Douglas DC-3 accident at Trammel, Kentucky, 28 Jul 1943 (G-102)

Accident narrative

On July 28, 1943, at about 10:43 p.m. Central War Time, an American Airlines Douglas DC-3 crashed about one mile west of Trammel, Kentucky. The aircraft, operating as Flight 63, struck the ground in nearly level flight and was completely destroyed by impact and fire. All four crew members and sixteen passengers, including an infant, were fatally injured. Two passengers escaped with serious injuries.

### The flight

Flight 63 was a scheduled service between Cleveland, Ohio, and Memphis, Tennessee, with intermediate stops at Columbus, Dayton, Cincinnati, Louisville, and Nashville.

The crew consisted of Captain Harry A. Stiller, First Officer Robert M. McClure, and Stewardess Josephine Kane, a registered nurse. Captain Stiller had accumulated approximately 4,315 flying hours, with about 2,700 hours in DC-3 equipment. First Officer McClure had approximately 970 hours of flight time. Also aboard was Captain Bayard A. Carpenter, a veteran pilot with over 15,244 flight hours, who was assigned to the flight for route familiarization.

The aircraft was a Douglas DC-3 equipped with two Wright G-102 engines and Hamilton Standard Hydromatic propellers.

### Sequence of events

The flight departed Cleveland at 5:42 p.m. Eastern War Time. En route from Dayton to Cincinnati, the trip encountered adverse weather and unreported military traffic, prompting a return to Dayton. After a delay of 30 to 40 minutes, the flight proceeded to Cincinnati and then to Louisville, landing at 9:42 p.m. Central War Time.

Before taking off from Louisville, Captain Stiller requested a change to his flight plan, asking to proceed to Smiths Grove, Kentucky, at 2,500 feet and continue to Nashville at 2,000 feet. This change was approved. The flight departed Louisville at 9:54 p.m.

At 10:22 p.m., because static interference prevented direct communication with Nashville or Louisville, the flight contacted the Smiths Grove airways communication station. The crew reported they estimated being over Smiths Grove at 10:29 p.m. at 2,500 feet. At 10:28 p.m., the flight advised the station of an aircraft three miles south of Smiths Grove at 5,000 feet. The operator informed the flight that it was an Army plane practicing on the range. The flight acknowledged this information, which was the last message received from the aircraft.

Two passengers survived the crash, both of whom were pilots. Lieutenant Fellows, an Army pilot occupying the extreme front right seat, stated he was awakened five or ten minutes before the crash by severe turbulence. He saw an unusually severe storm ahead with heavy rain and intense lightning. He noted a sudden change in pressure, his ears blocked, and he felt a "light feeling on the seat" which indicated a sudden loss of altitude he estimated at not much over 500 feet. He stated there was a greatly increased application of power immediately before the airplane struck the ground.

The other survivor, Mr. Samuel Kurtz Hoffman, an aircraft engine manufacturer's chief engineer, was seated in the third row from the rear. He observed lightning on all sides and felt the airplane was losing altitude in a general glide. He noted that the engines were throttled back shortly after entering the storm, and then opened up immediately before hitting the ground.

### What the investigation found

The wreckage was located on the airway less than two miles from the "on course" signal of the Smiths Grove Radio Range. The rolling terrain varied from 695 to 720 feet above sea level. Marks on the ground and trees revealed that the aircraft, while laterally level and descending about 11 degrees from horizontal, first struck a grove of trees 16 feet above the ground. It struck the ground 85 feet beyond the trees and proceeded forward about 1,000 feet. The right wing was sheared off by a large tree just prior to the fuselage coming to rest, and the left wing was bent upward and over the fuselage. The right engine tore loose and rolled 500 feet; the left engine rolled 375 feet.

Examination of the wreckage revealed no evidence of mechanical or structural failure in flight. Both engines were functioning normally at the time of impact, and propeller settings indicated power was being applied. There was no indication of fire before the initial impact. Although the radio and instruments were demolished, the flight's recent communication and position directly on course indicated they had been functioning properly.

The coroner stated that the three pilots were found thrown clear of the airplane. Three passengers were found in the front of the cabin, one in the aisle, and the remaining victims were piled against the rear cabin door. Because the slight descending angle and the trees broke the fall, the Board assumed the passengers were not seriously injured by the crash itself, but had crowded the cabin door in an effort to escape the flames.

Mr. Hoffman testified that he tried to open the main cabin door from the inside but could not budge it, eventually escaping through a hole in the fuselage. The DC-3 was equipped with a safety latch, which Hoffman was unaware of, but the Board believed that severe distortion of the fuselage caused by the impact had jammed the door and emergency exits. Hoffman noted that the cabin door swung open of its own accord about half an hour after the crash, which the Board believed was due to heat from the fire releasing the jam.

Weather analysis indicated that a severe thunderstorm had developed in the Trammel area. Local witnesses described the wind, rain, and lightning as the most violent they had ever experienced. An Army pilot flying a B-24 in the area reported the lightning was so bright he had to avert his eyes.

It appeared quite conclusive that strong surface winds in the area resulted from a vigorous downdraft fanning out from the thunderstorm. The Board estimated the flight encountered a downdraft with a vertical component of at least 1,500 feet per minute. Assuming the crew maintained constant power and airspeed, the airplane would have lost altitude at a rate substantially equal to the descending air. Even if the pilot increased the angle of attack to climb, the descent would likely have approached 1,000 feet per minute.

To explain why the descent continued until the airplane struck the ground, the Board offered a possible explanation: as the downdraft approached the ground and fanned out horizontally, the airplane may have passed out of the downdraft and into a high-velocity tailwind. This would have caused an immediate loss of airspeed and lift, requiring the airplane to accelerate along its flight path at a time when its angle of attack may already have been near a stall. While noting this was speculative, the Board stated that the atmospheric conditions within the storm were such that the airplane could easily have been forced down from its 1,300-foot absolute altitude without any other contributing factors.

American Airlines' chief pilot testified that Captain Stiller was an above-average pilot and was in complete command of the flight, with Captain Carpenter available in an advisory capacity. Company policy advised pilots to avoid thunderstorms for safety and passenger comfort, but did not forbid flying through them, leaving the decision to the pilots' discretion. The Board assumed that, based on their combined experience, the crew entered the storm area with full confidence that it could be negotiated safely.

### Probable cause

The Board determined the probable cause of the accident was "loss of control of the aircraft due to unusually severe turbulence and violent downdraft caused by a thunderstorm of unknown and unpredictable intensity."