Page:CAB Accident Report, American Airlines Flight 20.pdf/19

 Investigation of all weather services involved disclosed that the official observational facilities maintained by the United States Weather Bureau functioned in an entirely normal manner throughout the flight. The observers on duty followed the approved procedures at all times and carried out their duties adequately. It further appears that weather reports were broadcast regularly by the radio ranges along the route, including the one at Cincinnati, and that Captain Bryant was thereby apprised of all weather conditions and changes therein along the entire route. In this regard it should be noted that none of the forecasts which were furnished to Captain Bryant prior to departure from Chicago or during his flight to Cincinnati indicated the probability of his encountering storm conditions on arrival at Cincinnati. The United States Weather Bureau airway forecast at 5:30 p.m. predicted the arrival of the warm front at the Fort Wayne-Cincinnati line about 1:30 a.m. the next morning and during the period from 5:30 to 1:30 predicted light rain at Cincinnati with minimum ceilings of 3000 feet. The trip and terminal forecasts furnished Captain Bryant by the company meteorologist indicated light rain throughout the entire trip with ceilings of 2000 feet at Cincinnati on arrival. Both forecasts were based upon the assumption that the fronts in the developing low pressure system shown on the 1:30 p.m. weather map would not reach Cincinnati until after midnight. However, due to an unexpected acceleration of the entire low pressure area, Trip 20 intercepted the extreme apex of an occluding energetic depression about the time it arrived over the Cincinnati airport. At that time the ceiling had dropped to 1300 feet, the visibility was restricted by