Douglas DC-3 accident at Chicago, Illinois, 2 Jul 1946 (G-202A)

Accident narrative

On July 2, 1946, a Transcontinental and Western Air Douglas DC-3 made an emergency wheels-up landing approximately 13 miles northeast of the Chicago Municipal Airport after both engines failed in flight. The 21 occupants sustained minor injuries, and the aircraft was extensively damaged.

**The flight**

Transcontinental and Western Air Trip 456 was scheduled to depart Chicago Municipal Airport at 0900 for La Guardia Field in New York, with an initial stop in South Bend, Indiana. The aircraft, a Douglas DC-3 equipped with Wright G-202A engines and Hamilton Standard propellers, was within its maximum gross weight limits.

The crew consisted of Captain S. J. Gracey, who had 2,559 hours of flying time including 2,261 hours in DC-3 equipment; First Officer T. J. Conley, who had 2,939 total hours; and Stewardess L. Backus.

**The sequence of events**

The flight departed Chicago under Contact Flight Rules at 0909. At an altitude of 600 feet, the left engine failed with no prior warning. The first officer began emergency single-engine procedures, though the propeller was not feathered, and contacted the Chicago control tower to advise that the flight intended to return. The captain maintained control and entered a left turn to avoid residential areas to the south and position the aircraft for landing.

After approximately 90 degrees of turn, the right engine also failed with no prior indication of difficulty. Realizing the aircraft could not reach the airport, the captain selected a field adjoining the Chicago Belt Railroad. He maneuvered to avoid large buildings and residential sections east of the field. At an altitude of less than 100 feet, the first officer was instructed to extend the flaps, and the aircraft descended with the landing gear retracted.

First contact was made approximately 150 yards east-northeast of the railroad embankment. The left wing struck a telephone pole, breaking it in two. The aircraft skidded toward the embankment, passed underneath the telephone wires, and came to rest on the railroad track facing its flight path.

The first officer turned off the battery, individual engine ignition switches, and moved the mixture controls to idle cut-off. The occupants quickly deplaned. Seeing no danger of fire, the captain re-entered the cockpit and turned off the fuel selector valves.

**What the investigation found**

The aircraft was extensively damaged. The left wing was almost severed 12 feet outboard of the left engine, both nacelles and the center section were warped and broken, and the right engine was almost completely torn from its nacelle. The fuselage was wrinkled rearward as far as the cabin door, though the empennage was undamaged. Damage to the engines and ground marks indicated conclusively that both propellers were windmilling without power at the time of impact.

The captain and first officer testified that fuel pressure for the left engine dropped to approximately 7 pounds at the time of power loss, and that both fuel pressure warning lights were illuminated after the right engine failed. Neither pilot noted any surging, vibration, or roughness before the power loss.

Investigators found the left auxiliary fuel tank was empty, while the left and right main tanks contained approximately 130 gallons each at takeoff. Exhaustive inspections of the fuel system revealed no evidence of mechanical failure. The fuel tank selector valves were properly rigged, lines were intact with no leaks, and no water was found in the system. The engine-driven pumps and auxiliary pumps worked perfectly, with the auxiliary pumps providing approximately 300 gallons per hour during testing. The selector valves showed no leakage under suction tests ranging from 0 to 20 inches of mercury. Both carburetors and the ignition systems functioned satisfactorily.

The engines were removed and sent under seal to the airline's overhaul shops in Kansas City. With the exception of three damaged cylinders that were replaced, the engines were mounted on test stands with their original components. Both engines operated normally at several power settings, including takeoff power.

The Board noted that the requirement for a dual fuel system was specifically intended to prevent mechanical failure or vapor lock from affecting both engines simultaneously. Finding no material malfunctioning, the Board concluded that the only valid cause for the engine failures was fuel starvation, such as the exhaustion of the fuel supply in flight. Flight tests demonstrated that taking off on a tank with only enough fuel to reach 600 feet would produce similar engine stoppage.

However, both pilots testified that they had set the fuel selector valves to the left and right main tanks before starting the engines and had not moved them until after the aircraft came to rest. Because of this testimony, the Board found it manifestly impossible to determine the exact cause of the accident.

**Probable cause**

The Board determined that the probable cause of this accident was "the complete loss of power in both engines due to fuel starvation necessitating an emergency landing in an unfavorable area. The cause for fuel starvation of the engines has not been determined."