Gulfstream 400 flight crew reported the loss and recovery of the autopilot and multiple systems duri...

Attributes
ACN	1448770
Time
Date	201705
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Gulfstream IV / G350 / G450
Operating Under FAR Part	Part 91
Flight Phase	Initial Approach
Route In Use	Vectors
Flight Plan	IFR
Component
Aircraft Component	Flight Director
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument
Experience	Flight Crew Last 90 Days 100 Flight Crew Total 10750 Flight Crew Type 2000
Person 2
Function	Captain Pilot Flying
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 50 Flight Crew Total 7200 Flight Crew Type 4000
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Altitude Excursion From Assigned Altitude Inflight Event / Encounter Weather / Turbulence

Narrative:

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.

Original NASA ASRS Text

Title: Gulfstream 400 flight crew reported the loss and recovery of the autopilot and multiple systems during moderate turbulence.

Narrative: 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.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.