B747-400
Flight Crew Air Transport Pilot (ATP)
Deviation - Altitude Excursion From Assigned Altitude; Deviation - Speed All Types; Inflight Event / Encounter Weather / Turbulence; Inflight Event / Encounter Loss Of Aircraft Control
Flight Crew Returned To Clearance; Flight Crew Regained Aircraft Control
Weather
Cruising 35;000 experienced moderate turbulence; of such intensity also accompanied by extreme wave action that the acft deviated from assigned flight level by 800 FT above FL350. The Captain disconnected the autopilot to avert exceeding structural limits. The acft also exceeded Mmo momentarily. The event lasted approximately 40 to 60 seconds. The Captain was able to return to altitude. The remainder of the flight was uneventful.
B747 First Officer describes a turbulence encounter with wave action; that results in the aircraft climbing 800 FT above FL350 while exceeding Mmo. The event occurred several hundred miles east of Japan over the Pacific Ocean.