Incident Overview
After a gate delay to accommodate late passengers, the flight received clearance for takeoff on Runway 28L. Approximately four seconds after rotation speed was called, the stickshaker activated, prompting the crew to abort the takeoff. A cockpit voice recorder (CVR) readout indicated that the thrust reversers were deployed 11 seconds later. The aircraft came to a stop in the dirt overrun, about 50 feet beyond the end of the runway.
Damage and Injuries
The aircraft sustained only minor damage, and no injuries were reported.
Investigation Findings
Prior to its departure from Seattle, Washington, the aircraft had been placarded for an inoperative anti-skid system. The investigation revealed that the right flap position transmitter had malfunctioned due to corrosion. According to the investigation, a malfunction of either flap position transmitter can send an erroneous flap setting signal to the stall warning computer. This, in turn, activates the stickshaker/stall warning system at incorrect airspeeds.