Date: 201507
Local time of day: 0601-1200
Location: IAH.Airport, TX
Flight conditions: VMC
Light: Daylight
Aircraft: A320
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class E I90
ATC / advisory: TRACON I90
Second aircraft: B777 Undifferentiated or Other Model
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Second reporter function: Pilot Flying; Captain
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Wake Vortex Encounter; Inflight Event / Encounter Loss Of Aircraft Control
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Took Evasive Action; Flight Crew Regained Aircraft Control
Contributing factors: Environment - Non Weather Related; Procedure
Primary problem: Ambiguous

Narrative: I was the Pilot Monitoring to IAH. During our descent to IAH; we were vectored east off the MSCOT4 arrival into IAH for traffic separation. Houston Approach advised us to expect the DRLLR4 arrival now and also advised we would be following a heavy B777 which was following a Super A380. We were given direct to MPORT and cleared to descend via DRLLR4 after MPORT. We were assigned 280 KTS and were told to expect 250 KTS after MPORT. TCAS display had target at about 8 NM precisely on arrival ND green line in front of us. I looked at our wind and noticed calm winds at FL180. I then stated something to the effect that this wasn't going to be good for wake turbulence. Somewhere between MPORT and DRLLR around 15000 FT MSL and prepared for an encounter; we hit the worst wake turbulence I have ever experienced! With autopilot on in NAV and DES mode the aircraft rolled toward 35 degrees left very quickly. At 30 degrees AOB (Angle of Bank); without thinking; I immediately turned off the autopilot and thought I said I have the controls (not sure) and rolled the aircraft back towards wings level. We then got a 'DUAL INPUT' call and Captain stated he had the controls. We leveled off and called Houston Approach with PIREP. Approach immediately assisted us with vectoring us off course and had us level off at 14000 FT MSL. The aircraft behind us also quickly complained about wake turbulence very soon after our encounter. After additional separation from the Heavys; Approach cleared us to descend and we received a different runway assignment to avoid additional encounters.I called Houston Approach and asked that they review the tapes and see if there were and separation/spacing issues and suggested they save the tape for data collection on significant wake turbulence encounters. During our conversation I learned that we trailed the Heavy 777 by 6 miles when we entered its wake. The precision of the GPS and RNAV arrivals/departures combined with standard 3 degree descent profiles are now creating a greater risk of wake turbulence encounters. Add to that a light wind summer day aloft and we have the formula for a serious incident.I would also like for the [company] to review our data for collection and training. Our flight profile could be used for a [training] event and I believe my reaction could have made the situation worse if I hadn't had a very similar wake turbulence episode with 'Dual Input' as the pilot flying on takeoff. During that event I had proper full stick right during the recovery and the IOE Captain reacted like I just did but didn't stop his input when 'Dual Input' was heard and we rolled all the way over to 35 degrees to the other side before we recovered. Having flown the A320 for over 13 years; not knowing what the other pilot is doing with the stick input can be a serious deficiency when attempting unusual attitude recovery. We need to re-emphasize unusual attitude recovery with auto-pilot on and wake encounters.


Second narrative: On the arrival into IAH (DRILLR RNAV ARR) we were advised by ATC that we were following an A-380 heavy. Descending thru 15;000 feet A/P engaged; the aircraft entered into slow progressive 35 degree left bank. I disengaged the A/P and flew the airplane manually. Advised ATC what had happen and we were given a different altitude and heading; re engaged the A/P continued on the arrival. Rest of flight was uneventful.


Synopsis: A320 flight crew reported encountering severe wake turbulence 6 miles in trail of a B777 on arrival into IAH.