Skyhawk 172/Cutlass 172
Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 150; Flight Crew Total 330; Flight Crew Type 170
Workload; Troubleshooting; Situational Awareness
Aircraft Equipment Problem Less Severe; Ground Event / Encounter Loss Of Aircraft Control; Ground Excursion Taxiway
Flight Crew Took Evasive Action; Flight Crew Requested ATC Assistance / Clarification; General Maintenance Action
Aircraft
On the taxi out to take off both student and I performed initial brake check at slow speed and brake operation was normal. Continued taxi for takeoff and made two right turns with normal steering and brake operation. After crossing a runway the taxiway made a turn to the left; the student was at the controls and I noticed us veer from taxiway centerline to the right; slowly. Then after looking and verifying that she was making the correct control input on the rudder pedal and seeing the taxi continue to the left I applied my rudder and brake control to get back to the taxiway centerline and follow the left turn. With full rudder pedal deflection and full brake application on the left brake the airplane was still not controllable and exited the taxiway onto the grass at a slow speed. Upon rolling off the asphalt I shut down the engine and contacted ground and had the aircraft towed to maintenance. No damage was noted on the aircraft or on any airport equipment.
A C-172 Instructor reported the aircraft began veering right while taxiing while the student was under control of the airplane. The instructor took the controls and tried to turn to the taxiway but was unable and shutdown the engine as the aircraft exited the taxiway.