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B777 flight crew encounters moderate to severe turbulence while en route. Airspeed varied 30 KTS above maximum speed red line to below stick shaker speed.
| Attributes | |
| ACN | 688413 |
| Time | |
| Date | 200602 |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : czqx.artcc |
| State Reference | NF |
| Altitude | msl single value : 36000 |
| Aircraft 1 | |
| Controlling Facilities | artcc : czqx.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B777-200 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Experience | flight time last 90 days : 210 flight time total : 18000 flight time type : 500 |
| ASRS Report | 688413 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Events | |
| Anomaly | inflight encounter : turbulence inflight encounter : weather |
| Independent Detector | other flight crewa other flight crewb |
| Resolutory Action | none taken : anomaly accepted |
| Supplementary | |
| Problem Areas | Weather Environmental Factor |
| Primary Problem | Weather |
Narrative:
Received SIGMET regarding: clear air turbulence from dispatch with a line that crossed our path approximately 200 NM east. Advised flight attendants of the need to put everything away and to be seated and that they had about 20 mins until turbulence. Only 1 aircraft ahead of us to give us a report; but that was enough. The aircraft was well prepared for the encounter and it was severe wind changes in velocity of up to 100 KTS in a less than 10 NM space and changes in direction of up to 120 degrees. Airspeed was out of control; it would fluctuate from 30 KTS into the red to stick shaker in seconds. Pitch limit indicators were in view most of the time. The event lasted approximately 40 mins of heavy; moderate with long periods of severe.
Original NASA ASRS Text
Title: B777 FLT CREW ENCOUNTERS MODERATE TO SEVERE TURB WHILE ENRTE. AIRSPD VARIED 30 KTS ABOVE MAX SPD RED LINE TO BELOW STICK SHAKER SPD.
Narrative: RECEIVED SIGMET REGARDING: CLR AIR TURB FROM DISPATCH WITH A LINE THAT CROSSED OUR PATH APPROX 200 NM E. ADVISED FLT ATTENDANTS OF THE NEED TO PUT EVERYTHING AWAY AND TO BE SEATED AND THAT THEY HAD ABOUT 20 MINS UNTIL TURB. ONLY 1 ACFT AHEAD OF US TO GIVE US A RPT; BUT THAT WAS ENOUGH. THE ACFT WAS WELL PREPARED FOR THE ENCOUNTER AND IT WAS SEVERE WIND CHANGES IN VELOCITY OF UP TO 100 KTS IN A LESS THAN 10 NM SPACE AND CHANGES IN DIRECTION OF UP TO 120 DEGS. AIRSPD WAS OUT OF CTL; IT WOULD FLUCTUATE FROM 30 KTS INTO THE RED TO STICK SHAKER IN SECONDS. PITCH LIMIT INDICATORS WERE IN VIEW MOST OF THE TIME. THE EVENT LASTED APPROX 40 MINS OF HVY; MODERATE WITH LONG PERIODS OF SEVERE.
Data retrieved from NASA's ASRS site as of January 2009 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.