United Air Lines Flight 736

The Flight 736 aircraft was a four-engine DC-7 propliner that entered the United Airlines fleet in early 1957, registered as N6328C. On April 21, 1958, it departed Los Angeles International Airport at 7:37a.m. on a scheduled transcontinental flight to New York City, with stopovers in Denver, Kansas City, and Washington, D.C. The flight crew were Captain Duane Mason Ward, age 44, First Officer Arlin Edward Sommers, 36, and Flight Engineer Charles E. Woods, 43. Of the 42 passengers on the flight, seven were military personnel and 35 were civilians. Soon after taking off, the airliner was directed about east through controlled airspace to a waypoint over Ontario, California, where a turn to the northeast towards Las Vegas allowed it to merge with the "Victor 8" airway. The United Airlines crew–using radio call sign "United 7-3-6"–flew the DC-7 under instrument flight rules (IFR), controlled by Civil Aeronautics Authority (CAA) ground stations, at an authorized cruise altitude of 21,000 feet toward the first stopover at Denver. Approximately eight minutes after the DC-7 departed Los Angeles, a U.S. Air Force F-100F-5-NA Super Sabre jet fighter, serial number 56–3755, took off from Nellis Air Force Base near Las Vegas at 7:45a.m. on a training flight with two pilots on board. In the front seat of the tandem cockpit was flight instructor and safety pilot Captain Thomas Norman Coryell, 28. Behind him was his trainee, First Lieutenant Jerald Duane Moran (misnamed Gerald in early reports), 23. As part of his IFR training, Moran would spend the flight under a sliding hood that blocked his view outside the aircraft, but allowed him to see his instrument panel. east of Daggett, California; the report estimated an 8:31a.m. arrival time over McCarran Field near Las Vegas. At 8:28a.m. the F-100F crew requested and received clearance from the military controller at Nellis Air Force Base to begin a procedural "jet penetration" descent to . As the fighter descended in a southerly direction, the airliner was approaching Las Vegas air space at about on a north-northeasterly heading of 23degrees, flying straight and level within the confines of its designated "Victor 8" airway. ==Collision==

radioed by the United Airlines crew was heard at 8:30a.m. plus 20 seconds. The message as recorded by a ground station was "United 736, Mayday, mid-air collision, over Las Vegas." The crippled airliner—now missing about of its right wing—trailed black smoke and flames as it spiraled earthward in an unrecoverable spin. The high aerodynamic forces resulting from the spin exceeded the DC-7's stress limits, causing the engines to be wrenched from their mounts, and seconds later the remainder of the aircraft began breaking apart. The airliner and its associated debris fell onto a then-empty patch of desert outside the town of Arden, in what is now the unincorporated town of Enterprise, about northeast of the estimated collision location. The nearly vertical descent and subsequent explosion made the crash unsurvivable. The fighter jet—its right wing and right tailplane torn away by the collision—left a trail of fragments as it arced steeply downward, rolling as it fell. ==Investigations==

At the request of the local sheriff and United Airlines, the Federal Bureau of Investigation sent fingerprint experts to help identify the human remains. Among the dead were 13 civilian and military managers, engineers and technicians assigned to the American ballistic missile program. Five of that group were civilian contractors attached to the missile program at Norton Air Force Base; they were en route to conferences at the headquarters of the Strategic Air Command at Offutt Air Force Base. Articles in the Las Vegas Review-Journal commemorating the 40th and 50th anniversaries of the crash reported the FBI search went beyond fingerprint matching for identification; the agents were also looking for any surviving sensitive papers relating to national security the group of military contractors had carried on board in handcuffed briefcases. The same reports also said the crash prompted the military and defense industry to adopt rules to keep groups of technical people involved in the same critical project from travelling together on the same plane. The CAB report did not assign blame to either flight crew for the accident, but faulted authorities at the CAA and Nellis Air Force Base for failing to take measures to reduce a known collision exposure; training exercises were allowed to be conducted for more than a year prior to the collision within the confines of several airways, even after numerous near-misses with military jets had been reported by airline crews. The CAB acknowledged that the Air Force, following the accident, took numerous steps to reduce the collision exposure on the airway structure in the Las Vegas area. The report also stated the CAA started a civil-military coordination program, including a review of jet penetrations on a national scale. ==Legacy==

