HAWK MK 67 N509XX accident near Oklahoma City, Oklahoma

Probable cause

The loss of directional control during the takeoff roll for reasons that could not be determined during postaccident examinations and testing.

NTSB analysis

The pilot was on a cross-country flight in a single-engine jet trainer and had stopped en route for refueling. The pilot reported that, during the takeoff roll, as the airspeed reached about 90 knots, the airplane made a hard left turn. He applied the right rudder and brake to stop the left turn; however, the airplane continued left off the runway surface and then came to rest upright.

Examinations of the tires, wheel brakes, and rudder did not reveal any abnormalities. The nosewheel steering control unit was bench tested. During the test, the unit's power supply module failed; however, it was determined that a supply failure would cause a castering nosewheel rather than an uncommanded steering input. The reason for the uncommanded turn could not be determined.

Text from the NTSB. Open the NTSB docket for CEN15TA019 for the full record.