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An air carrier medium large transport crew was thrust downward at the base of thunderstorms.
| Attributes | |
| ACN | 271550 |
| Time | |
| Date | 199405 |
| Day | Thu |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : elp |
| State Reference | TX |
| Altitude | msl bound lower : 9800 msl bound upper : 11000 |
| Environment | |
| Flight Conditions | Mixed |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zob |
| Operator | common carrier : air carrier |
| Make Model Name | B737-200 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | cruise other descent other |
| Route In Use | approach : contact approach : visual enroute : direct enroute airway : zab |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 300 flight time total : 9100 flight time type : 1000 |
| ASRS Report | 271550 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : cfi pilot : atp |
| Experience | flight time last 90 days : 180 flight time total : 22000 flight time type : 4000 |
| ASRS Report | 271542 |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude inflight encounter : weather non adherence : clearance other anomaly |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other controllera other flight crewa |
| Resolutory Action | flight crew : regained aircraft control flight crew : returned to intended course or assigned course other |
| Consequence | faa : reviewed incident with flight crew |
| Supplementary | |
| Primary Problem | Weather |
| Air Traffic Incident | other |
Narrative:
An area of thunderstorms were building in the ft. Stockton area. As we descended into el paso, we weaved and dodged our way uneventfully. As we were leveling at 11000 ft, we saw a momentary visual break ahead and saw no rain under a cell which showed some returns (light) but did not look ominous. We entered the bases and requested lower from ZAB, which was denied for MOCA. No sooner out of my mouth and I noticed our altitude of 10700 and descending rapidly. I advised the captain at which time the autoplt disengaged. The captain tried to arrest the descent and was unable to stop it until 9800 ft at which time we climbed back to 11000 ft. After landing we looked back to the east and estimated the tops at 35000 ft. We thought we were clear of the heavy WX, but a growing thunderstorm and downdraft caught us totally off guard. Supplemental information from acn 271542: ZAB advises of SIGMET -- line of thunderstorms 20 mi wide, tops 45000 from south of elp thought north moving northeast. Cleared to deviate left or right of course -- direct elp when able. Cleared from 31000-12000 ft. Picking way through line of thunderstorms, excellent WX radar return -- solid to broken. Leveled at 12000 ft. Descended to 11000 ft because of turbulence to maintain aircraft control. Center advised of wrong altitude. I advised we were in turbulence. After air smoothed out. Leveled at 12000. Aircraft type boeing 737-220.
Original NASA ASRS Text
Title: AN ACR MLG CREW WAS THRUST DOWNWARD AT THE BASE OF TSTMS.
Narrative: AN AREA OF TSTMS WERE BUILDING IN THE FT. STOCKTON AREA. AS WE DSNDED INTO EL PASO, WE WEAVED AND DODGED OUR WAY UNEVENTFULLY. AS WE WERE LEVELING AT 11000 FT, WE SAW A MOMENTARY VISUAL BREAK AHEAD AND SAW NO RAIN UNDER A CELL WHICH SHOWED SOME RETURNS (LIGHT) BUT DID NOT LOOK OMINOUS. WE ENTERED THE BASES AND REQUESTED LOWER FROM ZAB, WHICH WAS DENIED FOR MOCA. NO SOONER OUT OF MY MOUTH AND I NOTICED OUR ALT OF 10700 AND DSNDING RAPIDLY. I ADVISED THE CAPT AT WHICH TIME THE AUTOPLT DISENGAGED. THE CAPT TRIED TO ARREST THE DSCNT AND WAS UNABLE TO STOP IT UNTIL 9800 FT AT WHICH TIME WE CLBED BACK TO 11000 FT. AFTER LNDG WE LOOKED BACK TO THE E AND ESTIMATED THE TOPS AT 35000 FT. WE THOUGHT WE WERE CLR OF THE HVY WX, BUT A GROWING TSTM AND DOWNDRAFT CAUGHT US TOTALLY OFF GUARD. SUPPLEMENTAL INFO FROM ACN 271542: ZAB ADVISES OF SIGMET -- LINE OF TSTMS 20 MI WIDE, TOPS 45000 FROM S OF ELP THOUGHT N MOVING NE. CLRED TO DEVIATE L OR R OF COURSE -- DIRECT ELP WHEN ABLE. CLRED FROM 31000-12000 FT. PICKING WAY THROUGH LINE OF TSTMS, EXCELLENT WX RADAR RETURN -- SOLID TO BROKEN. LEVELED AT 12000 FT. DSNDED TO 11000 FT BECAUSE OF TURB TO MAINTAIN ACFT CTL. CTR ADVISED OF WRONG ALT. I ADVISED WE WERE IN TURB. AFTER AIR SMOOTHED OUT. LEVELED AT 12000. ACFT TYPE BOEING 737-220.
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.