- 8 Transformations
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- Johns Hopkins University Press
- pp. 163-176
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CHAPTER EIGHT
Transformations
Congress’s smacking the Civil Aeronautics Administration (CAA) with the budget axe after the air safety hearings was not quite the final act in the bitter debate between advocates of instrument landing system (ILS) and enthusiasts for ground control approach (GCA). After a new series of airline accidents in June 1947, the administration turned the tables on Congress. Truman convened a Presidential Special Board of Inquiry on Air Safety, chaired by John Landis, chairman of the Civil Aeronautics Board. It published an “interim” report in July 1947 that claimed 35 percent of all fatal accidents in 1946 occurred during approach and landing. Congress’ deletion of landing aids from the 1948 budget, the group wrote, guaranteed that “the tragic pattern of the past will inevitably repeat itself.”1 Unless funding for CAA’s landing aids program was restored, the report argued, several more years of unnecessary accidents would occur.
Landis’s report also attacked Congress for its continued belief that ILS and GCA were mutually exclusive competitors, despite the testimony of respected Army Air Force experts that they were, in fact, complementary. The report further undermined Congress’ position by explaining work being done jointly by the AAF, CAA, and the navy at a former navy airfield in Arcata, California, to improve and integrate ILS, GCA, and two other landing aids into a coordinated system to resolve, finally, the blind landing problem. This was, it pointed out “in full accord with the program recommended by the Radio Technical Commission for Aeronautics.”2 The president’s board, in short, implied that the great landing aids debate had entirely missed the point. There was no conflict between AAF and CAA policy. Both sought integration of existing landing aids, not a choice of one over the other, and were doing so through a known, respected, and, above all, politically neutral organization.
Recognition of the need for integration of ILS and GCA derived from serious operational problems that the Army Air Forces, and to a lesser extent CAA, had encountered during World War II. Although both systems were successful as landing aids, that success was circumscribed. They did not solve the blind landing problem. Worse, both proved to have limited capacity. They could be trusted to land aircraft safely as long as the landing rate was kept relatively low, but neither could safely handle high-density traffic.
These two operational problems, then, drove the two agencies to reconsider fundamentally the entire issue of landing aids. They faced two political problems, however, that made it difficult for them to promote an integrated, common system. The partisan conflict between Republican Congress and Democratic administration and the equally fractious conflict between the ILS advocates and the GCA enthusiasts both had to be overcome to get funding restored. To resolve these problems, CAA, AAF, and the navy decided via the Air Coordinating Committee to turn the issue over to a revived Radio Technical Commission on Aeronautics (RTCA), which produced a template for not only a landing aids solution but for a comprehensive, nationwide system of air traffic control. Solving the blind landing problem, ultimately, led to the recognition of a new national-scale problem: airport traffic control.
COMPLEMENTARITY: OPERATIONAL IMPERATIVES
FOR INTEGRATION
During World War II, Army Air Forces leaders had believed that solving the blind landing problem, or even the lesser difficulty of the instrument low approach, would lower their high accident rate and reduce the number of days during which air power was grounded. The Royal Air Force’s Bomber Command did not fly missions if their meteorologists predicted the ceiling over England to be less than 1,000 feet during the return flight, and the Eighth Bomber Command did not fly if the return ceiling was expected to be less than 500 feet.3 This meant that during the war, about half of the missions that had to be scrubbed due to weather were canceled not by weather conditions over the target but over England. That was why physicist David Langmuir had told Lee DuBridge of the MIT Radiation Lab in 1943 that a blind bombing radar could only solve half the weather problem.4 Some sort of landing system had also been necessary to resolve the other half of the bombing halts.
