Editing The Day the Music Died (section)

==Official investigation==
The official investigation was carried out by the [[Civil Aeronautics Board]] (CAB, precursor to the [[National Transportation Safety Board|NTSB]]). It emerged that Peterson had over four years of flying experience, of which one was with Dwyer Flying Service, and had accumulated 711 flying hours, of which 128 were on Bonanzas. He had also logged 52 hours of [[Instrument flight rules|instrument flight training]], although he had passed only his written examination, and was not yet qualified to operate in weather that required flying solely by reference to instruments. Peterson and Dwyer Flying Service itself were certified to operate only under [[visual flight rules]], which essentially require that the pilot must be able to see where the aircraft is going. On the night of the accident visual flight would have been virtually impossible due to the low clouds, the lack of a visible horizon and the absence of ground lights over the sparsely populated area.<ref name="CAB1"/>
{{multiple image
 | total_width       = 400
 | image1            = VMS Artificial Horizon.jpg
 | caption1          = A conventional artificial horizon: sky on top, ground at the bottom
 | image2            = Sperry F3 artificial horizon.svg
 | caption2          = A Sperry F3 attitude gyroscope: ground on top, sky at the bottom
}}

Furthermore, Peterson, who had failed an instrument [[FAA Practical Test|checkride]] nine months before the accident, had received his instrument training on airplanes equipped with a conventional [[artificial horizon]] as a source of aircraft attitude information, while the accident aircraft was equipped with an older-type Sperry F3 attitude [[gyroscope]]. Crucially, the two types of instruments display the same [[Flight dynamics (fixed-wing aircraft)|aircraft pitch attitude]] information in graphically opposite ways. As a result, when the aircraft took off, Peterson, observing the older model Sperry F3 gyroscope, thought he was climbing when in fact he was descending.<ref name="CAB1"/>

Another contributing factor was the "seriously inadequate" nighttime weather briefing provided to Peterson, which "failed to even mention adverse flying conditions which should have been highlighted".<ref name="CAB1"/> The CAB concluded that the probable cause of the accident was "the pilot's unwise decision" to attempt a flight at night that required skills he did not have.<ref name="CAB1"/>