While on training flight the student and instructor aboard a beech texan ii encountered un-commanded...

Attributes
ACN	1240912
Time
Date	201502
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.TRACON
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	T6A Texan II / Harvard II (Raytheon)
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	IFR
Component
Aircraft Component	Rudder Trim System
Person 1
Function	Instructor Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine Flight Crew Instrument Flight Crew Flight Instructor
Experience	Flight Crew Last 90 Days 1027 Flight Crew Total 18707 Flight Crew Type 12017
Events
Anomaly	Aircraft Equipment Problem Less Severe

Narrative:

While holding over ZZZ on an instrument training flight; I felt a significant left yaw and noticed the 'ball' deflect fully to the right. I asked the student if he were applying left rudder; and he told me that he was not. I took the flight controls from the student and noticed that I had to put in significant rudder pressure to center the 'ball.' I opened my emergency procedures checklist to the runaway trim procedure; and executed those emergency procedures. I contacted approach; told them that I had a flight control malfunction; and asked to go back to the base. On the way I climbed to 7;000 MSL; and performed a controllability check. The airplane was controllable with heavy rudder pressure down to our final approach speed; so I elected to land. The landing was uneventful.

Original NASA ASRS Text

Title: While on training flight the student and instructor aboard a Beech Texan II encountered un-commanded rudder displacement that they could not trim out but could overcome with pedal pressure. They returned to their departure airport and landed uneventfully.

Narrative: While holding over ZZZ on an instrument training flight; I felt a significant left yaw and noticed the 'ball' deflect fully to the right. I asked the student if he were applying left rudder; and he told me that he was not. I took the flight controls from the student and noticed that I had to put in significant rudder pressure to center the 'ball.' I opened my emergency procedures checklist to the runaway trim procedure; and executed those emergency procedures. I contacted Approach; told them that I had a flight control malfunction; and asked to go back to the base. On the way I climbed to 7;000 MSL; and performed a controllability check. The airplane was controllable with heavy rudder pressure down to our final approach speed; so I elected to land. The landing was uneventful.

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.

While on training flight the student and instructor aboard a beech texan ii encountered un-commanded rudder displacement that they could not trim out but could overcome with pedal pressure. They returned to their departure airport and landed uneventfully.