Page:Aviation Accident Report - United Airlines Flight 4 - 17 October 1935.pdf/2

 Marks on the ground at the point of contact, made by the propellers, fuselage and engines, indicate that the airplane struck in a normal flying attitude. Marks made by the propellers and damage incurred by the propellers and internal parts of the engines indicate that both engines were running at normal speed. A knoll 3 feet higher and 60 feet away, which had to be crossed just prior to reaching the point of first contact, was not touched by the airplane, establishing that the plane was descending. This descent could have been the result of a slight change in the balance of the airplane not immediately noticed by the pilot. However, considering all factors, it seems more likely that the pilot was executing a power glide to the airport with the plane in normal flight attitude for that purpose.

A careful study of the wreckage failed to disclose any evidence of mechanical failure prior to the accident. Evidence that the airplane was in good mechanical condition was provided in a radio report by the crew to Cheyenne about five minutes before the accident to the effect that the airplane was functioning satisfactorily and could be used for the continuation of the trip east of Cheyenne, if desired. Also, entries made in the airplane log by the co-pilot during this flight indicated definitely that the airplane, engines, instruments and radio were functioning satisfactorily.

That no landing was attempted at this point is indicated by the fact that the landing gear was found to be in full retracted position, both engines were running at normal speed and neither landing flare had been used. The plane was in such a damaged condition as a result of the second contact with the ground that the position of the switches or controls as found could not be taken as definite proof of their position prior to the accident.

All indications are that the pilot was flying on instruments at the time of the accident. A log book entry made by the co-pilot credited the pilot with one hour of instrument flying, which may or may not have been completed at the time the entry was made. The rheostat controlling the the cockpit lights was in full bright position which is usual when flying at night by instruments. The radio was turned on the Cheyenne station with the volume turned low, as would be the case in an instrument approach, and the airplane was directly on the radio course.

Whether or not the pilot was flying entirely on instruments, the question still arises as to why he was flying so close to the ground at the point of first contact with the ground. It is possible that the co-pilot in giving their position as "Silver Crown" could have been observed that the airplane was approaching Silver Crown. The pilot hearing this over the interphones, might have taken this literally and started losing altitude faster or sooner than he should have from actual location. An additional 1,000 foot of altitude at the point of the accident would have placed the airplane in suitable position for a normal power glide to the airport for landing.

It is the opinion of the Accident Board that the probable cause of this accident was an error on the part of the pilot judging his altitude or his distance from the airport or both.

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