Falcon 2000
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 65; Flight Crew Total 6650; Flight Crew Type 355
Inflight Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Wake Vortex Encounter
Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Regained Aircraft Control
Environment - Non Weather Related; Procedure
While descending via the CHINS4 arrival into BFI (Seattle/King County Boeing Field); on the segment between 'HUMPP' and 'AUBRN'; passing approximately 14;500 ft. MSL at 250 kts. IAS; I encountered wake turbulence. Temporary loss of control was experienced as the aircraft rolled right; back left; and strongly back right again - with the final bank angle in the roll estimated to be beyond 30 but not more than 50 degrees wing down to the right before I could fully react. During the course of the roll and recovery; automation (including autopilot and auto throttle) was disengaged; and at no time did the EGPWS 'BANK ANGLE' warning sound. I stopped the roll and regained controlled flight with full and smooth application of left aileron; while adding power and climbing out of the perceived vortex. Once clear; automation was restored; the event briefed amongst the crew; and I instructed the PNF (Pilot not Flying) to radio Seattle Approach indicating we had 'encountered wake turbulence' and that 'we were attempting to re-establish on the arrival'. The Approach Controller acknowledged the transmission and advised we were following a Boeing 737-900 series sequenced for SEA (Seattle). From there; a normal descent and approach was conducted to the destination airport. No aircraft faults/failures/malfunctions/warnings; nor exceedances were experienced at any time before; during; or after the event. I was aware of the altitude and spacing regarding the traffic ahead on the arrival; with use of TCAS indications and relative altitude; as well situational awareness provided by our aircraft's INAV display. Spacing and distance appeared more than adequate considering the flight conditions; as the preceding aircraft was consistently indicating around 2;500 ft. below our level and well ahead on the arrival. At no time were we given advisories from ATC in regards to traffic ahead; nor caution on wake turbulence.This event was truly unexpected; however; I must credit flight training providers with modeling extremely accurate wake turbulence simulation scenarios that helped me to quickly identify; and recover properly from this real life upset. Experiencing this is a reminder that wake turbulence can be encountered during a descent profile - especially on an RNAV arrival with 'at-or-above/below' vertical crossing restrictions that could result in brief level offs at slower airspeeds which could lead to preceding aircraft generating stronger than expected vortices.
Falcon 2000 Captain reported momentary loss of control after encountering wake turbulence on approach to BFI airport.