Flight Crew Total 4000
Aircraft Equipment Problem Critical
Flight Crew FLC complied w / Automation / Advisory; Flight Crew Overcame Equipment Problem; Flight Crew Took Evasive Action; Flight Crew Rejected Takeoff; General Flight Cancelled / Delayed; General Maintenance Action
Aircraft
Taking Runway 24 for departure we lost Number 1 Hydraulic Quantity when the flight taxi switch was moved to the flight position. It was detected by the loss of normal brakes; the roll spoiler inboard hydraulic caution light; and the Number 1 ISO valve caution light. We briefly discussed that we had lost Number 1 Hydraulic quantity. We decided that with nose wheel steering; deicing; and the emergency brake that we could safely return to the gate. We notified ATC and company. Then returned to the gate. The First Officer made a PA and talked to the Flight Attendant. I was not able to use the normal brakes. The Roll Spoiler inboard hydraulic caution light and Number 1 ISO Valve caution light illuminated. The number 1 hydraulic fluid gauge was at 1 quart. Maintenance told us that a hydraulic actuator had cracked and dumped fluid overboard. We discussed what had happened. Then determined that we had what we needed to return to the gate and did so.
A DHC-8-100 hydraulic actuator failed which dumped the Number 1 Hydraulic System fluid overboard as the takeoff was begun; so the takeoff was rejected; but the crew had sufficient brakes and steering to taxi to the gate.