Accident Summary
The accident occurred during the fourth leg of a night cargo flight. The aircraft was cruising at approximately 500 feet above ground level en route to Mount Vernon, Illinois. While in cruise, the aircraft struck trees and subsequently collided with the ground.
Pilot Information
The pilot stated that he did not recall the crash sequence. At the time of the accident, he was wearing a "walkman" radio. He reported using the device to help keep himself awake, as he had previously experienced episodes of falling asleep while flying night cargo flights.
Mechanical Examination
After the accident, the engines and propellers were torn down and tested. No evidence of malfunction was discovered in either component.
Investigation Findings
The official investigation identified the following factors related to the collision:
- The aircraft collided with trees during cruise.
- The pilot did not maintain the proper altitude.
- The pilot was experiencing fatigue due to his flight schedule.
- The flight was conducted at night.
- The pilot exercised poor judgment.
Following the initial collision with trees, the aircraft entered an uncontrolled descent and collided with terrain.
Probable Cause
The probable cause, as stated in official findings, comprises two occurrences. Occurrence #1: in-flight collision with an object (trees) during cruise, resulting from the pilot's failure to maintain altitude, fatigue, night conditions, and poor judgment. Occurrence #2: in-flight collision with terrain/water during an uncontrolled descent following the first occurrence.