 The CAB found evidence to believe that hydroplaning had occurred due to water accumulation on the runway.Based on information from Boeing on the 707's braking performance, input from a NASA technical expert, and witness interviews, the CAB determined that under the landing conditions at the time, it was not possible for Flight 12 to come to a stop in the remaining distance.In June 1966, the CAB released their final report, concluding that "the probable cause of this accident was hydroplaning of the landing gear wheels which precluded braking effectiveness."