A report by the National Transportation Safety Board (NTSB) cited selfies or 'self-photographs' to have contributed to the 31 May plane crash in Colorado.
Video footage from an undamaged GoPro video camera found near the wreckage revealed the pilot and passenger were taking several selfies with flash prior to the plane crash, said the report.
The phone use is said to have "distracted the pilot" and caused him to develop spatial disorientation and lose control of the two-seat Cessna 150.
The report said: "Based on the evidence of cell phone use during low-altitude manoeuvering... it is likely that cell phone use during the accident flight distracted the pilot and contributed to the development of spatial disorientation and subsequent loss of control.
"The camera's flash was activated and illuminated the cockpit area."
While the fatal crash was not caught on camera, investigators found nothing else that might have contributed to the crash.
The crash resulted in the death of the 29-year-old pilot Amritpal Singh and his passenger.
Singh had an estimated experience of 726 total flight hours and 27 hours of experience flying at night.