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An air carrier MD80 flight crew entered a small thunderstorm at night and suffered severe turbulence. The thunderstorm did not show on the radar. No injuries.
| Attributes | |
| ACN | 402002 |
| Time | |
| Date | 199805 |
| Day | Fri |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : lit |
| State Reference | AR |
| Altitude | msl bound lower : 33000 msl bound upper : 33600 |
| Environment | |
| Flight Conditions | Mixed |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | artcc : zme |
| Operator | common carrier : air carrier |
| Make Model Name | MD-80 Super 80 |
| Navigation In Use | Other |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| ASRS Report | 402002 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude inflight encounter : weather non adherence : clearance other anomaly other anomaly other |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : returned to intended course or assigned course flight crew : regained aircraft control |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Weather |
| Air Traffic Incident | other |
Narrative:
In cruise, autoplt on, at FL330, seat belt sign off, in clear air with ground visible, but partially reduced forward visibility. Radar on 80 mi scale tilted down to show ground return at fringe (70 mi or so) flew into a towering cumulus cell that was not painting on radar. Cell was small, 2-3 mi across. Encountered moderate to severe turbulence which lasted 30-40 seconds. No injuries in cabin to passenger or crew. Mach number instantaneously went from .76 to .825 uncommanded roll 35 degrees. Altitude gain of 600 ft, no traffic conflict. Copilot flying did excellent job regaining control without any noticeable positive or negative acceleration forces (G loading). The absence of a large uncommanded pitch moment I believe helped keep injuries at zero. Flight landed normally at bna. A log entry made to indicate severe turbulence encounter.
Original NASA ASRS Text
Title: AN ACR MD80 FLC ENTERED A SMALL TSTM AT NIGHT AND SUFFERED SEVERE TURB. THE TSTM DID NOT SHOW ON THE RADAR. NO INJURIES.
Narrative: IN CRUISE, AUTOPLT ON, AT FL330, SEAT BELT SIGN OFF, IN CLR AIR WITH GND VISIBLE, BUT PARTIALLY REDUCED FORWARD VISIBILITY. RADAR ON 80 MI SCALE TILTED DOWN TO SHOW GND RETURN AT FRINGE (70 MI OR SO) FLEW INTO A TOWERING CUMULUS CELL THAT WAS NOT PAINTING ON RADAR. CELL WAS SMALL, 2-3 MI ACROSS. ENCOUNTERED MODERATE TO SEVERE TURB WHICH LASTED 30-40 SECONDS. NO INJURIES IN CABIN TO PAX OR CREW. MACH NUMBER INSTANTANEOUSLY WENT FROM .76 TO .825 UNCOMMANDED ROLL 35 DEGS. ALT GAIN OF 600 FT, NO TFC CONFLICT. COPLT FLYING DID EXCELLENT JOB REGAINING CTL WITHOUT ANY NOTICEABLE POSITIVE OR NEGATIVE ACCELERATION FORCES (G LOADING). THE ABSENCE OF A LARGE UNCOMMANDED PITCH MOMENT I BELIEVE HELPED KEEP INJURIES AT ZERO. FLT LANDED NORMALLY AT BNA. A LOG ENTRY MADE TO INDICATE SEVERE TURB ENCOUNTER.
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.