Page:CAB Accident Report, American Airlines Flight 9 (1945).pdf/7

 A showery condition prevailed in the area Roanoke to Chilhowie until after the accident, turning to show about 2000 feet above sea level around 0300 to 0400. Turbulence is believed to have been mostly light but occasionally moderate. There is no reason to believe that much static existed at the 4000-foot level other than that caused by precipitation.

Although the company forecast was used in dispatching the flight the Weather Bureau forecast had been considered. No very important differences were indicated in the two. The following is quoted from the company forecast which was for the period 1900 to 0700, February 22 and 23, 1945:

General:

- 1900-2300 EWT, variable scattered to broken clouds, bases 600 and tops 1200 above sea level, a second layer variable scattered to broken with bases 5000 and tops 7000 above sea level, and a third high broken layer above any intended flight level. Occasional light turbulence in clouds. 2300-0300 EWT, high broken clouds with a lower variable layer scattered to broken with bases 5000 and top 7000 above sea level. Occasional light turbulence below 5000.

- 1900-0200 EWT, high broken clouds with lower variable layer scattered to broken bases 4500 and top 8000 above sea level. Light turbulence to tops of clouds. Light icing in clouds. 0200-0700 EWT, high broken clouds with lower variable layer scattered to broken with bases 3500 and tops 8000 above sea level. Light turbulence to tops of clouds. Light icing in clouds above 5000.

Winds and Temperatures:

Washington - Tri-City - Win 4000 feet 260°, 45 miles per hour; 500 - 250° - 50; 6000 - 250° - 50; 6000 - 250° - 55; 7000 - 240° - 60; 8000 - 240° - 65; 9000 - 240° - 70; 10,000 - 240° - 75.

Temperature 4000 feet 40°F; 5000 - 35°; 6000 - 32°; 8000 - 30°; 10,000 - 35°.

In considering this flight from the meteorological standpoint the most significant factors are summarized as follows:

1. United States Weather Bureau sequence reports available before departure from Washington indicated that continuous CFR (contact flight rules) conditions at 4000 did not exist between Washington and Lynchburg.

2. The company forecast indicated the possibility that continuous CFR conditions would not be found between Washington and Tri-City.

3. The Weather Bureau forecast indicated that continuous CFR conditions at 4000 feet would not be found between Washington and Tri-City.

4. Sequence reports shortly before and at about the time of the accident indicate that continuous at 400 feet were not then existing in the area from Lynchburg to near Tri-City.