Braniff regulations prohibited a plane from being dispatched into an area with a solid line of thunderstorms; nonetheless, the company forecast was somewhat inaccurate with respect to the number and intensity of thunderstorms and the intensity of the associated turbulence. Braniff dispatchers were aware that their flight 255 had delayed departing
Sioux City for Omaha by one hour to allow the storm to pass Omaha; they also knew that their flight 234 from
St. Louis to
Des Moines had diverted to Kansas City due to the storm. They did not inform the crew of these events believing they were too far from the route of flight 250 to be relevant. The crew was aware of the severe weather, however, and the first officer suggested that they divert around the activity. The captain instead elected to continue the flight into the edges of the squall line. Dr. Fujita is recognized as the discoverer of
downbursts and
microbursts and also developed the
Fujita scale, which differentiates tornado intensity and links tornado damage with wind speed. Notably, the accident was the first with a U.S.-registered aircraft in which a
cockpit voice recorder (CVR) was used to aid in the investigation. Just before the breakup, the device recorded Captain Pauly instructing First Officer Hilliker to adjust the engine power settings. He was interrupted mid-sentence by buffeting so severe that no more dialog could be discerned on the recording, which continued even after the wings and tail separated from the aircraft. Since the
flight data recorder (FDR) was destroyed in the crash, the changes in the buffeting sound would later be used to estimate the airplane's changes in speed and altitude during the accident sequence. == Aftermath ==