Gulfstream IV / G350 / G450
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Flight Crew Last 90 Days 100; Flight Crew Total 10750; Flight Crew Type 2000
Aircraft Equipment Problem Less Severe; Deviation - Altitude Excursion From Assigned Altitude; Inflight Event / Encounter Weather / Turbulence
Aircraft Equipment Problem Dissipated; Flight Crew Returned To Clearance
Aircraft; Weather
We encountered moderate turbulence and subsequent loss of the flight director; auto-throttles; autopilot; and yaw damp as well as electric trim. Additionally; we lost the use of both display controllers; and the flight guidance panel which prevented us from inputting data in the altitude select window; heading window and the speed window. We were unable to select our assigned heading or altitudes for our PFDs; and we could not input any data to perform an ILS approach. The aircraft was being flown on autopilot at the time of the encounter with the moderate turbulence. By the time we realized we had lost the autopilot and electric trim; we had descended 500 ft. below our assigned altitude. We reverted to manual trim; and returned to our assigned altitude. At the same time this was happening; we alerted ATC to our problem and requested priority assistance since we were unsure of the nature of the failures at that time; and were concerned we could possibly experience a total loss of flight instrumentation. After a few minutes; we were able to get all systems back online and advised ATC we were back to normal flight operations. We completed the flight without further incident.This appeared to be a mechanical failure possibly induced by moderate turbulence.
[Report narrative contained no additional information.]
Gulfstream 400 flight crew reported the loss and recovery of the autopilot and multiple systems during moderate turbulence.