On April 17, 1994, at 1135 central daylight time, a British Aerospace BAe-146, N609AW, operated by Air Wisconsin, Inc., as United Express flight 5272, had a fire warning in the number-two engine during climb after departure from Chicago O'Hare International Airport, Chicago, Illinois. The flight crew shut down the engine, activated the fire extinguisher, declared an emergency, and landed at O'Hare without further incident. There were no injuries to the four crew members, or 68 passengers aboard the airplane. There was no emergency evacuation. The flight was a domestic passenger flight, operating under 14 CFR Part 121, from Chicago to Lexington, Kentucky. Visual meteorological conditions prevailed at the time, and an IFR flight plan was filed. The captain stated he directed the first officer and the ground fire personnel to visually inspect the engine after the airplane cleared the runway. There was no sign of fire. The airplane was taxied to the gate, and the passengers were deplaned. When the number two engine was inspected, a loose fuel nozzle was found in the right hand fuel manifold. The fuel manifold was installed on this engine on February 5, 1994. The manifold had accrued 401 hours and 543 cycles since installation.