Shortly after the event, Dan Applegate, Director of Product Engineering at Convair, wrote a memo to Convair management pointing out several problems with the door design. McDonnell Douglas had subcontracted design and construction of the DC-10 fuselage to Convair, and Applegate had overseen its development in ways that he felt were reducing the safety of the system. In particular, he noted that the actuator system had been switched from a hydraulic system to an electrical one, which he felt was less safe. He also noted that the floor would be prone to failure if the door was lost, and this would likely sever the control cables, leading to a loss of the aircraft. Finally, he pointed out that this precise failure had already occurred in ground testing in 1970, and he concluded that such an accident was almost certain to occur again in the future.
