Learjet 60
Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor; Flight Crew Multiengine
Flight Crew Last 90 Days 30; Flight Crew Total 8500; Flight Crew Type 2500
Aircraft Equipment Problem Less Severe; Deviation - Altitude Excursion From Assigned Altitude; Inflight Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Weather / Turbulence
Flight Crew Regained Aircraft Control
Aircraft; Weather
Over the Gulf of Mexico we encountered severe turbulence. Our radar was working on departure but failed at some point prior to the encounter. When we noticed the radar inop; we asked ZJX Center for 10 miles right based on our storm scope and ZJX Center's radar return. Neither were perfect but all that was available. When the turbulence happened we lost approximately 3;300 ft; bank angle at the most extreme was 45 degrees.
Learjet 60 First Officer reported an encounter with severe turbulence at FL400 resulted in an uncommanded 45 degree bank and loss of 3300 ft.