Event Summary
While cruising at Flight Level 330, the crew received a fire warning light and bell for the #2 engine. Following published procedures, they shut down the engine and discharged a fire bottle. The aircraft then diverted to Cincinnati for a precautionary landing.
After landing, fire department personnel monitored the aircraft and relayed information to ground control. While the aircraft was taxiing, ground control passed that information to the flight crew. Fire truck personnel had reported seeing a small amount of smoke from the #1 engine, but ground control relayed the information without specifying the amount.
The aircraft was subsequently stopped, and passengers evacuated using the escape slides.
Evacuation and Injuries
During the evacuation, one passenger was seriously injured when a slide burst. Evidence indicated the slide was punctured by a nail from a shoe after the shoe's heel came off.
Additional evacuation issues were noted. One flight attendant unlatched a girt bar before opening exit 4R, rendering that exit unusable. Some passengers attempted to exit while carrying carry-on baggage. The rear stair exit was not used during the evacuation.
Investigation Findings
Investigation revealed the fire warning was false, caused by a shorted fire detector in the #2 engine. The flight attendants had not been properly briefed for the emergency.