On March 4, 1994 at 1450 central standard time, an Aerospatiale ATR-72, N253AT, operating as American Eagle flight 3740, experienced an engine cowling fire while taxiing at the DFW Airport, Dallas/Fort Worth, Texas. The four crew members and 52 passengers were not injured. Visual meteorological conditions prevailed for the intended 14 CFR Part 121 flight. In the Pilot/Operator report, the pilot stated that the number one engine fire warning light illuminated. He further stated that he and the co-pilot performed the emergency checklist and then evacuated the passengers out of the rear door of the aircraft. The fire was suppressed by the crew using the published emergency procedures. A detailed examination of the aircraft by the operator revealed that the No. 1 engine drain manifold was blocked with "coking" deposits. The operator also stated that "internal pressure caused a fuel spill inside the nacelle with resultant fire."