. THE DUCT TEMP OUTLET SIDE OF ACM WAS INOP. TEMP WAS CTLABLE. THE FAULTY GAUGE COULD BE DEFERRED FOR CABIN TEMP; WHY NOT DUCT TEMP BY REASON? IT'S THE SAME GAUGE; USE DEPENDS ON SWITCH POS. ACM INLET OVERTEMP WARNING ARE STILL WORKING. THIS GAUGE ONLY REALLY ALLOWS PLTS TO OBSERVE THE EFFICIENCY OF ACM OUTPUT TO CABIN TEMP RATIO. I WOULD REQUEST A CHANGE TO THE MEL MANUAL SO THAT NO ONE ELSE COULD MAKE THIS MISTAKE. IF PWR TO THE GAUGE WAS LOST; SOMEONE MIGHT DEFER THE CABIN TEMP GAUGE WHICH IS ALLOWED; AND UNKNOWINGLY REMOVE THE ACM OUTLET DUCT TEMP TO GO UNMONITORED.
Data retrieved from NASA's ASRS site as of January 2009 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.