[1][2][5][6] The Piper, manufactured in 1946, was privately owned by Knopp[7] and departed from Soldotna Airport en route to Fairbanks.

Knopp had been denied a medical certification in June 2012 for vision problems; after an appeal, the denial was upheld in July.

[9][10] National Weather Service (NWS) reports from the Soldotna airport for Friday morning showed clear visibility, with broken clouds at 10,000 and 4,500 feet (3,000 and 1,400 m).

The report states that based on a visibility study both pilots could have seen the other airplane in the minute leading up to the collision, but also notes that the conditions on the incident date would have made this more challenging, and that Knopp would have needed to look almost directly at the sun to see the DHC-2.

It noted that the absence of airborne traffic advisory systems (not required at the time of the incident,) as well as Knopp's "decision to fly with a known severe vision deficiency" both were contributory factors.