But the 1930s conception of blind landing was insufficient. Even achievement of truly blind landings would not have resolved Eighth Air Force’s weather-related accident problem because of midair collisions during bad-weather operations. Eighth Bomber Command lost hundreds of bombers to accidents during the war, many due to midair collisions.5
The Army Air Forces did not get around to trying to resolve this new problem until early 1945, when it began putting pressure on the MIT Radiation Lab to help it develop a traffic control radar. After brief resistance by the acting director of the Radiation Lab, F. Wheeler Loomis, to becoming involved in a new project so close to the Lab’s expected termination, he agreed to help the Army Air Forces’ Watson Laboratories design a new air traffic control radar based on a heavily modified GCA search radar. This was the CPN-18 project, and George Comstock, who had taken over the GCA project after Luis Alvarez and Lawrence Johnston had fled Cambridge for Los Alamos, was put in charge until the Lab’s closure. The AAF later selected General Electric as the contractor.6
The idea that radar could be used to control aircraft, of course, was not new. The principle was used throughout the war to direct fighters to their targets in a procedure the United States learned from the British, ground controlled intercept. It was also the basis of Alvarez’s GCA system, whose search radar was modified into the new traffic control set. The need for a purpose-designed traffic control radar, in turn, derived from a number of characteristics GCA’s search radar had that substantially reduced its effectiveness for traffic control.
Alvarez’s search radar suffered from several drawbacks. The first was its beam pattern, which topped out at 4,000 feet.7 The radar could not detect aircraft at higher altitudes reliably, and a traffic control radar certainly needed to detect aircraft at normal operating altitudes of more than 10,000 feet. The war had also seen the development of aircraft capable of operating at up to 30,000 feet, and those aircraft were expected to spawn commercial variations immediately after the war. A traffic control radar had to be able to detect all the traffic in an airport’s area if it were to help prevent collisions, and hence it had to scan much higher altitudes effectively.
GCA’s search radar also did not provide its operator with altitude information. Height finding had been left out of the search radar to simplify the equipment and because it was unnecessary to the search radar’s function of directing aircraft into the precision radar’s beams. The accuracy of the barometric altimeter all aircraft had was good enough to get a plane into the precision beams, as long as it could be directed accurately in azimuth and distance. That meant, however, that aircraft at two different altitudes, but the same bearing and range, appeared to the search radar operator as a single aircraft. Further, without altitude information, the radar could not be used for stacking aircraft in holding patterns, which was how aircraft were managed during peak traffic periods. GCA’s search radar could thus be used to separate aircraft by distance but not by altitude, a serious drawback in managing a three-dimensional traffic structure.
The CPN-18 project sought to overcome these major issues, while Glen Gilbert, of CAA’s Air Traffic Control Division, reported on the presence of other problems that perhaps were more important to CAA. After the tests Gilbert ran at Bryan, Texas, in February 1945, he arranged another set of tests at Fort Dix, New Jersey, that May. The objectives were to evaluate the use of radar as a traffic control aid in separating aircraft, and as an aid in providing simultaneous navigation and let-down guidance. Gilbert found that the system had several flaws that had to be fixed to make it truly effective as an air traffic control radar, including elimination of ground clutter and providing aircraft identification. Identification was particularly important to CAA, so that operators could quickly identify aircraft in danger of collisions and issue warnings. Gilbert’s assessment otherwise mirrored the AAF’s, with only the need for aircraft identification on the radar display significantly different.8
CAA administrator Theodore Wright realized that at least for high-traffic airfields, an air traffic control radar might be financially justifiable, and he took steps both to get suitable radars from surplus military stocks and to get a specification written and circulated for a radar designed specifically for the job, based upon Gilbert’s evaluation of GCA. Specification CAA-743, for a commercial air traffic control radar, was the result. The specification was sent to various electronics companies in March 1946, and Gilfillan Brothers, manufacturer of GCA, responded in May. In his letter, the vice president of the company stated that he could not in good conscience submit a bid on a project so similar to the Army Air Forces’ CPN-18. He instead proposed modifying some of the wartime GCA sets to serve until the CPN-18 project reached production in a projected 2.5 years. In his proposed modification the number of radar displays would be reduced to two and placed in a tower instead of in a trailer.9 This was the same modification eventually made to the three AN/MPN-1 sets the AAF loaned to CAA for use at Chicago, La Guardia, and National Airport.
