Event
After activation of the No. 1 engine fire warning signals a second time, the flight crew declared an emergency and returned for landing. During the return, the aircraft conducted a fuel dump. Some ground observers observed the fuel dump as a smoke trail and reported this to the flight crew. An aircraft waiting for takeoff reported that no smoke or fire was visible, but noted the fuel dump was still in progress; this transmission was overridden by other communications.
Evacuation
After the aircraft came to a stop on the runway, an emergency evacuation via slides was initiated. Eight passengers sustained reported injuries during the evacuation.
Investigation
The fire warning activation was traced to a short-circuit in the system. The aircraft was repaired and subsequently returned to service.