Kennedy's plane flew into the same path of American Airlines Flight 1484, which was on the approach to Westchester County Airport.
- Late departure
The flight was originally scheduled for daylight hours, but had to be postponed after Kennedy's sister-in-law was delayed at work. Heavy traffic further delayed Kennedy's flight and pushed it back until after dark. Originally planned to depart at 6:00 p.m., Kennedy's plane departed at 8:39 p.m. instead, nearly a half-hour past sunset. At the time of the takeoff, the moon was just above the horizon and provided very little illumination.
- No flight plan or request for help
Kennedy never received a weather briefing or filed a flight plan with any Flight Service Station. Except for the take-off portion of his flight, Kennedy did not contact any air traffic controllers; during the flight, he never requested help or declared an emergency.Under the conditions of his flight, Kennedy was not required to file a flight plan, and because he did not, no one knew his exact route or expected time of his arrival. According to the Weather Service International, Kennedy made two weather requests before taking off. The information he was provided indicated that visibility ranged from 10 miles along his route to four miles at Martha's Vineyard.
- Flight over featureless, open water
Shortly after passing Point Judith, Rhode Island, Kennedy's plane headed directly towards Martha's Vineyard. Instead of following the coastline of Rhode Island Sound and Buzzards Bay, which would have provided visible lights on the ground, Kennedy chose the shorter, direct path over a 30-mile (50 km) open stretch of water. According to the FAA Airplane Flying Handbook, crossing large bodies of water at night may be very hazardous, not only from the standpoint of ditching in the water, but also because the featureless horizon visually blends with the water, in which case depth perception and orientation become difficult.
- Foot injury
Six weeks before the crash, Kennedy had fractured his left ankle in a paragliding accident. He had surgery, wore a cast, and walked with a cane up until the night of the accident. During his interviews, Kennedy's orthopaedic surgeon stated that, at the time of the crash, he would have been able to apply the type of pressure that would normally be required to drive a car.
- Incorrect radio frequencies
While the NTSB examined the wreckage, they soon discovered that both of Kennedy's radios had incorrect frequencies selected. Kennedy had accidentally selected 127.25 for Martha Vineyard's ATIS instead of 126.25; likewise, he selected 135.25 for Essex County ATIS, but it should have been 135.5. The NTSB declined to comment on the contribution this factor had in the crash, if any...."