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B777 first officer reported the aircraft began a steep climb and speed quickly rolled back to the amber band during an encounter with a jet stream at FL310.
| Attributes | |
| ACN | 1408903 |
| Time | |
| Date | 201612 |
| Local Time Of Day | 1201-1800 |
| Place | |
| Locale Reference | CZQX.ARTCC |
| State Reference | NF |
| Aircraft 1 | |
| Make Model Name | B777 Undifferentiated or Other Model |
| Flight Phase | Cruise |
| Flight Plan | IFR |
| Person 1 | |
| Function | First Officer Pilot Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Experience | Flight Crew Total 13000 |
| Events | |
| Anomaly | Deviation - Speed All Types Inflight Event / Encounter Weather / Turbulence |
Narrative:
Cruising at FL280 at mach .82 in gander airspace under radar contact. Requested a climb to FL360 to avoid an anticipated bumpy ride at current fl. Gander ATC cleared us to climb and a climb was initiated to FL360 using VNAV. At approximately FL310 the aircraft began to climb at an increasingly accelerated rate and the airspeed began to roll back very quickly. Maximum power was applied and we pushed the nose over using vertical speed with the auto pilot. Maximum altitude attained was approximately 34;500 feet and we began to descend to regain airspeed. The rate of climb was over 5000 fpm; the attitude was approximately 10 degrees; and the airspeed rolled back to below the minimum maneuvering speed; into the amber band below the 'foot'. ATC was advised and re-cleared us to level off at FL340. The speed remained in the amber band for perhaps 10 to 15 seconds before the speed slowly recovered. At no time did the stick shaker activate nor was any buffeting felt.we believe that this incident occurred due to encountering a very strong vertical jetstream shear. In retrospect; it might have more prudent to disconnect the autopilot to achieve a more rapid airspeed recovery.
Original NASA ASRS Text
Title: B777 First Officer reported the aircraft began a steep climb and speed quickly rolled back to the amber band during an encounter with a jet stream at FL310.
Narrative: Cruising at FL280 at Mach .82 in Gander Airspace under radar contact. Requested a climb to FL360 to avoid an anticipated bumpy ride at current FL. Gander ATC cleared us to climb and a climb was initiated to FL360 using VNAV. At approximately FL310 the aircraft began to climb at an increasingly accelerated rate and the airspeed began to roll back very quickly. Maximum power was applied and we pushed the nose over using vertical speed with the auto pilot. Maximum altitude attained was approximately 34;500 feet and we began to descend to regain airspeed. The rate of climb was over 5000 fpm; the attitude was approximately 10 degrees; and the airspeed rolled back to below the minimum maneuvering speed; into the amber band below the 'foot'. ATC was advised and re-cleared us to level off at FL340. The speed remained in the amber band for perhaps 10 to 15 seconds before the speed slowly recovered. At no time did the stick shaker activate nor was any buffeting felt.We believe that this incident occurred due to encountering a very strong vertical jetstream shear. In retrospect; it might have more prudent to disconnect the autopilot to achieve a more rapid airspeed recovery.
Data retrieved from NASA's ASRS site 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.