MD-11
Flight Crew Air Transport Pilot (ATP)
Inflight Event / Encounter Wake Vortex Encounter
Flight Crew Took Evasive Action
Environment - Non Weather Related
In cruise at FL380; 37nm northeast of TUNTO (on A590) we passed below an opposite direction B-747 at FL390. Shortly after passing; we encountered wake turbulence of a moderate degree. The airplane shuddered and then rapidly rolled approximately 20 degrees right. The autopilot commanded a left roll to counteract; but then kicked off. The Captain assumed control and steered us away from the wake. There was no altitude deviation or loss of separation. Dispatch; Maintenance Control and ATC all notified of event after we returned on course. AML entry was made as a precaution; even though no limitation exceedence of any kind was observed. [The cause was the ] 1;000 foot RVSM separation and the direct tailwind that washed the wake directly over us.
Opposite direction B-747 1;000 feet above us created wake turbulence that caused moderate turbulance and our aircraft to roll 15-20 degrees to the right. The autopilot then began to correct back to level when it disconnected causing no more than a 50 foot gain or loss of altitude. The event lasted 15-30 seconds before re-engaging the autopilot and entering smooth air.We had crossed under several other aircraft prior to this on our route and had not even a nibble of turbulence however; in this location the winds aloft were precisely on our tail which allowed the wake to drift down directly into our path at full strength.Also; we did reference the 'Severe Turbulence and or Heavy Rain Ingestion' QRH procedure.When observing winds aloft that are either calm or directly along our track[;] requesting a Lateral Offset as I did in this case after the fact[;] would reduce the chance of a like encounter.
MD-11 flight crew reported encountering wake turbulence that resulted in a 'rapid roll' from opposite direction B747 1;000 ft above their altitude of FL380.