This was the most positive response CAA received to its specification. Other companies submitted bids ranging from $400,000 to $600,000. By comparison, General Electric’s bid on the CPN-18 contract had been $1.1 million. Because its FY1947 research and development budget was much less than these figures, CAA had no money with which to begin a radar program. To ensure that his agency was fiscally positioned to deploy an air traffic control radar once one was developed, Wright requested funds for fifty installations in his FY1948 budget submission to the Bureau of the Budget, but that was cut to twenty-five.10 Radar in any form was not going to reach CAA except as handouts from the wealthier armed services until at least 1949, and the best Wright could do was to take steps to ensure appropriate liaison between the Army Air Forces and his organization in hopes that CAA could influence CPN-18’s development.
The CPN-18 project represented a first attempt to replace the AN/MPN-1 GCA search radar with a purpose-built air traffic control radar, capable of handling the high traffic density of major commercial and military fields even in bad weather. The 1930s version of air traffic control, towers equipped with people wielding binoculars, had been enough to deal with high traffic demands during good weather, but faced with all-weather operations demands by both the AAF and the commercial airlines, the older technique proved thoroughly inadequate. Yet just any old sort of radar would not necessarily function adequately, either. Instead, the AAF and CAA determined that a new radar, based on GCA’s search radar, was required.
While the air traffic control radar was under development, the House of Representatives’ air safety investigation heard from Army Air Forces witnesses on the closely related subject of landing aids. Other witnesses, and most of the questioning, focused on arguments about which of the two landing aids was better, but as the president’s Air Safety Board later pointed out, other testimony argued that question was beside the point. Most of that testimony came from Maj. Gen. Harold McClelland, still the Air Forces Communications Officer, and former brigadier general Milton Arnold, head of the Air Transport Association’s engineering section.
General McClelland, the officer who had requested the Valentine’s Day GCA test in 1943, told the House committee that integration of all useful equipment into a single system was the proper solution to the blind landing problem. McClelland meant that air navigation and control aids had to be considered as parts of a system in order to resolve the operational problems the AAF had encountered during the war. Each individual aid had to be considered in light of its contribution to the whole. Radar was most important for its traffic control uses, while ILS was useful for its easy adaptability to automatic approach and its higher capacity. Since neither ILS nor GCA was a complete approach and landing system in and of itself, the AAF, he told them, was developing two additional parts of an integrated system: runway lights and a British invention called FIDO. McClelland’s testimony was seconded by Milton Arnold, who related his experiences in Europe, before laying out an expansive plan for installing a comprehensive set of approach and landing aids, including the equipment the AAF had under development in its All Weather Flying Program. His proposal ran to $36.65 million for the 160 busiest airports in the United States.11
In late 1944, the Army Air Forces had established the All Weather Flying Program to overcome what was rapidly becoming a greater danger to the AAF than its human enemies, the weather. Originally stationed at Clinton County airfield, near Wilmington, Ohio, the program moved to Lockbourne Army Air Base and then back to Wilmington. The moves hindered it, and it did not achieve a great deal before 1946, when it finally resettled in Wilmington. In early February 1946, Maj. Gen. Curtis Lemay, then head of the Army Air Forces Research and Development Board, called a weeklong conference of both civil and military officials to discuss all available blind flying and landing equipment. At that meeting, the army, navy, and CAA agreed to establish a landing aids experiment station to thoroughly evaluate an integrated set of approach and landing aids under real world conditions. Because the AAF’s All Weather Flying Program operated out of a field with insufficiently poor weather, the Landing Aids Experiment Station was to be established at the former Naval Auxiliary Air Station at Arcata, California, known as the airfield with the worst weather in the forty-eight states. Initially, the navy administered the station while looking for a suitable contractor to run it. A brief contract with the University of Southern California failed in mid-1946, and the navy re-let the contract to United Airlines the same year.12
The Arcata Landing Aids Experiment Station (LAES) was an attempt to overcome the inadequacies of both ILS and GCA. Each was effective for the relatively limited application of dealing with single or very few aircraft. For large numbers, however, neither system was really satisfactory. ILS had no means of coordinating the movement of aircraft around an airfield, and that major deficiency resulted in midair collisions among bomber formations during poor weather. ILS needed a traffic control radar to be effective. Further, with no way to provide positive distance separation between approaching aircraft, planes had to be separated in time. That meant one plane had to land before the next one could be allowed to leave its holding pattern and begin an approach. That reduced the theoretical ILS handling capacity of one aircraft per minute to an actual rate of one every ten to fifteen minutes, depending on the airport.13
GCA had its own problems. As already discussed, the search radar’s capabilities were not adequate to serve as a good traffic control radar. The precision radars, in turn, provided a glide path that was too short for heavy aircraft, and lengthening it meant substantially reducing its handling capacity because the final controller could handle only one aircraft at a time. Lengthening the approach from two miles to ten miles meant the controller had to work with each approaching aircraft for five times as long. Adding operators could increase the capacity, but it also raised the cost. The ILS had no such problem since once on the beam, pilots could fly themselves in. One goal of the Arcata project was, therefore, to develop procedures for using the two systems as complements to each other.
