What happened
During an approach to land, the flight crew received an engine fire warning. The crew executed standard engine fire emergency procedures, which resulted in a successful single-engine landing. Following the aircraft's arrival, smoke was observed emanating from the #2 engine, prompting the Captain to order an evacuation of the Boeing 737.
The evacuation encountered several mechanical difficulties. When the 1R exit door was opened, the slide deployed automatically. However, the slides for exits 1L and 2R failed to inflate automatically and had to be inflated manually. During the process, a passenger exiting through the 1L door sustained a fractured ankle; a flight attendant noted that the passenger sat down and slid out rather than jumping as instructed.
Further complications occurred at exit 2L, where a flight attendant was initially unable to rotate the door handle. After receiving assistance from a passenger, the door was opened, but the escape slide inflated into the interior of the aircraft, effectively blocking both aft exits.
The investigation
An investigation into the equipment failures revealed that the operator had received approval for an alternate mean of compliance regarding AD 85-25-04. This airworthiness directive addressed modifications, testing, and inspections for escape slides on Boeing 737-100, 200, and 300 series aircraft.