B757-200
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown
ATC Issue All Types; Conflict Ground Conflict; Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Rejected Takeoff
Human Factors
Runway 10 cleared for takeoff. After First Officer calls 'Thrust Set' before 80 KTS. I look down the runway and mid- field a twin-engine Islander had taxied on runway and executed a takeoff. I started abort below 80 KTS. RTO Autobrakes did not engage. First Officer called Tower to alert abort and Tower questioned us as to why we aborted; informed about other aircraft and they did not know about or issue clearance to other aircraft. I taxied off runway. After abort rest of flight was normal.
A low-speed ABORT (Rejected Takeoff) was performed due to another aircraft accepting our take-off clearance; entering the runway mid-field; and taking off in front of us.
B757 flight crew reports a rejected takeoff when it is noticed that a light twin has accepted the clearance and is departing from mid field. The tower was not aware of the issue and questioned the reject by the B757 crew.