 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
DC10 crew had an altitude deviation after the crew moved the vertical speed wheel after the autoplt had an altitude capture.
| Attributes | |
| ACN | 608932 |
| Time | |
| Date | 200402 |
| Day | Tue |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : sjc.airport |
| State Reference | CA |
| Altitude | msl bound lower : 4250 msl bound upper : 4500 |
| Environment | |
| Flight Conditions | IMC |
| Weather Elements | Turbulence Windshear |
| Light | Dusk |
| Aircraft 1 | |
| Controlling Facilities | tracon : nct.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | DC-10 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent : approach |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : flight engineer pilot : commercial pilot : atp |
| Experience | flight time last 90 days : 40 flight time total : 9000 flight time type : 1000 |
| ASRS Report | 608932 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude inflight encounter : turbulence inflight encounter : weather non adherence : company policies non adherence : far non adherence : published procedure other anomaly |
| Independent Detector | aircraft equipment other aircraft equipment : altimeters other flight crewa other flight crewb |
| Resolutory Action | flight crew : overrode automation flight crew : returned to assigned altitude flight crew : became reoriented |
| Supplementary | |
| Problem Areas | Aircraft Weather Flight Crew Human Performance |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
Cleared to 5500 ft (MSA in area), then cleared to slow to 200 KIAS, at 200 KIAS, descend to 4500 ft. Turbulence in clouds causing airspeed to fluctuate -20/+5 KTS of 200 KIAS. Vertical speed guidance used when speed decreased to considerably slower than desired. That action (rolling vertical speed wheel to regain speed) caused altitude capture function of autoplt to disarm. This resulted in a rapid descent below assigned altitude (of 250 ft). Both first officer and so called out deviation. Autoplt then disconnected, and aircraft manually flown back to assigned altitude. Causal event: 1) turbulence, 2) ATC assigned altitude 1000 ft below MSA for area, 3) improper use by PF of FGS. 4) fixation on low airspeed, resulting in #3 above. Corrective action: 1) proper use of FGS, especially in turbulence.
Original NASA ASRS Text
Title: DC10 CREW HAD AN ALTDEV AFTER THE CREW MOVED THE VERT SPD WHEEL AFTER THE AUTOPLT HAD AN ALT CAPTURE.
Narrative: CLRED TO 5500 FT (MSA IN AREA), THEN CLRED TO SLOW TO 200 KIAS, AT 200 KIAS, DSND TO 4500 FT. TURB IN CLOUDS CAUSING AIRSPD TO FLUCTUATE -20/+5 KTS OF 200 KIAS. VERT SPD GUIDANCE USED WHEN SPD DECREASED TO CONSIDERABLY SLOWER THAN DESIRED. THAT ACTION (ROLLING VERT SPD WHEEL TO REGAIN SPD) CAUSED ALT CAPTURE FUNCTION OF AUTOPLT TO DISARM. THIS RESULTED IN A RAPID DSCNT BELOW ASSIGNED ALT (OF 250 FT). BOTH FO AND SO CALLED OUT DEV. AUTOPLT THEN DISCONNECTED, AND ACFT MANUALLY FLOWN BACK TO ASSIGNED ALT. CAUSAL EVENT: 1) TURB, 2) ATC ASSIGNED ALT 1000 FT BELOW MSA FOR AREA, 3) IMPROPER USE BY PF OF FGS. 4) FIXATION ON LOW AIRSPD, RESULTING IN #3 ABOVE. CORRECTIVE ACTION: 1) PROPER USE OF FGS, ESPECIALLY IN TURB.
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.