Date: 201210
Local time of day: 1801-2400
Location: LAS.Airport, NV
Flight conditions: VMC
Aircraft: A319
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class B LAS
ATC / advisory: TRACON L30; Tower LAS
Second aircraft: B777 Undifferentiated or Other Model
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Anomaly: ATC Issue All Types; Inflight Event / Encounter Wake Vortex Encounter
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Executed Go Around / Missed Approach; Flight Crew Took Evasive Action
Contributing factors: Human Factors; Environment - Non Weather Related
Primary problem: Ambiguous

Narrative: This was a wake turbulence encounter event due to very close ATC vector to join a visual approach behind a 'Heavy' Aircraft. We were on the Tyssn3 arrival with a vector to cross PRINO at 8;000 and 210 KTS. All other aircraft were receiving approach clearance to join the 25L glideslope at PRINO (GS intercept). Over PRINO we were cleared to descend to 6;500 and that we were number 2 behind a 'Heavy' on downwind. At 6;500 were cleared to slow to 170 KTS. We slowed and called the heavy traffic in sight and runway in sight. We were then cleared for a visual approach to 25L. We configured quickly with full speed brakes and requested 'overtake' info from Tower. Tower advised a 20 KT overtake. We where at CONFIG full approach speed; unable to slow any further. On TCAS our leader traffic was less than 2 miles and less than 500 FT below. I requested 'S' turns for spacing. Tower approved turns to the south with helicopter traffic in the area. I observed a TCAS target to our left (south) and elected not to make the 'S' turn. We requested visual to 25R. I sidestepped and regained 'stable' with the CF to 25R selected in the MCDU. We were above 1;000 FT AGL. We encountered a strong rolling moment to the left. I recovered and recognized a wake turbulence possibility. We encountered a 2nd stronger rolling moment and several strong 'bumps'. I selected TOGA and called 'Go Around FLAPS 1'. The Go Around instructions were runway heading to 4;000 FT. In the climb we recovered to a clean configuration with no further complications. I believe we encountered the wake below 1;000 FT AGL; or around 3;000 FT MSL. We were in compliance with ATC assigned speed in a high traffic volume area. There were several aircraft ahead of us and behind us. Although I recognized we were fast over PRINO I was unable to request slower due to high radio traffic volume. When we crossed PIONS without an approach clearance at 210 we were immediately high and fast. When ATC advised number two behind a heavy on downwind; I should have requested slower. We received slower at 6;500 FT. I called the traffic in sight but should have not accepted the approach clearance while still high and fast with such an impossible separation situation. This approach was impossible. Even if we were able to maintain the approach behind the 'heavy' we absolutely would have been going around because our traffic was on the runway. I had the ND selected on the lowest range and showed our traffic well inside the inner ring (2.5 miles). When cleared for the approach TCAS also showed him 500 FT below us. With a 20 KT overtake we could never have given adequate space for him to land and clear. Low altitude Go Arounds are uncomfortable and upsetting for both passengers and crews. Las Vegas Approach brought us in way too close. The heavy traffic should have been vectored behind us; or we should have been slowed much sooner.




Synopsis: A319 Captain reported wake vortex encounter on arrival to LAS that resulted in a go-around. Reporter stated ATC vector was too tight to be workable.