Douglas DC-3 accident at Laramie, Wyoming, 17 Oct 1946

Accident narrative

On October 17, 1946, a Douglas DC-3 operated by NATS Air Transportation Service crashed near Laramie Airport in Laramie, Wyoming, while attempting an approach under extremely adverse weather conditions. The aircraft was demolished by the impact, and all 13 occupants were fatally injured.

### The flight

The non-scheduled flight was arranged between Oakland, California, and Newark, New Jersey, with a scheduled first stop in Cheyenne, Wyoming. The aircraft, referred to in the report as Aircraft 942, departed Oakland Municipal Airport at 1842 on October 16 under an instrument flight rules clearance to Cheyenne, with Denver, Colorado, as its alternate airport.

The crew consisted of Captain Clarence R. V. Abernathy, who had accumulated 3,222 flight hours including 840 in DC-3 equipment; Co-pilot Harry K. Holle, who had 1,500 hours; and Stewardess Dorothy Ann Hartman.

### Sequence of events

Prior to departure, meteorologists from the Flight Advisory Weather Service briefed the pilots that difficult flying conditions, icing up to 16,000 feet, and ceilings below instrument minimums could be expected. The captain indicated he expected a difficult flight but intended to proceed as originally planned.

Airway Traffic Control (ATC) cleared the flight via Airway Green 3, eventually instructing it to cruise to Cheyenne at 15,000 feet. By 2154, Cheyenne weather was reported as a 100-foot ceiling and 1/2-mile visibility. As the flight progressed, ground stations relayed worsening weather reports. Over Rock Springs, the flight was advised that Cheyenne had dropped to zero ceiling and zero visibility in dense fog and light drizzle.

The flight contacted Sinclair Radio and reported difficulty with its airspeed indicators, stating a change in flight plan would be requested from Laramie Radio. No further mention of the airspeed indicators was made in subsequent radio contacts.

At 0005 on October 17, the flight reported over Laramie. Laramie Radio informed the pilot of an indefinite 400-foot overcast ceiling and 20 miles visibility in light rain. The pilot requested a flight plan change to land at Laramie. Denver ATC initially cleared a descent to 11,000 feet if visibility remained at 3 miles, but the pilot replied he was in clouds at 14,000 feet and could not descend under contact flight rules. An amended clearance instructed the flight to descend on the southeast leg of the Laramie Radio Range.

At 0025, the flight reported descending. Later, while the aircraft was outbound preparing for its final instrument approach, Laramie Radio transmitted a weather observation reporting a precipitation ceiling of zero feet, an obscured sky, and visibility of 2 miles in light snow.

Denver ATC became apprehensive about the rapidly lowering weather at Laramie and checked other airports, finding that Sheridan, Wyoming, was satisfactory for contact operations. At 0050, Denver ATC instructed Laramie Radio to ask the flight for its remaining fuel and suggest proceeding to Sheridan. By this time, Laramie's visibility had fallen to 1/2 mile in snow. However, no further radio contact was made with the aircraft.

The aircraft was first seen passing over the airport at a low altitude. At approximately 0053, a Laramie communicator standing outside heard the aircraft pass over the field at a low altitude in an easterly direction. The engines stopped suddenly, followed by a sound resembling an impact with the ground.

### What the investigation found

Search efforts located the wreckage approximately one mile northeast of Laramie Airport. The investigation found that the aircraft had been heading northerly when its left wing tip struck the ground while in a left bank of at least 70 degrees. The aircraft dragged along the ground for 75 feet, the left wing failed, and the aircraft disintegrated as parts were strewn over an additional 950 feet.

Examination of the wreckage revealed that the landing gear was extended. Damage to the propellers indicated both engines were developing considerable power at impact. Investigators measured approximately 150 gallons of gasoline remaining in the tanks, estimating another 20 gallons had escaped from broken lines. The Board found no indication that any part of the aircraft had malfunctioned in flight.

Weather analysis showed a stationary front near Laramie causing low ceilings and poor visibility. While en route, the Denver Weather Bureau had forecast Cheyenne and Laramie weather to lower further, but these forecasts were not transmitted to the flight, as neither ATC nor the pilot requested them. The Board noted that Flight Advisory Weather Service personnel in Salt Lake City and Denver were unaware of the flight and were not asked for assistance by ATC, indicating a lack of clear definition of responsibilities between the Civil Aeronautics Administration and the Weather Bureau.

The Board concluded that the pilot exercised poor judgment by failing to select an alternate airport outside the frontal system and by failing to request later weather forecasts. The Board further questioned his judgment for making repeated attempts to align with a runway at Laramie in extremely adverse weather, noting that the aircraft passed over the field at least three times during a 12-minute period maneuvering beneath the overcast. With almost two hours' fuel aboard, the Board noted it would still have been possible to proceed to a suitable alternate. The Board believed that in attempting to keep the field in sight while circling at a very low altitude, the pilot evidently momentarily lost control by banking excessively.

### Probable cause

The Board determined that "the probable cause of this accident was the action of the pilot in maneuvering the aircraft at a dangerously low altitude under extremely adverse weather conditions in an attempt to land. A contributing factor was the negligence of the pilot in planning a flight into an area in which adverse weather conditions were forecast without making adequate provisions for a suitable alternate airport."