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Captain of large transport air carrier aircraft inadvertently overshot descent altitude due to misprogramming the FMC system.
| Attributes | |
| ACN | 238533 |
| Time | |
| Date | 199304 |
| Day | Tue |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : den |
| State Reference | CO |
| Altitude | msl bound lower : 25700 msl bound upper : 26000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zdv |
| Operator | common carrier : air carrier |
| Make Model Name | Large Transport, Low Wing, 2 Turbojet Eng |
| Navigation In Use | Other Other |
| Flight Phase | cruise other descent other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 160 flight time total : 19000 flight time type : 160 |
| ASRS Report | 238533 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : flight engineer pilot : atp |
| Experience | flight time last 90 days : 250 flight time total : 8000 flight time type : 800 |
| ASRS Report | 238657 |
| Events | |
| Anomaly | altitude deviation : overshoot non adherence : clearance |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other controllera other flight crewa |
| Resolutory Action | flight crew : returned to intended course or assigned course other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
Descending into denver from cruise altitude of 37000 ft. Den WX was rain showers and small cumulo nimbus's moving over field from southwest to northeast. Flight was cleared from FL370 to FL330, then to FL290. FMC crz used for these dscnts. Flight then cleared to FL260, and flch used for this descent. Wind shift at den prompted holding clearance and runway change. Holding entered in FMC and while briefing new approach, aircraft descended slowly to about 25600 ft, at which time altitude alert sounded, and controller called. During return to FL260, both pilots noticed vertical speed window open, indicating 300 FPM down. Vertical speed function had not been used for any prior descent.
Original NASA ASRS Text
Title: CAPT OF LGT ACR ACFT INADVERTENTLY OVERSHOT DSCNT ALT DUE TO MISPROGRAMMING THE FMC SYS.
Narrative: DSNDING INTO DENVER FROM CRUISE ALT OF 37000 FT. DEN WX WAS RAIN SHOWERS AND SMALL CUMULO NIMBUS'S MOVING OVER FIELD FROM SW TO NE. FLT WAS CLRED FROM FL370 TO FL330, THEN TO FL290. FMC CRZ USED FOR THESE DSCNTS. FLT THEN CLRED TO FL260, AND FLCH USED FOR THIS DSCNT. WIND SHIFT AT DEN PROMPTED HOLDING CLRNC AND RWY CHANGE. HOLDING ENTERED IN FMC AND WHILE BRIEFING NEW APCH, ACFT DSNDED SLOWLY TO ABOUT 25600 FT, AT WHICH TIME ALT ALERT SOUNDED, AND CTLR CALLED. DURING RETURN TO FL260, BOTH PLTS NOTICED VERT SPD WINDOW OPEN, INDICATING 300 FPM DOWN. VERT SPD FUNCTION HAD NOT BEEN USED FOR ANY PRIOR 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.