The other major goal was to evaluate two other, nonelectronic systems intended to address the reality that neither ILS nor GCA was an effective blind landing system. Each was an effective approach system, capable of bringing aircraft down to altitudes of 100 feet or so, but although both systems had achieved complete “zero-zero” landings, they could not achieve that safely with every landing. The problem was runway alignment. Both systems could accurately put planes directly above the runway, but could not guarantee that the plane was aligned to go straight down the runway once the wheels touched. Pilots had to verify aircraft alignment visually, which meant operationally that they had to see something outside the cockpit from an altitude of 100–200 feet, depending on the size of the aircraft, in order to achieve alignment before touchdown or to abort the landing.
The two existing systems were FIDO and lights. FIDO was a British development, first put into the RAF Coastal Command base at Davidstowe Moor, the same place Alvarez’s prototype GCA was located under Arthur C. Clarke’s care. It was simply two lines of large oil burners, one down each side of a runway. The idea was to burn off fog, creating an artificial ceiling of 200 feet or so above the runway. FIDO burned approximately 100,000 gallons of fuel oil per hour, making it a very expensive proposition, but it did remove fog from the field. The U.S. Navy installed one at Amchitka, Alaska, during 1944 for tests but found the base too remote for effective testing after the war. At Arcata, FIDO’s fuel consumption was reduced by half by improving the combustion efficiency of the burners, but that still-high expense was compounded by the violent turbulence that the rising heated air generated. Clarke reported that the turbulence was responsible for at least one accident during the wartime British tests. Although large commercial aircraft would be less affected by turbulence than smaller planes, the combination of cost and turbulence made FIDO a commercial failure. One commercial installation was made at Los Angeles in 1949, but no more followed it.14
FIDO would have been an effective emergency landing aid, but commercial aircraft could always go somewhere else less fogbound in the 2.5 percent of the time that ceilings were below 200 feet at a particular field.15 Maintaining an expensive emergency system thus made little sense to the airlines. There was little danger of an expensive crash without FIDO, given the prevalence of alternative airfields in the United States. Passenger discomfort at landing between two walls of flame was no doubt another reason the airlines eventually rejected FIDO.
More controversial than FIDO was the issue of approach and landing lights. Before World War II, both AAF and CAA believed strongly enough in “blind” landings assisted by radio that they simply did not bother investigating the possibility of using lights to improve landing safety. In the late 1930s, the pilots’ union (ALPA) had begun pushing for approach lights of some sort, and CAA had grudgingly begun looking at neon “approach light lanes” to provide some visual guidance, but that program got lost in the war fever. Actual runway lights were not explored at all. During the war, the AAF used an RAF lighting scheme that was nothing more than relatively dim lights around the airfield edges called perimeter lights; these were simply there to inform a pilot that he was over the field. That was the total extent of lighting investigations until wartime experience made it brutally obvious that an appropriate system of lights could make a big difference in helping pilots get that critical bit of visual alignment information before landing.
