Page:CAB Accident Report, Flying Tiger Line Flight 282.pdf/18

 COPY

Mr. George S. Moore Director Flight Standards Service Federal Aviation Agency Washington, D. C. 20553

Dear Mr. Moore:

The Board's investigation of the accident involving Flying Tiger Line Lockheed 1049H, N6915C, at San Francisco, California, on December 24, 1964, indicates a hazardous condition that we wish to bring to your attention together with our recommendations for corrective action.

The Board's investigation of this accident revealed that N6915C made a left turn of approximately 60 degrees shortly after takeoff and flew into a hillside. During this investigation another Flying Tiger L1049H aircraft, N6917C, experienced an error of approximately 30 degrees in its VOR system. All of the major components of the VOR system of N6917C were shop examined and found to be working properly. An internal detailed examination of the Deviation Indicator switch, Lockheed Part Number 319122, revealed many small pieces of wire interspersed among moving parts of the multi-pole switch. These pieces of wire varied in length from 1/16 inch to 1/4 inch and appeared to be ends trimmed off the electrical leads soldered to the terminals. An analysis of possible electrical shorts because of the contamination indicates that navigation bearing angles could be in error as great as 60 degrees. Two other switches of the same type are used on 1049H airplanes of this configuration. These switches are in the ADF and Integrated Flight System.

Although these switches on the aircraft involved in the accident were destroyed by ground fire, a fleet campaign being conducted by Flying Tiger Line has disclosed some contamination on three of six airplanes checked to date.

As a result of these finding it is recommended that the Federal Aviation Agency initiate a fleet campaign of all operators of this type aircraft using this switch to determine whether such contamination exists elsewhere and take such steps as are necessary to eliminate further contamination.

Personnel of our Engineering Division have discussed this problem with Messrs. J. Hemingway of FS-305 and R. W. Thompson of Systems and Equipment Branch, WE-413; J. Long of ACDO, Burbank, California; and T. O'Leary, ACDO, Newark, New Jersey.

If we can be of any further assistance in consideration of this recommendation, feel free to contact us.