After the aircraft arrived on top of the overcast at about 6000 feet altitude, the captain and first officer oriented themselves and subsequently effected a landing at Burbank via the Los Angeles radio range. The landing was uneventful except for the malfunctioning of one brake which necessitated ground-looping in order to stop. The aircraft was then towed back to the hangar.
Captain Davis' course from the time he took his 160-degree departure from what he mistakenly thought was the Newhall cone of silence was such that he could only have entered the influence of the Newhall Fan Marker along its southwesterly edge. The Newhall Range itself was functioning normally at that time. This was ascertained by the captain of United Air Lines Trip No. 71 which left Burbank, northbound, at 9:22 a.m. He reported, at the request for information by the Burbank Control Tower that the Newhall Fan Marker was functioning normally. This report was received while Trip 71 was still contact. The captain of a Western Air Express plane reported at 9:47 a.m. that the Newhall range was emitting normal "A" and "N" quadrant signals while that flight was over Grand Central Air Terminal.
The testimony of the pilot definitely establishes that he mistook the termination of a multiple of the Newhall Range located about nine miles north for the Newhall cone of silence; his subsequent navigation offers conclusive evidence of this mistake. The existence and the limitations of this multiple of the Newhall Range are well known and well established. The range was flight-checked the following day by personnel of the Civil Aeronautics Administration and found to be operating normally. His testimony also revealed that he had, four or five minutes before changing his course to 160 degrees, passed through an area of broken clouds, allowing a view of the terrain below, and that he had an opportunity to check his ground position at that time. The aircraft's barograph indicated that the aircraft descended to an altitude of about 3,400 feet, the altitude of the terrain on which the tree was struck. The site of the tree was about five and one half miles southwest of the Newhall Range Station, and approximately four miles west of the course.
After passing the Newhall Range Station, southbound, the Newhall Fan Marker's zone should be entered in approximately one minute. The captain's action in not definitely checking the Newhall Range Station by its noise level build-up, as well as its cone of silence, was a mistake. He then arbitrarily added 20° to his turn to allow for wind drift. Although this is a large correction, it would not, in itself, have caused the accident had not the original mistake been made. However th(illegible text) was followed by a second mistake when the captain failed to realize that he was not where he should have been when he did not hear the Newhall Fan Marker within one minute after his initial change of course.