The president of the pilot’s union fired the first public round in the lighting controversy, which eventually managed to surpass the ILS/GCA controversy in bitterness.16 In a February 1946 editorial, he argued that approach and runway lights should be the first priority of the postwar CAA but was soundly ignored by CAA through 1947. He brought it up again before the House Commerce Committee in his testimony during the air safety hearings and was rewarded with placement of lights at the top of the committee’s own priority list, although lack of agreement over what kind of lights kept Congress from providing funds for large-scale procurement. The basic conflict was over CAA’s intention to install 1,500-foot strips of neon lights in airport approach zones, while the air force, navy, the Air Transport Association and the pilot’s union wanted 3,000-foot strips of high-intensity lights. However, the lights issue did not reach the level of true public controversy until the Arcata project results began to appear in late 1948, perhaps because the aeronautical press could not find a way to make lights as compelling an issue as radar had been.
FAA historian John Wilson deals the lighting controversy in his official history of CAA, and it bears mention here only to report the denouement of the Arcata project. Arcata tests demonstrated the superiority of a runway lighting arrangement called “slope-line lighting” during 1948, after which the air force, navy, CAA, Air Transport Association, and the British and French governments all agreed to it. The pilots union refused to accept it, however, and in a true tour de force, managed to defeat slope-line and get adopted its own center-line lighting system in 1950.17 The pilots union thus humiliated nearly everyone, and in a fit of pique, Congress ordered the Arcata project shut down. The members saw no point in funding experimentation to determine the best methods if the results were simply going to be ignored. Nonetheless, the union got what it wanted over the next several years: the addition of a standardized lighting arrangement at every runway served by an ILS system.
Ultimately, then, the Arcata project had mixed results. Although it was able to reduce FIDO’s voracious fuel appetite and to demonstrate the best lighting configuration, neither of those technical successes translated into widespread use. Nor did the project add to the aviation community’s knowledge of air traffic control issues or of the performance of ILS and GCA under real-world conditions. Both systems had already been thoroughly lab tested, and the Landing Aids Experiment Station was certainly a less realistic operating environment than that available at the many ILS and GCA installations already in operation at commercial and military airfields. It did, however, represent the first integration of the now-common parts of our airport traffic control systems: surveillance radar, ILS, and approach and landing lights.
The aviation agencies that had established Arcata station and its integrated approach to solving the blind landing problem thus had operational reasons for it and CPN-18 traffic control radar projects. The need to speed traffic near congested airports and prevent midair collisions in poor weather was sufficient to justify adoption of expensive installations of the integrated system, at least in high-traffic areas. But the operational considerations that had persuaded the experts had not been persuasive enough to overcome Congress’ predisposition to consider ILS and GCA as competitors, as the outcome of the air safety hearings demonstrates. The aviation community, therefore, had to find a way to overcome the political fallout from the controversy.
POLITICAL IMPERATIVES FOR INTEGRATION
The press attention given to the ILS/GCA controversy during late 1946 and early 1947 had convinced House investigators that CAA and Army Air Forces were pursuing different landing aids, which would impair national defense by making civil airfields unusable by military aircraft. That the two agencies’ plans were not actually incompatible was irrelevant. As long as members of Congress believed that the two agencies disagreed, there existed a political issue that the administration could use against the Republican Congress (as Truman’s Presidential Air Safety Board had done) or Congress could use against the administration (as the House Interstate Commerce Committee had done.) The landing aids controversy thus reached the highest level of politics in the United States. Resolving the 1947 controversy, in turn, meant that CAA and the Army Air Forces, two executive branch agencies, had to convince Congress that they no longer disagreed and that their proposed solution was not merely a political ploy by the administration intended to embarrass Republican congressional leaders. The controversy made integration more difficult to achieve, then, because even if the two agencies agreed on a plan, it was still subject to partisan politics unless some means could be found to present it in a nonpartisan format.
Even if CAA and the army agreed on landing aids, moreover, it was very clear that one group was still strongly opposed to CAA’s plans. Despite the pious claims made by Administrator Wright and the chairman of the Civil Aeronautics Board, John Landis, during their congressional testimony that “all aviation interests” had agreed to CAA’s plans, the controversy revealed that one aviation interest had not been consulted: the Aircraft Owners and Pilots Association. Since AOPA represented private aviation, and private pilots made up the vast majority of all pilots in the United States, it had considerable political suasion among Congressmen interested in ensuring that whatever air navigation system was purchased served the greatest number of people. Hence resolving the ILS/GCA controversy also meant finding some way to appease AOPA and its private pilots, thereby satisfying demands by various members of Congress concerned with pursuing the “greatest good” with taxpayer dollars, and, of course, keeping the votes of tens of thousands of private pilots.
