Bombardier Learjet Undifferentiated or Other Model
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 100; Flight Crew Total 7000; Flight Crew Type 1200
Inflight Event / Encounter Wake Vortex Encounter
Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action
Procedure; Environment - Non Weather Related
My crewmate and I were conducting an IFR flight to TUL. We were given vectors and instructions from ATC (Center) to expedite our descent 'all the way down' from our cruising altitude of FL430 to FL240. I complied with the heading assignment and began a descent at approximately 2;000 feet per minute. Approximately two minutes later; ATC asked if we could increase our descent rate; [the First Officer] replied that we could; and they again asked us to expedite our descent. I subsequently increased our rate of descent to 4;000-4;500 feet per minute. As we descended through approximately FL340 we entered IMC conditions. [While] descending through approximately FL280; we momentarily encountered severe turbulence - we both were strained hard against our shoulder harnesses and seat belts; I heard the contents of the cabin being lifted and dropping back down; the autopilot disconnected; and the airplane's pitch and roll attitude changed very abruptly. At that time I took manual control of the flight controls and slowed our rate of descent and airspeed as [the FO] and I both tried to assess what had happened. Immediately thereafter I saw contrails from another aircraft above us and to our left; and realized that we had just flown through that aircraft's wake. After a quick assessment and communication with [the FO]; I re-engaged the autopilot and we continued our descent as assigned. [The FO] notified ATC that we had just been vectored through wake turbulence. A few minutes later; he notified ATC again; and informed them that we had encountered severe turbulence as a result. ATC asked if there were any injuries or damage to the airplane; [the FO] replied 'not that we know of'; and we were handed off to the next ATC controller. The flight continued to TUL without further incident.
Learjet Captain reported encountering severe wake turbulence descending through FL280.