COPY
FEDERAL AVIATION AGENCY
Washington, D. C, 20553
Dear Mr. Chairman:
This is in reference to letters from the Director, Bureau of Safety, Civil, Aeronautics Board, two dated November 30, and one dated December l6, 1965, containing recommendations resulting from your investigation of the United Air Lines, Boeing Model 727 accident at Salt Lake City, Utah, on November 11, 1965. These were acknowledged respectively, on December 8, 10, and 27, 1965. We have studied your recommendations and are pleased to report that we have had many of them under consideration for some time. As you know, the details of many of the points will take time and resources to fully reconcile, but will be resolved as soon as possible.
The Agency safety program relative to the areas mentioned in your letters is outlined below:
Fuel lines and generator leads
Concerning your recommendation to relocate the fuel lines in the Boeing 727 near the centerline of the aircraft, our evaluation of this indicates the present location is the best possible because the lines are surrounded by the heaviest structure available in their present locations. If the fuel lines are moved inboard toward the center of the airplane, they will then be susceptible to rupture by items in the cargo compartment in the event of a belly landing which is the more conventional type of damage anticipated in emergency landings. We note in the Salt Lake City accident that the bottom of the fuselage was crushed upward approximately 20 inches. It is for this reason that the fuel lines were initially located in their present position. It is recognized that the fuel lines can be strengthened and their resistance to impact or shearing type failures can be improved. Engineering design studies are now in process to develop such improved type lines on a retrofit basis.
In regard to your recommendation to use stainless steel lines and shrouds, the redesigned configuration being studied is expected to include a neoprene core, stainless steel sheathing, and a teflon-type covering The aluminum alloy shrouding will be retained since it is less prone to cutting or shearing of the fuel lines.
