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Altitude deviation. During descent, flight crew overshot assigned altitude, descended 500 ft below, but corrected back. Reporter first officer attributes inoperative autoplt and flight crew fatigue as contributing.
| Attributes | |
| ACN | 339860 |
| Time | |
| Date | 199606 |
| Day | Thu |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : maf |
| State Reference | TX |
| Altitude | msl bound lower : 13500 msl bound upper : 14000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tracon : maf |
| Operator | common carrier : air carrier |
| Make Model Name | DC-9 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent other |
| Route In Use | enroute airway : zfw |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument pilot : flight engineer |
| Experience | flight time last 90 days : 200 flight time total : 10000 flight time type : 4000 |
| ASRS Report | 339860 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | altitude deviation : overshoot non adherence : clearance |
| Independent Detector | other flight crewa other other : unspecified cockpit |
| Resolutory Action | flight crew : returned to intended course or assigned course |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
DC9, descent pilot's discretion FL280 to 14000 ft inbound for maf. ZFW give us a frequency change to maf approach. We notice an altitude alert light and see we are at 13500 ft. We quickly correct to 14000 ft and check in with approach and are given descent to 8000 ft. This particular night, neither the captain nor I heard the aural warning for 1000 ft to go. The autoplt was inoperative which I believe was a contributing factor. The autoplt had been MEL'ed since jun/xx/96. I believe this to be way too long, although our books allow for it to go up to 10 calendar days. I do not believe an autoplt should be allowed to fly inoperative more than 3 days at the most. Altitude capture capability would have also prevented this situation. Inoperative autoplts are also difficult on longer flts at the high altitudes causing fatigue to set in much more quickly and setting the crew up for altdevs or worse. Even navigation and map reading are more difficult.
Original NASA ASRS Text
Title: ALTDEV. DURING DSCNT, FLC OVERSHOT ASSIGNED ALT, DSNDED 500 FT BELOW, BUT CORRECTED BACK. RPTR FO ATTRIBUTES INOP AUTOPLT AND FLC FATIGUE AS CONTRIBUTING.
Narrative: DC9, DSCNT PLT'S DISCRETION FL280 TO 14000 FT INBOUND FOR MAF. ZFW GIVE US A FREQ CHANGE TO MAF APCH. WE NOTICE AN ALT ALERT LIGHT AND SEE WE ARE AT 13500 FT. WE QUICKLY CORRECT TO 14000 FT AND CHK IN WITH APCH AND ARE GIVEN DSCNT TO 8000 FT. THIS PARTICULAR NIGHT, NEITHER THE CAPT NOR I HEARD THE AURAL WARNING FOR 1000 FT TO GO. THE AUTOPLT WAS INOP WHICH I BELIEVE WAS A CONTRIBUTING FACTOR. THE AUTOPLT HAD BEEN MEL'ED SINCE JUN/XX/96. I BELIEVE THIS TO BE WAY TOO LONG, ALTHOUGH OUR BOOKS ALLOW FOR IT TO GO UP TO 10 CALENDAR DAYS. I DO NOT BELIEVE AN AUTOPLT SHOULD BE ALLOWED TO FLY INOP MORE THAN 3 DAYS AT THE MOST. ALT CAPTURE CAPABILITY WOULD HAVE ALSO PREVENTED THIS SIT. INOP AUTOPLTS ARE ALSO DIFFICULT ON LONGER FLTS AT THE HIGH ALTS CAUSING FATIGUE TO SET IN MUCH MORE QUICKLY AND SETTING THE CREW UP FOR ALTDEVS OR WORSE. EVEN NAV AND MAP READING ARE MORE DIFFICULT.
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.