Integration was the obvious solution to both of these political imperatives. Crafting a program that would provide both ILS and GCA services, as well as approach and landing lights, at virtually all airports and many smaller airfields would appease AOPA and its congressional supporters, keep the Pentagon happy, and thereby mollify Congress. Since integration did, in fact, have valid operational imperatives, a plan to deploy air traffic control radars (Airport Surveillance Radars, or ASR, beginning in 1946), ground-controlled approach radars (Precision Approach Radars, or PAR), ILS, and landing lights was defensible from the standpoint of operational need.18 The plan could not be assailed as purely political. The two major potential roadblocks to integration were the cost of the program, which would surely upset fiscal conservatives in both Congress and the parsimonious Bureau of the Budget, and the reality that Republicans in Congress might perceive a plan coming from the Truman administration as an attack on them.
The cost of the program, as one CAA official put it, would have to stand on its own.19 Since public pressure had forced CAA to alter its own program, Wright came to believe that Congress had to be the final arbiter of whether to fund a more expansive, and expensive, infrastructure. One result of the controversy was that after 1947 CAA felt more able to propose an expensive program than its traditional poverty would have allowed.
CAA was then essentially freed of budgetary restraints in its planning by a decision of the Air Coordinating Committee to allow the Radio Technical Commission on Aeronautics to devise the program.20 That decision meant the plan would no longer be the exclusive prerogative of the agency, as the AAF and navy were also represented on the commission, but because this was a nongovernmental committee staffed largely by civilians, it had the freedom to design a system without great concern about cost. This is not to say that cost was no object—the Air Transport Association’s representatives could be counted on to help rein in costs lest airlines be forced to help pay them—but that CAA’s own budget woes could be subordinated to operational imperatives within the commission’s work.
More importantly, however, the Air Coordinating Committee’s decision to rely on the nongovernmental RTCA effectively removed the entire issue from partisan politics. Since RTCA was widely perceived to be a group of experts in an age in which expertise was still considered objective and politically neutral, whatever their product turned out to be would be acceptable to both the Congress and the administration. Indeed it was. Fully published in January 1948, the report of RTCA’s Special Committee 31 was hailed by everyone, immediately adopted by the Congressional Air Policy Committee as its own, and then blessed by the administration, whose own Air Policy Commission published its recommendations too early to jump on the bandwagon.21 To get around the minor problem that RTCA had no authority, the administration then established the Air Navigation Development Board with a mandate to turn the committee’s recommendations into reality.
RTCA’s grand plan did not, however, emerge directly from the Air Coordinating Committee’s decision. Although the agency had been moribund during the war, it had begun meeting in April 1944 to consider how best to make use of all the new radio-based technologies fostered during the war. The original constitution of RTCA’s executive committee, which initially had representatives from AAF, navy, CAA, State Department, ATA, ALPA, Aeronautical Radio, Inc. (ARINC), and the Federal Communications Commission, was altered in early 1946 to add the one major “out” group, AOPA, at that organization’s request. This helped resolve the private flier problem. In December 1945, Delos Rentzel, head of ARINC, submitted an agenda item to the executive committee requesting that RTCA undertake the development of a comprehensive plan to overcome traffic control and air navigation problems.22 His request, in turn, was based on a letter from the Air Transport Association. RTCA’s examination of the problem thus began before the House investigation and the Air Coordinating decision to turn the decision over to them.
