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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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Medium large transport altitude excursion due to severe up and downdrafts caused by thunderstorm turbulence causing the aircraft autoplt to disengage, including the automatic throttle control.
| Attributes | |
| ACN | 375645 |
| Time | |
| Date | 199707 |
| Day | Sat |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : ocs |
| State Reference | WY |
| Altitude | msl bound lower : 33800 msl bound upper : 35200 |
| Environment | |
| Flight Conditions | IMC |
| Light | Dusk |
| Aircraft 1 | |
| Controlling Facilities | artcc : zlc |
| Operator | common carrier : air carrier |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : flight engineer pilot : instrument pilot : commercial |
| Experience | flight time last 90 days : 150 flight time total : 10000 flight time type : 150 |
| ASRS Report | 375645 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 120 flight time total : 22400 flight time type : 1600 |
| ASRS Report | 374740 |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude inflight encounter : weather non adherence : clearance other anomaly other |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : exited adverse environment flight crew : returned to intended course or assigned course |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Weather |
| Air Traffic Incident | Pilot Deviation |
Narrative:
Cruising at FL350. We had deviated around numerous thunderstorms. Captain knocked over food tray resting on jump seat. The ensuing clean-up and discussion with flight attendant diverted my attention from flying the aircraft and going around buildups. Encountered moderate turbulence and began turn away from cell painting on WX radar screen. Flight attendant entered cockpit advising us of medical emergency and at the same time, while in turn, the autoplt and autothrottle system disengaged. Aircraft was in 30 degree bank and 6 degrees nose low. I hand flew back to assigned altitude and engaged automatic system once out of the turbulence. We advised ARTCC of altitude deviation (approximately 1200 ft). More diligent use of WX radar and attention to flying the aircraft would have prevented flying into the turbulence and subsequent altitude deviation.
Original NASA ASRS Text
Title: MLG ALT EXCURSION DUE TO SEVERE UP AND DOWNDRAFTS CAUSED BY TSTM TURB CAUSING THE ACFT AUTOPLT TO DISENGAGE, INCLUDING THE AUTO THROTTLE CTL.
Narrative: CRUISING AT FL350. WE HAD DEVIATED AROUND NUMEROUS TSTMS. CAPT KNOCKED OVER FOOD TRAY RESTING ON JUMP SEAT. THE ENSUING CLEAN-UP AND DISCUSSION WITH FLT ATTENDANT DIVERTED MY ATTN FROM FLYING THE ACFT AND GOING AROUND BUILDUPS. ENCOUNTERED MODERATE TURB AND BEGAN TURN AWAY FROM CELL PAINTING ON WX RADAR SCREEN. FLT ATTENDANT ENTERED COCKPIT ADVISING US OF MEDICAL EMER AND AT THE SAME TIME, WHILE IN TURN, THE AUTOPLT AND AUTOTHROTTLE SYS DISENGAGED. ACFT WAS IN 30 DEG BANK AND 6 DEGS NOSE LOW. I HAND FLEW BACK TO ASSIGNED ALT AND ENGAGED AUTO SYS ONCE OUT OF THE TURB. WE ADVISED ARTCC OF ALTDEV (APPROX 1200 FT). MORE DILIGENT USE OF WX RADAR AND ATTN TO FLYING THE ACFT WOULD HAVE PREVENTED FLYING INTO THE TURB AND SUBSEQUENT ALTDEV.
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.