Date: 201904
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: Saab 340 Undifferentiated
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: Normal Brake System
Component problem: Failed
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Aircraft Equipment Problem Critical; Ground Event / Encounter Loss Of Aircraft Control; Ground Excursion Runway
Detector: Person Flight Crew
When detected: Other Takeoff roll
Result: Flight Crew Rejected Takeoff
Contributing factors: Aircraft; Company Policy
Primary problem: Aircraft

Narrative: After being cleared for takeoff; and completing the runway items checklist; I advanced the power levers and instructed the First Officer to set power. He brought the CTOT (Constant Torque on Takeoff) switch to the APR (Automatic Power Reserve) armed position and said that the auto coarsen was high. At this point the aircraft started veering to the left; and was not responsive when I used the tiller to correct the aircraft back onto the runway centerline. It was in this moment that I called for the abort; applied brakes and brought the power levers into reverse. The aircraft then moved towards the right side of the runway. The aircraft had slowed down at this point; so I brought the power levers out of reverse and realized that brakes were not responsive. I took the immediate action; and executed the loss of braking memory item; Antiskid Switch Off; with no response. When it was evident that the aircraft would be going off the runway; I moved the condition lever to the fuel off position; so as not to hit anything. The aircraft stopped rolling on the east side of the runway past taxiway XX. After Dispatch and ATC were spoken with; I then notified the FA (Flight Attendant) and passengers about what had occurred. Consideration should be given to adding another check of the hydraulic system the runaway items checklist.


Second narrative: After being cleared for takeoff the Captain advanced the power levers and advised me to set power. I responded auto coarsen high; and the aircraft started veering to the left. Once the Captain realized that directional control was lost we aborted the takeoff and advised ATC that we were aborting our takeoff. At this point the aircraft started veering back to the right (at a speed no more that roughly 20kts) hydraulic pressure seemed to be lost and from the right seat I applied pressure to my brakes and no response/braking action occurred. After realizing loss of braking; the Captain turned anti-skid switch off. The aircraft at this point continued off to the right of the runway and into the grass where we were still unable to have braking action on the applied breaks. The aircraft eventually came to a slow stop in the grass on the right/east side of the runway just pass XX taxiway. Consideration should be given to add one more checklist item of the hydraulic system before takeoff.


Synopsis: Saab 340 flight crew reported a rejected takeoff and loss of braking control thereafter.