At approximately 3:40 P.M. Central on January 22, 1973, Johnson suffered his final heart attack in his bedroom. He managed to telephone the Secret Service agents on the ranch, who found him still holding the telephone receiver, unconscious and “appear[ing] to be dead”. They attempted resuscitation, and Johnson was airlifted in one of his planes to San Antonio International Airport, en route to Brooke Army Medical Center. However, cardiologist and Army colonel George McGranahan pronounced him dead on arrival at the airport at 4:33 P.M. Johnson was 64.