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B747-400 first officer reported lateral and altitude deviations due to moderate to severe turbulence.
| Attributes | |
| ACN | 1588304 |
| Time | |
| Date | 201810 |
| Environment | |
| Flight Conditions | IMC |
| Aircraft 1 | |
| Make Model Name | B747-400 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Cruise |
| Flight Plan | IFR |
| Person 1 | |
| Function | First Officer Pilot Flying |
| Events | |
| Anomaly | Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Deviation - Track / Heading All Types Inflight Event / Encounter Weather / Turbulence |
Narrative:
At FL330 we encountered heavy moderate to severe turbulence with strong up drafts and down drafts for about two to three minutes. This caused the autothrottles to disconnect; as well as the pitch and lateral modes [of the autopilot].the aircraft pitched up and before it went into the amber region the shaker activated for a split second. I disconnected the autopilot to bring the aircraft slowly to wings level; lowered the deck angle; and got it out of the amber band.during this time I reached for the con ignition to avoid a high altitude flame out.after lowering the nose and wings level I asked the other first officer (first officer) (who had just got on the left seat from giving the ca (captain) a break) to recycle the FD's and a/T. After this; I re-engaged LNAV; VNAV and autopilot.after dealing with all of this we talked to ATC to advise of the altitude and lateral deviations due to the turbulence. We were in IMC conditions but our radar was not showing any sign of buildups; storms; or weather in front of us. I recovered the aircraft to the best of my abilities along with the other first officer and informed the ca of what had happened. Upon landing a logbook entry was made and maintenance was made aware of the event.
Original NASA ASRS Text
Title: B747-400 First Officer reported lateral and altitude deviations due to moderate to severe turbulence.
Narrative: At FL330 we encountered heavy moderate to severe turbulence with strong up drafts and down drafts for about two to three minutes. This caused the autothrottles to disconnect; as well as the pitch and lateral modes [of the autopilot].The aircraft pitched up and before it went into the amber region the shaker activated for a split second. I disconnected the autopilot to bring the aircraft slowly to wings level; lowered the deck angle; and got it out of the amber band.During this time I reached for the CON Ignition to avoid a high altitude flame out.After lowering the nose and wings level I asked the other FO (First Officer) (who had just got on the left seat from giving the CA (Captain) a break) to recycle the FD's and A/T. After this; I re-engaged LNAV; VNAV and autopilot.After dealing with all of this we talked to ATC to advise of the altitude and lateral deviations due to the turbulence. We were in IMC conditions but our radar was not showing any sign of buildups; storms; or weather in front of us. I recovered the aircraft to the best of my abilities along with the other FO and informed the CA of what had happened. Upon landing a logbook entry was made and Maintenance was made aware of the 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.