What happened
During a cruise flight at 27,000 feet, the windshield of a Beech King Air 200 began to fracture. At the time of the fracture, the company pilot was in the cabin and not at the controls, leaving a noncompany pilot—who had not completed training or a checkout for this specific aircraft type—alone in the cockpit. Although the windshield remained structurally intact, the pilot chose to depressurize the aircraft due to concerns regarding the glass integrity.
Following the depressurization, the crew attempted to utilize oxygen masks but were unable to access oxygen. While the oxygen system was functional, the pilot had intentionally turned the oxygen system ready switch to the OFF position during preflight to conserve supply, deviating from the approved flight manual. This lack of oxygen likely led to the crew losing consciousness.
Following the loss of consciousness, the aircraft entered an uncontrolled descent. Radar data indicated the plane dropped from 25,400 feet to 7,800 feet over a five-minute period. During this time, the cockpit voice recorder captured engine propeller noise and various warning horns. The crew eventually regained consciousness and recovered the aircraft, though the Beech King Air 200 sustained substantial damage from the forces of the descent.
Findings
- The pilot relied on an unapproved checklist document that lacked instructions for handling a fractured windshield and did not include the requirement to keep the oxygen system on.
- The pilot demonstrated poor judgment by intentionally depressurizing the aircraft, despite the flight manual stating that the plane could safely fly for up to 25 hours with a fractured windshield.
- The pilot's decision to turn the oxygen system to the OFF position during preflight directly contributed to the crew's inability to breathe during the emergency.
- The initial windshield fracture was caused by a design deficiency in the glass, which the manufacturer later corrected in 2001.