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MD11 flight crew encountered extreme turbulence in cruise.
| Attributes | |
| ACN | 1743803 |
| Time | |
| Date | 202005 |
| Local Time Of Day | 0601-1200 |
| Place | |
| Locale Reference | ZZZ.ARTCC |
| State Reference | FO |
| Environment | |
| Flight Conditions | IMC |
| Aircraft 1 | |
| Make Model Name | MD-11 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Cruise |
| Route In Use | Oceanic |
| Flight Plan | IFR |
| Person 1 | |
| Function | Captain Pilot Not Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Person 2 | |
| Function | Pilot Flying First Officer |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Events | |
| Anomaly | Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Inflight Event / Encounter Weather / Turbulence |
Narrative:
At approximately 100 miles west of zzzzz at FL310 ZZZZ radio descended us to FL300 due to traffic. At approximately 50 miles west of zzzzz we encountered extreme wind shear with gains/losses of 25-30kts and gains/losses of 500 feet in altitude. The winds were about 270/125. The autopilot disconnected twice with multiple stick shaker activations; (3 or 4 times); accompanied with tail-wind shear alert displayed on captains pfd (primary flight display). At one point the airspeed was 5kts about the foot with maximum power selected and we were still unable to maintain altitude. I advised that we were unable to maintain our altitude and that we were descending and requested a block altitude of FL270-280. This was approved by ZZZZ radio. The aircraft was under control and able to maintain altitude at FL280 with the spot winds of 270/65 in continuous moderate turbulence. This lasted for about another 5-10 minutes. We remained at FL280 until climbing at ZZZZZ1 to FL310 and talking to ZZZ radio. The first officer did a very good job of controlling the 'attitude' of the aircraft throughout the entire event.
Original NASA ASRS Text
Title: MD11 flight crew encountered extreme turbulence in cruise.
Narrative: At approximately 100 miles West of ZZZZZ at FL310 ZZZZ Radio descended us to FL300 due to traffic. At approximately 50 miles West of ZZZZZ we encountered extreme wind shear with gains/losses of 25-30kts and gains/losses of 500 feet in altitude. The winds were about 270/125. The autopilot disconnected twice with multiple stick shaker activations; (3 or 4 times); accompanied with tail-wind shear alert displayed on Captains PFD (Primary Flight Display). At one point the airspeed was 5kts about the foot with MAX Power selected and we were still unable to maintain altitude. I advised that we were unable to maintain our altitude and that we were descending and requested a block altitude of FL270-280. This was approved by ZZZZ Radio. The aircraft was under control and able to maintain altitude at FL280 with the spot winds of 270/65 in continuous moderate turbulence. This lasted for about another 5-10 minutes. We remained at FL280 until climbing at ZZZZZ1 to FL310 and talking to ZZZ Radio. The First Officer did a very good job of controlling the 'attitude' of the aircraft throughout the entire event.
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.