Hawker 800XP flight crew reported encountering wake turbulence at 12;000 ft. in the vicinity of JFK from a B747 that resulted in an altitude excursion.
Synopsis
Hawker 800XP flight crew reported encountering wake turbulence at 12;000 ft. in the vicinity of JFK from a B747 that resulted in an altitude excursion.
Narrative
Shortly after beginning a turn from a 360 heading to 330 heading cruising at 12;000 ft. with the autopilot engaged; the aircraft began to encounter moderate turbulence. Within 10 seconds of encountering this moderate turbulence while in a 30 degree banked left turn; the autopilot suddenly disengaged uncommanded and the airplane rapidly began to bank towards the right. The PIC (Pilot in Command) (PF (Pilot Flying)) called out 'I got the controls' and commanded full left aileron. The airplane continued to increase the right bank until finally stopping at 40 degrees with a slight pitch up. The PIC continued holding full left aileron and the aircraft continued to hold a 40 degree right bank and stated 'I think we have a flight control problem.' Shortly after that within 15 seconds; the aircraft began to roll back to the left. As the aircraft returned to wings level attitude the PIC rolled out the left aileron to command a straight and level attitude. The turbulence had subsided at this time. This was held for a short while until we realized that during the event; we had climbed about 340 ft. The PIC then initiated a descent to return to 12;000. At 12;000 ft.; the PIC then initiated a left turn back to our assigned heading of 330. After observing that the airplane was responding correctly to flight control commands; we turned the autopilot on to test its functionality. The autopilot was able to hold altitude and heading with no abnormalities. During our initial climb out of FRG; I noticed a large aircraft that was flying east out of JFK at an altitude slightly above us while we were flying southeast. ATC turned them north and had them climb then had us climb above that initial altitude and turned us west to cross over their flight path then turned us northwest and cleared us to 12;000. Throughout this maneuvering we remained relatively close to that large aircraft and they remained at higher altitudes then us. That aircraft was a 747. They had flown 500 ft. above where we encountered this environment one minute prior as they were climbing to a higher altitude.Given that we had no flight control problems after recovering from the upset condition; the close proximity of a much larger aircraft; and the nature of the upset our aircraft experienced; this event was directly related to wake turbulence.
Second reporter narrative
We experienced wake turbulence while in VMC cruise at 12000 ft. We departed FRG getting vectors by NY departure with the autopilot engaged. We experienced sudden violent turbulence. The plane began an uncommanded hard right bank and the autopilot disengaged. I attempted to regain control of the plane with full left aileron while the plane maintained a 40 degree right bank. We passed through the turbulence and I was able to regain stable level flight. I told NY Departure of the wake turbulence event. We deviated from our assigned altitude by +300 ft.
NASA callback
Reporter stated both they and ATC were surprised by the wake encounter.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.