Background
At 0515 EST, a flight was cleared for takeoff from Ypsilanti, Michigan, bound for Louisville, Kentucky.
Flight History
Approximately 17 minutes after departure, the flight crew began to display indications of a deterioration of their ability to control the aircraft. Initially, they deviated from instruments and held west of the Findlay VOR at FL220. As the flight continued and was cleared to FL270, the crew displayed confusion about magnetic headings and basic instruments.
Final Moments
At 1048 EST, the aircraft deviated from the en route heading, and a wrong heading was read back after a heading correction was given. The aircraft continued climbing to FL291. Radar and radio contact were lost at 0551 EST. The controller noted the pilot's speech was slurred and some portions of the conversation were unintelligible. Subsequently, the aircraft crashed in a steep dive.
Aftermath
No preimpact part failure was verified, though impact forces and post-crash fire resulted in extensive damage to the aircraft. The aircraft was equipped with an oxygen and pressurization system. No audible warning was noted on ATC recordings to indicate the cabin altitude had exceeded 10,000 feet, though the aircraft was equipped with such a device. Both pilots were killed.
Probable Cause
The flight crew became incapacitated for undetermined reasons and lost control of the airplane.