MD80 FLT CREW ENCOUNTERS WAKE TURB DURING CLB TO ALT FROM PRECEDING B777.

Narrative

WE WERE CLBING FROM FL350 TO FL370. A B777 HAD PREVIOUSLY PASSED US AT FL370. WE WERE ON THE SAME FLT PATH. AT FL365 WE ENCOUNTERED HIS WAKE TURB AND ROLLED ABOUT 30 TO 45 DEGS. THE TOTAL ENCOUNTER WAS ABOUT 15 TO 20 SECONDS LONG WITH AT TIMES STRONG BUFFETING. MY FO HAD TO FIGHT THE CTLS AND THE ROLLING MOMENT TO STAY IN CONTROL. NO INJURIES. REMINDED PAX THAT THIS IS WHY WE ASK THEM TO WEAR THEIR SEATBELTS. THE KEY TO THIS ENCOUNTER -- WE NEVER WOULD HAVE ANTICIPATED THIS BECAUSE THE B777 WAS 12 MILES AHEAD OF US.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT THEY DID NOT EXPECT ANY ENCOUNTER AS THE B777 WAS WELL PAST THEIR POSITION. THE WIND WAS A QUARTERING TAILWIND OF APPROX 50 KTS. THE ACFT WAS ON THE EXACT SAME COURSE AS THE B777 AND APPROX 12 NM PAST THE RPTR'S ACFT PRIOR TO THE CLB BEING INITIATED TO THE NEXT ALT. AS THE CLB WAS INITIATED AT APPROX FL365; THE ACFT BEGAN TO SHUDDER SEVERAL TIMES AND THEN THE ROLL WAS QUITE VIOLENT TO APPROX 45 DEGS; REQUIRING FULL AILERON DEFLECTION TO BRING IT BACK TO FLT LEVEL. RPTR STATED THAT BOTH HE AND FO WERE CAUGHT BY SURPRISE BY THE ENCOUNTER AS THEY ACTUALLY WATCHED THE OTHER ACFT'S DISTANCE ON THE TCAS AND ASSUMED THAT WAS SUFFICIENT.