Accident Summary

On November 11, 1965, United Airlines Flight 266, a Boeing 727, crashed during an attempted landing at Salt Lake City Airport (KSLC). The captain failed to take timely action to arrest an excessive descent rate during final approach. After touching down 335 feet short of the runway, the main landing gear sheared off and the airplane caught fire. The airplane then slid 2,800 feet on the nose gear and the bottom of the fuselage, stopping 150 feet off the right side of the runway.

Severe upward and rearward impact forces from the right main landing gear assembly produced a large impact hole and ruptured fuel lines and the No. 3 generator leads on the right side of the fuselage. The fuel was ignited by sparks from the fuselage scraping on the runway and/or the severed generator leads. The hole and fire damage area extended circumferentially from the lower sill of the aft cargo compartment door to the tip of the fuselage. The entire roof and cabin area forward of this was consumed by fire which was initially being supplied fuel under pressure by the operating boost pumps. All flight control cables, fuel supply lines from the Nos. 2 and 3 tanks, and the No. 3 generator leads which were routed through the cabin floor beams in the area of the impact hole were consumed by fire. Only a 5/8 inch stainless steel hydraulic pressure line remained intact. Of the 85 passengers aboard, there were 43 fatalities. All 6 crew members survived.

The certification basis for the Boeing 727 included FAR 25.721 at Amendment 0. That rule required landing gear to meet certain shock absorption, limit drop test, and reserve energy absorption drop test standards. As a result of the United 266 accident, FAR 25.721 was modified at Amendment 15 to include a requirement to consider the puncture hazard posed to the fuel system, in the event of a landing gear failure due to overloads during takeoff and landing.

The Civil Aeronautics Board (CAB) determined that the accident was survivable - none of the passengers sustained any traumatic injuries that would have precluded their escape. The 43 fatalities were attributed to the fire caused by the broken fuel line. The CAB also established that similar future events could not be ruled out, and that the airplane should be designed to have a higher degree of survivability in these types of events.

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