}} (pages 51–52 of 64 in PDF) }} From June 1956 to May 1958—beginning with the high-profile Grand Canyon disaster and concluding with the loss of Capital Airlines Flight 300—in just under two years a total of 245 military and civilian people died in a series of five major United States mid-air collisions involving at least one passenger transport aircraft.{{#tag:ref|Two years prior to the loss of Flight 736, 128 died in the 1956 Grand Canyon mid-air collision between a United Airlines DC-7 and a Trans World Airlines (TWA) Super Constellation airliner. An additional 56 people died during two more major collisions; one in January 1957 near Pacoima, California and one in February 1958 over Norwalk, California. In an editorial published just after the collision, Aviation Week magazine called the loss of Flight 736 "another ghastly exclamation point in the sad story of how the speed and numbers of modern aircraft have badly outrun the mechanical and administrative machinery of air traffic control." The editorial also reminded the reader that a series of Aviation Week editorials in late 1955 warned of the consequences of the failure to take drastic and immediate action. The collision happened at 11:30a.m. Eastern time, and early word about the extent of the disaster spread while the hearing was on a lunch break. Only 15 minutes after the hearing deliberations resumed in the afternoon, the CAB approved—on an experimental basis—an already-discussed proposal barring all aircraft lacking specific clearance from entering specifically set-aside airspace. All aircraft operating in the designated space would have to be equipped for instrument flight operations. The increased speed of aircraft and higher air traffic density made it harder to give pilots enough time to spot each other during flights. Therefore, the CAB said, "it is essential that positive control be extended to altitudes at and on additional routes as rapidly as practical." At the time such control only existed between on certain transcontinental airways. The April28, 1958 issue of Aviation Week reported the CAB admitted it would be "several years, at least" before an all-weather control plan could be implemented, and quoted the head of the CAB's Bureau of Safety as saying the "lack of men, money and machines" stood in the way of implementing a workable control system, nation-wide. Following the loss of the two airliners in the April and May 1958 collisions, a congressional committee from the U.S. House of Representatives—concerned about the lack of coordination between civil and military air traffic controllers—imposed a 60-day deadline on the CAB and the Air Force to establish new control procedures. The FAA was given unprecedented and total authority over the control of American air space, including military activity, and as procedures and air traffic control facilities were modernized, airborne collisions eventually decreased in frequency. Improved air traffic control procedures did not prevent United Airlines from suffering its third mid-air collision in the space of four years—each time with no survivors from the planes involved—when a United Douglas DC-8 jetliner and a TWA Super Constellation propliner collided over New York City in late 1960. In particular, 1958 was the most costly year, with 47 F-100 pilots killed and 116 of the fighters destroyed, a loss rate averaging almost one every three days. ==Legal aftermath==

Following the Flight 736 collision, 48 lawsuits seeking damages—spread across twelve U.S. District Courts—were eventually brought against United Airlines, the U.S. Government, or both. In one lawsuit filed in September 1958, United Air Lines used the Federal Tort Claims Act to seek damages against the United States in the U.S. District Court for the District of Delaware. The airline alleged that the United States through its agents in the United States Air Force negligently operated the F-100. The airline initially sought damages of US$3.57 million, then increased the amount to $3.94 million. The United States filed a counterclaim of $6.19 million. The court eventually found neither crew was negligent for a failure to see and avoid each other, but held the United States was liable because of other negligence. The case was settled in December 1962 when the United States agreed to pay the airline $1.45million. In a judgment in January 1964, surviving relatives of two of the United Airlines crew were awarded a total of $343,200 from the government, with U.S. District Court Judge Olin Hatfield Chilson finding the Air Force pilots did not use "ordinary care" in operation of the fighter jet. Chilson also criticized the Air Force for not coordinating instrument training flights with civilian instrument flight rules traffic, and for failing to schedule flights to minimize traffic congestion. The government appealed, and the relatives cross-appealed to have their damage awards increased, but the earlier 1964 judgment was affirmed in September 1965. ==Crash sites==

The 49 lives lost in this mid-air collision made it the deadliest aviation incident in the history of the Las Vegas region, but the area has experienced two other major airliner crashes. In 1964, 29 people died when Bonanza Air Lines Flight 114 flew into a hilltop SW of the Flight 736 impact site, close to where the F-100F crashed six years earlier. at TWA Flight 3 crash site|alt=Rusted disk-shaped obviously damaged radial engine lying flat on the ground At both of those rugged, mountainous sites, salvage efforts removed the more accessible wreckage, but scattered portions of the TWA Douglas DC-3 and Bonanza Air Lines Fairchild F-27 were left behind, including the DC-3's radial engines. Today the spot where the DC-7 crashed is adjacent to the neighborhood of Southern Highlands near the intersection of Decatur Boulevard and Cactus Avenue, amid commercial development. A small engraved metal cross placed in the sandy soil in 1999 by the son of a victim remained the only sign of the loss of United Airlines Flight 736, but preliminary efforts were in motion to encourage public officials to build a permanent memorial to those who died. A brief video produced by the Las Vegas Review-Journal in April 2018 says the site where Flight 736 impacted is now beneath a parking lot, but the metal cross was still standing nearby on a low hill that remained undeveloped. ==See also==