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Moderate to severe turbulence during their approach for landing contributed to a descent below their cleared altitude and an altitude warning from ATC for a B747-400 flight crew.
| Attributes | |
| ACN | 1164641 |
| Time | |
| Date | 201404 |
| Local Time Of Day | 1801-2400 |
| Place | |
| Locale Reference | ANC.Airport |
| State Reference | AK |
| Environment | |
| Flight Conditions | VMC |
| Aircraft 1 | |
| Make Model Name | B747-400 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Initial Approach |
| Route In Use | Vectors |
| Flight Plan | IFR |
| Person 1 | |
| Function | Captain Pilot Not Flying |
| Qualification | Flight Crew Multiengine Flight Crew Instrument Flight Crew Flight Engineer Flight Crew Air Transport Pilot (ATP) |
| Experience | Flight Crew Last 90 Days 150 Flight Crew Total 6000 Flight Crew Type 1600 |
| Events | |
| Anomaly | Deviation - Altitude Overshoot Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Inflight Event / Encounter CFTT / CFIT Inflight Event / Encounter Weather / Turbulence |
Narrative:
During a trans-pacific flight to anc [while] on approach vectors; we were cleared to descend to 1;600 ft in continuous light to moderate turbulence. I believe the heading was 050 to intercept the localizer to [runway] 07R. The first officer was hand flying. I was working the radio; MCP; flaps and FMS selections. Around 2;000 ft we began to go from moderate to severe turbulence. The first officer inadvertently overshot the altitude to about 1;200 ft. I was distracted from instrument monitoring due to MCP and flap selections. The first officer also mentioned loss of airspeed; windshear; of approximately 20 KTS. Approach control drew attention to our altitude as I was about to report the turbulence. The first officer corrected back to 1;600 ft. I also said we had the airport in sight and accepted the visual approach. The turbulence returned to light to moderate and I gave another PIREP. We landed with no further problems. As typical; everything seemed to happen at the same time.
Original NASA ASRS Text
Title: Moderate to severe turbulence during their approach for landing contributed to a descent below their cleared altitude and an altitude warning from ATC for a B747-400 flight crew.
Narrative: During a trans-Pacific flight to ANC [while] on approach vectors; we were cleared to descend to 1;600 FT in continuous light to moderate turbulence. I believe the heading was 050 to intercept the LOC to [Runway] 07R. The First Officer was hand flying. I was working the radio; MCP; flaps and FMS selections. Around 2;000 FT we began to go from moderate to severe turbulence. The First Officer inadvertently overshot the altitude to about 1;200 FT. I was distracted from instrument monitoring due to MCP and flap selections. The First Officer also mentioned loss of airspeed; windshear; of approximately 20 KTS. Approach Control drew attention to our altitude as I was about to report the turbulence. The First Officer corrected back to 1;600 FT. I also said we had the airport in sight and accepted the visual approach. The turbulence returned to light to moderate and I gave another PIREP. We landed with no further problems. As typical; everything seemed to happen at the same time.
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.