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An air carrier B727 flight crew descended below their assigned altitude when the autoplt failed to capture the altitude.
| Attributes | |
| ACN | 433023 |
| Time | |
| Date | 199904 |
| Day | Fri |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | navaid : cqy.vortac |
| State Reference | TX |
| Altitude | msl bound lower : 27750 msl bound upper : 28000 |
| Environment | |
| Flight Conditions | Mixed |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zfw.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B727 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other vortac |
| Flight Phase | descent : intermediate altitude |
| Route In Use | enroute : direct |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : second officer |
| Qualification | pilot : flight engineer pilot : instrument pilot : multi engine pilot : atp pilot : commercial |
| Experience | flight time last 90 days : 100 flight time total : 7000 flight time type : 2000 |
| ASRS Report | 433023 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | altitude deviation : overshoot non adherence : clearance non adherence : far |
| Independent Detector | other flight crewa other flight crewb |
| Resolutory Action | flight crew : returned to original clearance |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
Assigned a descent to FL280. First officer flying, captain on radios, flight engineer copying ATIS. Descent made on autoplt, proper (29.92) altimeter set, autoplt failed to level off at FL280, descended approximately 250 ft below before first officer noticed and returned to FL280. Autoplt capture may have failed due to higher than normal speed (mach .84), although rate of descent was normal. As flight engineer, I could have been more in the loop, if I had copied ATIS prior to descent.
Original NASA ASRS Text
Title: AN ACR B727 FLC DSNDED BELOW THEIR ASSIGNED ALT WHEN THE AUTOPLT FAILED TO CAPTURE THE ALT.
Narrative: ASSIGNED A DSCNT TO FL280. FO FLYING, CAPT ON RADIOS, FE COPYING ATIS. DSCNT MADE ON AUTOPLT, PROPER (29.92) ALTIMETER SET, AUTOPLT FAILED TO LEVEL OFF AT FL280, DSNDED APPROX 250 FT BELOW BEFORE FO NOTICED AND RETURNED TO FL280. AUTOPLT CAPTURE MAY HAVE FAILED DUE TO HIGHER THAN NORMAL SPD (MACH .84), ALTHOUGH RATE OF DSCNT WAS NORMAL. AS FE, I COULD HAVE BEEN MORE IN THE LOOP, IF I HAD COPIED ATIS PRIOR TO DSCNT.
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.