C172RG flight instructor reported steering issue during takeoff roll.

Attributes
ACN	1673465
Time
Date	201908
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	Takeoff
Route In Use	Other Local
Flight Plan	VFR
Person 1
Function	Instructor
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Flight Instructor Flight Crew Commercial
Experience	Flight Crew Last 90 Days 65 Flight Crew Total 750 Flight Crew Type 500
Events
Anomaly	Aircraft Equipment Problem Less Severe Ground Event / Encounter Loss Of Aircraft Control

Narrative:

Holding short of xxl on taxiway. Given clearance for takeoff. Student began taxi. Started drifting left. Applied right rudder. Kept drifting left. Applied more right rudder and brake. Kept drifting. Pulled power and full right rudder and brake. Instructor took controls and applied full right brake and rudder. Brake pedal went to floor. Left tire hit gravel and pulled plane to left. Spun plane 180 degree in gravel. No damage to aircraft; propeller; or taxiway lights observed.

Original NASA ASRS Text

Title: C172RG Flight Instructor reported steering issue during takeoff roll.

Narrative: Holding short of XXL on taxiway. Given clearance for takeoff. Student began taxi. Started drifting left. Applied right rudder. Kept drifting left. Applied more right rudder and brake. Kept drifting. Pulled power and full right rudder and brake. Instructor took controls and applied full right brake and rudder. Brake pedal went to floor. Left tire hit gravel and pulled plane to left. Spun plane 180 degree in gravel. No damage to aircraft; propeller; or taxiway lights observed.

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.