Page:CAB Accident Report, TWA crash on 17 May 1940.pdf/12

 engine was probably sufficient to prevent any further ice formation, but was insufficient to remove any small amount of ice already accumulated. This probably accounts for the fact that No. 2 engine continued to operate with a slight loss of power.

The reduction in power necessitated by the danger of a static discharge from the aircraft to the clouds contributed to a certain degree towards the icing of the carburetors since the lower power reduced the heat available in the rear compartment.

As a result of the investigation of this accident and subsequent flight tests conducted by TWA in cooperation with representatives of the Air Safety Board, Civil Aeronautics Authority, Wright Aeronautical Corporation, and Boeing Aircraft Company, it was decided to provide this airplane with a positive air preheating system through the use of a muff receiving heat from the four upper engine cylinder exhausts. This method provides a temperature rise of at least 100° F.

Aircraft NC 19905, a Boeing 307-B, was certificated as airworthy by the Civil Aeronautics Authority.

Both airmen held required ratings and certificates of competency for the flight and equipment involved.

The flight was a non-scheduled operation and a part of the 100-hour proving for this type aircraft. 