The pilot, a senior airline captain, had recently purchased a Cessna 172 and was flying it home.
Flying under VFR at night, he switched with an approach controller about 52 NM from the destination airport. After a while, the air traffic controller noticed the airplane was descending below the asigned altitude of 7500 ft. and radioed the pilot.
The pilot did not respond to the controller’s radio calls, and the small airplane crashed in pastureland about 17 miles from the destination airport.
Examination of the wreckage revealed that the airplane collided with trees at a very shallow descent angle.
A review of the pilot’s actions during the nine days prior to the accident revealed that he flew a five-day international trip and then returned to Zurich three days before the accident. About four hours later, he began a trip as a passenger to Colorado.
On the day before the accident, he began the first of three legs of a cross-country flight, with the third leg the accident flight. He was awake for about 18 hours at the time of the accident, with stops only for food and airplane servicing.
Over the nine-day period before the accident, the pilot made three crossings of the Atlantic Ocean (each exceeding six time zones). These multiple and frequent time zone crossings would result in circadian disruption and would have diminished the pilot’s ability to obtain restorative sleep during this period, which, in combination with his extended time awake on the day of the accident, would have caused him to be in a fatigued state.
The circumstances of the accident and his fatigue-inducing schedule in the preceding days indicate that the pilot most likely fell asleep during the initial descent for landing, and the airplane subsequently descended into the trees and terrain.