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An MD88 following 20 mi behind a B777 encounters wake turbulence resulting in turbulence and a roll of up to 90 degrees before recovery is accomplished.
| Attributes | |
| ACN | 547918 |
| Time | |
| Date | 200205 |
| Day | Sat |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | intersection : macey |
| State Reference | GA |
| Altitude | msl single value : 20000 |
| Environment | |
| Flight Conditions | VMC |
| Weather Elements | Turbulence |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : ztl.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | MD-88 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | descent : intermediate altitude |
| Route In Use | arrival star : macey 2 |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : ztl.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B777 Undifferentiated or Other Model |
| Flight Phase | cruise : level descent : intermediate altitude |
| Route In Use | arrival star : macey 2 |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 200 flight time total : 4000 flight time type : 2400 |
| ASRS Report | 547918 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Events | |
| Anomaly | inflight encounter : wake turbulence other anomaly |
| Independent Detector | other flight crewa |
| Resolutory Action | controller : issued new clearance flight crew : exited adverse environment flight crew : took precautionary avoidance action flight crew : regained aircraft control other |
| Supplementary | |
| Problem Areas | Environmental Factor |
| Primary Problem | Environmental Factor |
Narrative:
20 mi in trail of B777 on macey arrival at FL200, got uncommanded roll 45-90 degrees both right, then left with moderate turbulence. Again at approximately FL180 got roll of 35-45 degrees in both directions. ATC informed us of B777 20 mi ahead. Wind was right crosswind at 35 KTS. Offset upwind rest of arrival with no further incident. Callback conversation with reporter revealed the following information: the autoplt was in use but disconnected automatically with the turbulence encounter. During the hand flown recovery near full control inputs were used. Both aircraft involved were on the macey 2 arrival with a crossing restr of 13000 ft at womac intersection. There was no other reported turbulence reported in the area.
Original NASA ASRS Text
Title: AN MD88 FOLLOWING 20 MI BEHIND A B777 ENCOUNTERS WAKE TURB RESULTING IN TURB AND A ROLL OF UP TO 90 DEGS BEFORE RECOVERY IS ACCOMPLISHED.
Narrative: 20 MI IN TRAIL OF B777 ON MACEY ARR AT FL200, GOT UNCOMMANDED ROLL 45-90 DEGS BOTH R, THEN L WITH MODERATE TURB. AGAIN AT APPROX FL180 GOT ROLL OF 35-45 DEGS IN BOTH DIRECTIONS. ATC INFORMED US OF B777 20 MI AHEAD. WIND WAS R XWIND AT 35 KTS. OFFSET UPWIND REST OF ARR WITH NO FURTHER INCIDENT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE AUTOPLT WAS IN USE BUT DISCONNECTED AUTOMATICALLY WITH THE TURB ENCOUNTER. DURING THE HAND FLOWN RECOVERY NEAR FULL CTL INPUTS WERE USED. BOTH ACFT INVOLVED WERE ON THE MACEY 2 ARR WITH A XING RESTR OF 13000 FT AT WOMAC INTXN. THERE WAS NO OTHER RPTED TURB RPTED IN THE AREA.
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.