A G200 first officer discovered that an uncommanded left turn after takeoff was caused by rudder tri...

Attributes
ACN	886260
Time
Date	201004
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZZ.Airport
State Reference	FO
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Gulfstream G200 (IAI 1126 Galaxy)
Operating Under FAR Part	Part 135
Flight Phase	Initial Climb Takeoff
Route In Use	Vectors
Flight Plan	IFR
Component
Aircraft Component	Rudder Trim System
Person 1
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Instrument Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 50 Flight Crew Total 4500 Flight Crew Type 250
Events
Anomaly	Deviation - Procedural Published Material / Policy Deviation - Track / Heading All Types Inflight Event / Encounter Loss Of Aircraft Control

Narrative:

After normal preflight; taxi and take-off roll; with a seventeen knot crosswind; following rotation and lift off the aircraft yawed left in an uncommanded left turn. The flying pilot attempted to return the aircraft to runway heading but was not able to. The aircraft continued in a climbing left turn. As the pilot not at the controls I at first thought the yaw was to maintain runway alignment. When I recognized that was not the case I scanned the panel to determine if an engine had failed or not. During the scan I noted the rudder trim indicated six left. I immediately began to retrim the rudder to zero. With the rudder at zero the aircraft was fully controllable. We had turned through about 180 degrees of heading. Tower told us to return to runway heading so the pilot at the controls continued the left turn to runway heading.

Original NASA ASRS Text

Title: A G200 First Officer discovered that an uncommanded left turn after takeoff was caused by rudder trim set at six degrees left. After the trim was zeroed the flight controls returned to normal and the aircraft returned to course.

Narrative: After normal preflight; taxi and take-off roll; with a seventeen knot crosswind; following rotation and lift off the aircraft yawed left in an uncommanded left turn. The flying pilot attempted to return the aircraft to runway heading but was not able to. The aircraft continued in a climbing left turn. As the pilot not at the controls I at first thought the yaw was to maintain runway alignment. When I recognized that was not the case I scanned the panel to determine if an engine had failed or not. During the scan I noted the rudder trim indicated six left. I immediately began to retrim the rudder to zero. With the rudder at zero the aircraft was fully controllable. We had turned through about 180 degrees of heading. Tower told us to return to runway heading so the pilot at the controls continued the left turn to runway heading.

Data retrieved from NASA's ASRS site as of April 2012 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.

A G200 first officer discovered that an uncommanded left turn after takeoff was caused by rudder trim set at six degrees left. After the trim was zeroed the flight controls returned to normal and the aircraft returned to course.