BAe 125 Series 800
Flight Crew Air Transport Pilot (ATP)
Inflight Event / Encounter Wake Vortex Encounter
Air Traffic Control Issued New Clearance; Flight Crew Took Evasive Action
Environment - Non Weather Related
During the descent on the DELRO2 arrival into IAD; we were assigned a crossing restriction of 250 KTS and 10;000 FT at HYPER Intersection. Passing about 12;000 FT we experienced unusual turbulence; more of a rumble. Around 11;000 FT the aircraft suddenly rolled at least 30 degrees to the left. I disconnected the autopilot and corrected with the flight controls. The pilot not flying contacted ATC and advised them that we would be leveling off and not making the crossing restriction at HYPER. We informed them that we had encountered the wake of another aircraft. ATC advised us that we were 12 miles in trail of a Heavy. Again; approaching 10;600 we experienced another rumble and another roll. The autopilot was off and I was hand flying; so I returned the aircraft to straight and level flight. The pilot not flying requested a turn away from the flight path of the preceding aircraft. We were assigned a 260 heading; and told that we were going to be changed from 19L to 19C to ensure separation with the preceding aircraft. The rest of the flight continued without incident. We checked on the passengers; who were both seated and wearing seat belts at the time of the wake turbulence encounter. Neither were injured and appeared to be ok. Both a visual scan for aircraft and on the TCAS are important ways for ensuring the adequate separation of aircraft. In addition; an awareness of winds aloft are important. It appears that we encountered the wake in spite of having the adequate required ATC separation; but meteorological conditions caused the wake to linger longer than it normally would.
BAE-125-850XP First Officer reported encountering wake vortex in trail of a Heavy on approach to IAD.