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A dhc-8 commuter encounters wake turbulence from a B777 that was being vectored onto final ahead of the flight.
| Attributes | |
| ACN | 548184 |
| Time | |
| Date | 200204 |
| Day | Sat |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : sea.airport |
| State Reference | WA |
| Altitude | msl single value : 3000 |
| Environment | |
| Flight Conditions | IMC |
| Weather Elements | Turbulence |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : s46.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | Dash 8-200 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | ils localizer & glide slope : 34l other |
| Flight Phase | descent : approach |
| Route In Use | approach : instrument precision |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | tower : sea.tower |
| Operator | common carrier : air carrier |
| Make Model Name | B777 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | ils localizer & glide slope : 34l |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : commercial pilot : atp pilot : cfi pilot : flight engineer pilot : instrument pilot : multi engine |
| Experience | flight time last 90 days : 78 flight time total : 4207 flight time type : 2178 |
| ASRS Report | 548184 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Events | |
| Anomaly | inflight encounter : wake turbulence |
| Independent Detector | other flight crewa other flight crewb |
| Resolutory Action | controller : issued advisory flight crew : regained aircraft control flight crew : exited adverse environment none taken : unable |
| Miss Distance | horizontal : 42000 |
| Supplementary | |
| Problem Areas | Environmental Factor ATC Human Performance Flight Crew Human Performance |
| Primary Problem | Environmental Factor |
Narrative:
On localizer, level at 3000 ft MSL, 7NM behind B777 that was descending over and in front of my airplane. Encountered wake turbulence, airplane rolled 60 degrees to the right before I was able to stop the roll. Stopped roll only after added power, full opposite aileron had no effect until added power. Callback conversation with reporter revealed the following information: reporter stated they were in solid IMC conditions when the aircraft rolled approximately 60 degrees. He said he applied power and came very close to making a complete roll but the added power brought the aircraft back under control. He stated they were extended on downwind to about 16 miles then turned onto final. The controller advised he was vectoring a B777 on to final 7 miles in front of them and to caution wake turbulence. In talking to the tower supervisor after landing, he was told there is no vertical criteria for wake turbulence if the no less than specified minimum distance is met.
Original NASA ASRS Text
Title: A DHC-8 COMMUTER ENCOUNTERS WAKE TURB FROM A B777 THAT WAS BEING VECTORED ONTO FINAL AHEAD OF THE FLT.
Narrative: ON LOCALIZER, LEVEL AT 3000 FT MSL, 7NM BEHIND B777 THAT WAS DESCENDING OVER AND IN FRONT OF MY AIRPLANE. ENCOUNTERED WAKE TURB, AIRPLANE ROLLED 60 DEGS TO THE RIGHT BEFORE I WAS ABLE TO STOP THE ROLL. STOPPED ROLL ONLY AFTER ADDED POWER, FULL OPPOSITE AILERON HAD NO EFFECT UNTIL ADDED POWER. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THEY WERE IN SOLID IMC CONDITIONS WHEN THE ACFT ROLLED APPROX 60 DEGS. HE SAID HE APPLIED POWER AND CAME VERY CLOSE TO MAKING A COMPLETE ROLL BUT THE ADDED POWER BROUGHT THE ACFT BACK UNDER CTL. HE STATED THEY WERE EXTENDED ON DOWNWIND TO ABOUT 16 MILES THEN TURNED ONTO FINAL. THE CTLR ADVISED HE WAS VECTORING A B777 ON TO FINAL 7 MILES IN FRONT OF THEM AND TO CAUTION WAKE TURB. IN TALKING TO THE TWR SUPVR AFTER LNDG, HE WAS TOLD THERE IS NO VERTICAL CRITERIA FOR WAKE TURB IF THE NO LESS THAN SPECIFIED MINIMUM DISTANCE IS MET.
Data retrieved from NASA's ASRS site as of July 2007 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.