Page:CAB Accident Report, United Airlines Flight 21.pdf/81

  of an improved means to prevent the accumulation of ice on wings and other parts of aircraft without thereby interfering with aerodynamic characteristics.

The Board recommends that the Administrator undertake a study of measures that should be adopted at all air carrier airports to keep Airport Control Tower operators, or others responsible for the issuance of information to pilots, informed by reports from the field personnel, pilots or other sources, of hazardous field conditions in order that such information may be promptly relayed to incoming or outgoing pilots.

When the accident happened, the airplane severed power lines leading into the airport, causing discontinuance of the lighting and communication facilities needed to furnish information for the operation of aircraft. The Board recommends that an auxiliary power supply be installed at all airports used by air carriers for instrument or night approaches. The auxiliary power supply should be independent of any source outside the boundaries of the airport and should be applicable to the operation of radio transmitters, field lights and obstruction lights. The Board is considering a requirement to this effect. 

BY THE CIVIL AERONAUTICS BOARD:

/s/ Harllee Branch, Chairman

/s/ G. Grant Mason, Jr., Member

/s/ Oswald Ryan, Member

/s/ George P. Baker, Member

(Edward P. Warner, Vice Chairman, participated in the preparation of this report but was absent from the United States on official duty at the time of its adoption.)