Page:CAB Accident Report, United Air Lines Flight 823.pdf/5

 All the propeller blades had the same TSO as their hubs. The TT on the blades of Nos. 3 and 4 propellers were identical with their hubs but the total time of the blades on No. 1 propeller was 15,312:58 and on No. 2 the propeller was 20,376:28.

A review of the maintenance records revealed there were no known discrepancies when the aircraft left Washington. The records indicated that N7405 was maintained in accordance with existing United Air Lines, Inc., and FAA approved directives with the exception of the deletion of a turbine blade inspection of No. 2 engine during the last block overhaul, and a similar deletion of an inter-cooler air inlet cleaning operation. The aircraft and powerplants were reported to be airworthy at the time of departure from Washington.

The takeoff weight of Flight 823 was 58,948 pounds and the weight was estimated to be 51,468 pounds at the time of the crash. Maximum allowable takeoff weight for runway 33 at Washington National Airport was 60,600 pounds. The center of gravity (c.g.) limits for the flight were 9 percent Standard Mean Chord (SMC) forward and 26 percent SMC aft. The aircraft was within these limits at takeoff and was computed to be within limits at the time of the crash.

The aircraft was loaded with 10,900 pounds of Jet A at takeoff and was computed to have 6,327 pounds of fuel aboard at the time of the crash.

1.7

The United States Weather Bureau (USWB), Washington Office, issued an aviation area forecast at 1345 valid for 12 hours beginning at 1400, which included Washington D. C., eastern North Carolina, and Virginia. A trough was reported extending southwestward from a low off the New Jersey coast. Throughout the area clouds were forecast at 3,000 feet scattered variable to broken; ceilings 10,000 feet broken variable to overcast; scattered ceilings of 1,500 feet broken, 5,000 overcast; visibility two miles in light rain, showers, or thunderstorms with light rain showers; becoming 3,000 feet scattered, ceilings of 12,000 broken and eight miles visibility by 2200. Thunderstorms were forecast to be more numerous in West Virginia through western Virginia and western North Carolina. The freezing level was forecast to be 11,000 to 12,000 feet with brief moderate, possibly heavy icing above the freezing level in heavy showers and thunderstorms. Brief severe turbulence was forecast to be likely in thunderstorms.

The USWB office at Memphis forecast squall line thunderstorms over western Tennessee from 1500 to 2100. Central and eastern Tennessee were forecast to have ceilings at 2,000 to 3,000 feet broken, variable to scattered, 10,000 overcast variable to broken with layers merging and tops to 40,000 feet and, in scattered thunderstorms and heavy rain showers, ceiling 500 feet overcast, visibility one mile. Heavy mixed icing was forecast in thunderstorms above the freezing level at 12,000 to 13,500 feet.

The Knoxville terminal forecast issued by USWB Memphis at 1145 valid for 12 hours beginning at 1200 called for scattered clouds at 3,000 and 30,000 feet with a chance of a thundershower.