Date: 201406
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Dusk
Aircraft: EMB ERJ 145 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
Airspace: Class B ZZZ
ATC / advisory: Tower ZZZ
Aircraft component: Nosewheel Steering
Component problem: Design; Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Confusion
Anomaly: Aircraft Equipment Problem Critical; Ground Event / Encounter Other / Unknown
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Rejected Takeoff; Flight Crew Returned To Gate; General Maintenance Action; General Flight Cancelled / Delayed
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Captain's leg; takeoff on Runway 22L. At around 60 KT I felt a sharp 'yank' force on the yoke and decided to abort the takeoff; thinking we have hit an object or the steering has failed. We determine that the steering works normally and have no EICAS messages. We taxied clear of the runway and I call Maintenance Control. We reset the steering; and the Maintenance Controller advises no history of steering anomalies on this aircraft. We had advised Tower of possible FOD on the runway; but the resulting FOD check was negative. Brake Temperature and Fuel Status are OK; so First Officer and I are both comfortable trying another takeoff. Taxi back to [Runway] 22L; begin takeoff roll. Passing 100 KTS; I feel the 'yank' again only this time followed by two sharp pulls to the left; so I execute a high speed abort. Brake temperatures are OK to taxi; and steering works again with no EICAS messages. We taxi directly back to a gate and deplane. Maintenance notified; and the aircraft was towed away to Maintenance. Aircraft [was] under positive control at all times. Takeoff roll; steering malfunction; flight delayed.

Callback: Reporter stated he felt the violent 'yank' force with his left hand on the Control Yoke; not the Steering Tiller. The reset procedure for the nose steering was accomplished under the guidance of Maintenance Control by setting the brakes and Opening/Closing (resetting) the Brake Steering Circuit Breaker (C/B). After the second takeoff attempt and similar violent 'yank' and two sharp pulls to the left; Maintenance needed to get involved with the trouble shooting; they were done with the aircraft. Reporter stated they do get simulator time experiencing sudden uncommanded steering turns and how to minimize the effects by keeping hands 'off' the Tiller and using 'differential braking' for steering. But; even with that training; one of their senior pilot's had experienced the exact same event during takeoff; except the uncommanded turn was more radical with the EMB-145 ending up in a grassy area. He does not know if the Brake Steering Unit or Tiller handle internal electrical potentiometer was replaced on his EMB-145 aircraft.



Synopsis: A Captain describes the violent; sharp 'yank' force he felt on the Control Yoke during two takeoff rolls that included two sharp pulls to the left; resulting in two Rejected Take-Offs (RTOs) on the same EMB-145 aircraft. No EICAS messages displayed.