The nearly 70-year-old airplane had undergone numerous undocumented modifications. The modifications, designed to increase speed, included shortening of the wings, installation of a boil-off cooling system for the engine, increasing the elevator counterweights, modification of the pitch trim system, and changing the incidence of the horizontal and vertical stabilizers.
Although the Federal Aviation Administration required that a flight standards district office be notified in writing of any major changes made to The Galloping Ghost before it could be flown, investigators could find no records that such notifications were made except for the installation of the boil-off cooling system. The undocumented major modifications were identified through wreckage examinations, photographic evidence, and interviews with ground crewmembers