chairman Alan S. Boyd told reporters shortly after the accident, "It was so compacted there is no way to tell at this time whether we can derive any useful information from it." Eventually, investigators were able to extract data from 95% of the tape that had been in the recorder. The recovery of the wreckage took place over a period of 12 days, and 16 truckloads of the debris were taken to Bolling Air Force Base in Washington, DC, for investigators to examine and reassemble. Investigators revealed that a fire had occurred in flight, and one commented that it was nearly certain that an in-flight explosion of some kind had occurred. Eyewitness testimony later confirmed that the plane had been burning on its way down to the crash site. Within days, investigators reported that the crash had apparently been caused by an explosion that had blown off one of the wing tips. The wing tip had been found about from the crash site bearing burn marks and bulging from an apparent internal explosive force. Remnants of of the wing tip had been found at various points along the flight path short of the impact crater. Investigators revealed that rough turbulence was unlikely to have caused the crash because the crews of other aircraft that had been circling in the area reported that the air was relatively smooth at the time. They also said that the plane would have had to dive a considerable distance before aerodynamic forces would have caused it to break up and explode, but the aircraft apparently had caught fire close to its cruising altitude of 5,000 feet. Before this flight, lightning had not been known to cause a plane to crash, despite many instances of planes being struck. Typically, an airplane is struck by lightning once or twice a year in normal operations. Scientists and airline industry representatives vigorously disputed the theory that lightning could have caused the aircraft to explode, calling it improbable. The closest example of such an instance occurred near Milan, Italy in June 1959, when a Lockheed L-1049 Super Constellation crashed as a result of static electricity igniting fuel vapor emanating from the fuel vents. Despite the opposition, investigators found multiple lightning strike marks on the left wing tip, and a large area of damage that extended along the rear edge of the wing, leading investigators to conclude that lightning was indeed