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A CL65 flight crew initiate a 1000 ft descent at a rate of 4000 FPM which resulted in the aircraft overshooting assigned altitude by 300 ft.
| Attributes | |
| ACN | 594525 |
| Time | |
| Date | 200309 |
| Day | Tue |
| Place | |
| Locale Reference | atc facility : zid.artcc |
| State Reference | IN |
| Altitude | msl bound lower : 22700 msl bound upper : 23000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zid.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | Regional Jet CL65, Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent : intermediate altitude |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : multi engine pilot : instrument |
| Experience | flight time last 90 days : 250 flight time total : 3300 flight time type : 250 |
| ASRS Report | 594525 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Events | |
| Anomaly | altitude deviation : overshoot non adherence : far non adherence : clearance |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : overrode automation flight crew : returned to assigned altitude |
| Supplementary | |
| Problem Areas | Aircraft Flight Crew Human Performance |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
Level at 24000 ft, ATC asked us to descend to 23000 ft and to expedite the descent. I, as PNF, read this back, selected the altitude in the pre-selector and confirmed the altitude with the captain. The next time I looked at the instruments, we were in a 4000 FPM descent. I didn't say anything because the autoplt had quickly captured the altitude. The autoplt did this poorly, lowering and dipped down to 22700 ft. The captain then disconnected the autoplt and climbed back up to 23000 ft. The biggest mistake here was to initiate a 4000 FPM descent for 1000 ft of altitude difference. Simply following the aim, which states 500-1500 ft should be used, would solve this problem.
Original NASA ASRS Text
Title: A CL65 FLT CREW INITIATE A 1000 FT DSCNT AT A RATE OF 4000 FPM WHICH RESULTED IN THE ACFT OVERSHOOTING ASSIGNED ALT BY 300 FT.
Narrative: LEVEL AT 24000 FT, ATC ASKED US TO DSND TO 23000 FT AND TO EXPEDITE THE DSCNT. I, AS PNF, READ THIS BACK, SELECTED THE ALT IN THE PRE-SELECTOR AND CONFIRMED THE ALT WITH THE CAPT. THE NEXT TIME I LOOKED AT THE INSTS, WE WERE IN A 4000 FPM DSCNT. I DIDN'T SAY ANYTHING BECAUSE THE AUTOPLT HAD QUICKLY CAPTURED THE ALT. THE AUTOPLT DID THIS POORLY, LOWERING AND DIPPED DOWN TO 22700 FT. THE CAPT THEN DISCONNECTED THE AUTOPLT AND CLBED BACK UP TO 23000 FT. THE BIGGEST MISTAKE HERE WAS TO INITIATE A 4000 FPM DSCNT FOR 1000 FT OF ALT DIFFERENCE. SIMPLY FOLLOWING THE AIM, WHICH STATES 500-1500 FT SHOULD BE USED, WOULD SOLVE THIS PROB.
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.