Because much of RTCA’s attention during early 1946 was devoted to matters concerning coordination with the new Provisional International Civil Aviation Organization, it did not begin meeting to develop an air navigation plan until August 1946. It produced a brief document that reflected an attempt to grasp the complexities of the new technologies but lacked specificity. It did not detail the amount or cost of equipment needed, and it merely suggested that more research and development needed to be done. Nonetheless, this early report included all of the landing aids that were then being tested at Arcata in its recommendations for “approach zone facilities.” During 1947, RTCA refined its recommendations carefully, to ensure that the program effectively served private, military, and commercial fliers. Largely mirroring the Air Transport Association’s program in its landing aids recommendation, RTCA ultimately recommended an interim target for 1953 of 320 ILS, 150 airport surveillance radar, and 82 precision approach radar installations. It also stipulated that some of the ASR and PAR sets be installed at noncommercial fields so that service was provided to private aviation. In this way, RTCA intended to heal the rift between CAA and the private fliers’ organization. The widespread deployment of precision approach radar that the group proposed also ensured that the radar enthusiasm that the ILS/GCA debate had revealed among the public was addressed, while ILS, already widely deployed, remained to satisfy the pilots union and the airlines’ desire for a system now, not in some Buck Rogers future.23 Finally, this resolved the second political imperative that drove integration. By giving each group the particular technology it favored, RTCA effectively bought their agreement. If no dissenting voices echoed in Congress, the controversy would simply vanish.
RTCA’s proposal, however, was far more than simply a duplication of the Arcata project at every commercial airport and many private flying fields in the nation. In the strong political winds, the commission had taken a long reach and proposed nothing less than the creation of an integrated, nationwide, air navigation and traffic control system. By interlinking (networking, in modern terms) automatic long- and short-range radar, the group envisioned positive radar control over every mile of U.S. airspace. Further, it foresaw the use of automation to eliminate labor-intensive flight progress strips and flight clearance management, allowing automatic tracking of aircraft from takeoff to touchdown, and eventually from gate to gate. It was an ambitious plan expected to take twenty years to complete. It was also a prescription for a very expensive command research and development program, and on the Scylla of cost and the Charybdis of technocracy the plan eventually ran aground.
CONCLUSION
Solving the “blind landing problem” required overcoming unforeseen difficulties that derived from both operational and political imperatives. No one in the 1930s had envisioned that massive increases in traffic would necessitate not only bad-weather landing aids but also robust traffic control aids. The AAF’s experiences during World War II demonstrated that need and further revealed the utter inadequacy of its earlier attempts to beat the weather. By the end of the war, both AAF and CAA realized that more research and development was needed to truly defeat weather constraints on aviation. The operational inadequacies of SCS-51 and AN/MPN-1 meant both systems needed to be supplemented and improved, an imperative the aeronautical press entirely missed. Their different models of operation, pilot control and ground control, proved highly complementary, and their integration into an alliance, albeit an uneasy one, was one foundation of the modern air traffic control system.
The creation of an integrated system of approach and landing aids was not solely driven by operational demands, however. The public frenzy over air safety and radar took the issue out of bureaucrats’ offices and put it before a Congress only too willing to grab it, attack the administration with it, and demand a solution. The dizzying political heights to which the ILS/GCA issue ascended in the United States ensured that the radar versus instrument landing question was at least addressed, even if the answer, SC-31, eventually failed of its promise.
Despite congressional and administration approval of SC-31 and allocation of funds for it beginning in FY1949, the next four years saw the program stall. The Korean War caused the diversion of increasing portions of CAA funding to the Pentagon, weakening its ability to influence Air Navigation Development Board research and essentially eliminating CAA’s airways equipment program, while the election of Dwight Eisenhower installed a president who, as Walter McDougall has argued, resisted the siren call of technocratic management and command research and development. Without strong leadership from the chief executive, the Air Navigation Development Board’s cooperative effort quickly disintegrated into interagency squabbling, and it achieved little. As a result, CAA had a total of ten precision approach radar systems in 1950, and the number never grew larger.24 The ten airport surveillance radar sets it had installed by 1950 also remained unchanged through 1953, and the number of long-range surveillance radars remained fixed at two—both World War II sets on permanent “loan” from the air force—until another air safety crisis caused Congress to dismantle the ineffectual CAA and replace it in 1958. The resulting new agency, the Federal Aviation Agency, was responsible for finally pulling together the postwar technologies of aviation into the modern air traffic system.25