Gulfstream G650 captain reported that rudder fail cas message followed by dutch roll required a dive...

Attributes
ACN	1689249
Time
Date	201910
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZZ.ARTCC
State Reference	FO
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Gulfstream G650
Operating Under FAR Part	Part 135
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Rudder Control System
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine Flight Crew Instrument Flight Crew Flight Instructor
Experience	Flight Crew Last 90 Days 30 Flight Crew Total 18200 Flight Crew Type 550
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural Published Material / Policy

Narrative:

Rudder fail cas message followed by dutch roll induced by light turbulence. Unable to maintain altitude or airway. Initially [requested special handling] as dutch roll increased in intensity. Requested block altitude initially; but ATC did not understand this request. Requested lower altitude and descended to FL301. Was able to stabilize the dutch roll and reconnect autopilot. Followed QRH procedure; but rudder remained completely failed including trim function; discussed options for landing airport and diverted to ZZZZ due to favorable wind conditions and weather. Completed safe landing at ZZZZ about 1:40 after initial event. Flight control computers were operational hydraulics were all operational remote electronic units 15 and 16 were both failed along with rudder lvdt disconnect.

Original NASA ASRS Text

Title: Gulfstream G650 Captain reported that Rudder Fail CAS message followed by Dutch Roll required a diversion to a suitable airport.

Narrative: RUDDER FAIL CAS message followed by dutch roll induced by light turbulence. Unable to maintain altitude or airway. Initially [requested special handling] as dutch roll increased in intensity. Requested block altitude initially; but ATC did not understand this request. Requested lower altitude and descended to FL301. Was able to stabilize the dutch roll and reconnect autopilot. Followed QRH procedure; but rudder remained completely failed including trim function; discussed options for landing airport and diverted to ZZZZ due to favorable wind conditions and weather. Completed safe landing at ZZZZ about 1:40 after initial event. Flight control computers were operational hydraulics were all operational Remote Electronic Units 15 and 16 were both failed along with Rudder LVDT Disconnect.

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.

Gulfstream G650 captain reported that rudder fail cas message followed by dutch roll required a diversion to a suitable airport.