Lessons of the 1960s and 1970s
Though the expansion of operational control to supplemental operations enhanced safety significantly, the 1960s and 1970s brought important lessons related to performance planning, weight limitations, and thunderstorm avoidance. Dispatchers influenced all these areas during flight planning and enroute operations. The result of these lessons included safer operations through improved understanding of planning for airplanes that could now fly higher and faster than ever before.
14 CFR Part 121 regulations §121.189 and §121.195 require turbine engine powered airplanes to operate below weights designed to ensure safe operations in the event of an engine failure on takeoff or on approach to landing. Because dispatchers prepare dispatch releases for each flight, they have a direct role in maintaining operational safety through ensuring flights remain in compliance with maximum weight limitations as defined in §121.189 and §121.195. Widespread introduction of much heavier jet transports such as the Boeing 707 and the DC-8 in the early 1960s led to several runway overrun accidents.
Serling (1969) described the problem: "The FAA’s original certification process theoretically required a jet to be able to stop in a certain distance on dry pavements, the distances depending on aircraft landing weight. The FAA itself admitted in 1965 that its requirements were on the unrealistic side…" (p. 151) In 1966, the FAA increased landing distance requirements for wet or icy runways by 15 percent (Serling, 1969, p. 151). Dispatchers began considering the runway condition expected at the time of arrival and planning flights below the maximum weight allowed, accounting for the extra 15 percent of landing distance now required.
The 15 percent increase came into effect too late to save Continental Air Lines flight 12, a Boeing 707 that ran off the end of the runway at Kansas City Downtown Airport on landing on July 1, 1965. The aircraft landed in heavy rain 1,050 feet past the approach end of runway 18. The crew attempted to stop the aircraft but was unable to do so due to the landing gear wheels hydroplaning on the runway. The aircraft slid off the end of the runway and destroyed the ILS localizer antenna building during its slide over a dirt mound, ultimately coming to rest on the airport perimeter road next to a river levee. All sixty-six people on board exited the airplane without major injury (CAB, 1966, p. 1).
Ironically, this accident occurred only six days after the July 7, 1965 publication of the Federal Register contained the FAA’s (1965) new rules requiring the extra 15 percent margin for turbojet airplanes operating to wet or slippery destination runways (p. 8572). In its explanation for the rule changes, the FAA cited ten incidents between 1960 and 1964 involving turbojet aircraft overrunning landing runways. Nine of these ten incidents occurred on wet or slippery runways (FAA, 1965, p. 8570). The FAA concluded that there had not been more overrun accidents because “most of the airports into which the large turbine engine powered airplanes have been operating have runways that are substantially longer…than the minimums required for landing” (FAA, 1965, p. 8570). The Agency worried that the number of turbojet aircraft operations into much smaller airports with shorter runways would result in a significantly higher number of runway overrun accidents. The new rule became effective on January 15, 1966 (FAA, 1965, p. 8570-8572).