Date: 201501
Local time of day: 1201-1800
Location: MEM.Airport, TN
Flight conditions: VMC
Light: Daylight
Aircraft: McDonnell Douglas Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Initial Approach
Airspace: Class B MEM
ATC / advisory: Tower MEM
Second aircraft: B777 Undifferentiated or Other Model
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Second reporter function: Pilot Not Flying; First Officer
Anomaly: ATC Issue All Types; Inflight Event / Encounter Unstabilized Approach; Inflight Event / Encounter Wake Vortex Encounter; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Executed Go Around / Missed Approach
Contributing factors: Environment - Non Weather Related; Procedure; Weather
Primary problem: Procedure

Narrative: While on approach to runway 36L; we were following a B777 by about 6 miles.  The winds on final were 180 at 14 knots while flying down final.  At around 350 feet AGL; the wind shifted to something close to 210 to 220 at 23 knots.  As the winds were shifting I started to notice some wake turbulence.  At around 250 feet AGL; the turbulence was strong enough that I decided to go around.  Our wing rock was over 5 degrees left and right.  We reported the wake turbulence encounter to both Tower and Approach. MEM continues to operate in a North landing configuration while the winds aloft and surface winds are from the south.  While the surface winds are reported as less than a 10 knot tailwind; the winds on final down to 100 feet can be in excess of our limits.  In this case; the wind shifted and increased around 350 to 250 feet AGL which presented us with wake turbulence on final low to the ground.Like it or not; Memphis needs to land into the wind.  This time of the year the winds aloft close to the ground can be a lot stronger than the surface winds which lead to these encounters.


Second narrative: Visual approach; landing 36L. Tailwind and some crosswind on final. On short final at approximately 300 FT AGL we encountered moderate turbulence and an increase in tailwind/crosswind and elected to go around. At approximately 1000 FT AGL we had a left quartering tailwind of 23 knots. At approximately 500 FT AGL wind shifted to mostly crosswind of approximately 13 knots. At approximately 300 FT quartering tailwind picked back up over 20 knots and we encountered turbulence causing the wings to rock. We were behind another heavy aircraft approximately 6 miles in front (maybe a 777). The turbulence started to cause the wings to rock the aircraft also started to go high on glide path. As I was assessing stability parameters of the aircraft during this sudden encounter of turbulence and wind shift effect the Captain elected to go around. We went around before any issues arose and safety was compromised.


Synopsis: Flight crew reported executing a go-around after encountering wake turbulence in trail of a B777 on approach to MEM. Reporter stated ATC should be more aware of wind issues when deciding which approaches and runways should be used.