IRVING R. KAUFMAN, Chief Judge:

Four days after oral argument of this case, the President of the United States decided to permit supersonic transport aircraft service to thirteen American cities under specified restrictions. The President's decision followed sixteen months of demonstration flights at Dulles International Airport in Virginia by the Anglo-French Concorde, during which the noise and vibration levels of the aircraft were carefully monitored. A similar test at New York's John F. Kennedy International Airport, requested by the Secretary of Transportation and which the President "continues to support . . . pending a decision on the final (federal) noise rule," has yet to commence because the airport's proprietor, the Port Authority of New York and New Jersey, refuses to promulgate an acceptable noise rule for supersonic aircraft. Our sole task is to determine the legality of the total ban, which has now endured for more than one and one-half years, imposed by the Port Authority on Concorde flights into Kennedy pending an alleged effort to develop a noise standard.

This case, of course, is no stranger to our court. More than three months ago, after a careful review, we held that the Port Authority possessed the power and bore the responsibility to establish fair, even-handed and nondiscriminatory regulations designed to abate the effect of airplane noise on surrounding communities. British Airways v. Port Authority, 558 F.2d 75 (2d Cir. 1977) ("Concorde I"). We urged in that opinion that the Port Authority conclude its study and fix reasonable noise standards "with dispatch", for it was apparent that procrastination would only exacerbate the economic injury already suffered by the airlines, hinder legitimate efforts to determine the technological and commercial feasibility of supersonic aviation and further strain our foreign relations. We also directed Judge Pollack to conduct an evidentiary hearing to determine whether the Port Authority's then 13 month delay in promulgating noise regulations applicable to supersonic aircraft was so excessive as to constitute unfair discrimination and an undue burden on commerce.

It was our intention, in deciding as we did, to give the Port Authority another opportunity to come to grips with the problems posed by this clash of opposing forces. We hoped it would resolve the strife being generated by this litigation by, at the least, deciding to promulgate a noise rule equally applicable to all planes landing at Kennedy, without the court's intervention on the details of the Rule.

To this day the Port Authority has demonstrated total resistance in responding to the airlines' desire to secure a fair test of their aircraft in New York. Moreover, it is plain from its public statements that the Authority has no intention to resolve this critical issue in the foreseeable future. We cannot countenance such abdication. Accordingly, we will affirm the order of the district court, enjoining further prohibition of Concorde operations at Kennedy Airport until the Port Authority promulgates a reasonable, nonarbitrary and nondiscriminatory noise regulation that all aircraft are afforded an equal opportunity to meet. We have also found it necessary, however, to modify Judge Pollack's order as hereafter indicated.

I. FACTS

The Port Authority's 112 PNdB Noise Rule. The onslaught of civil jet aviation after World War II sorely tested our nation's commitment to make technological progress environmentally acceptable. As the proprietor of two airports in America's most populous city, the Port Authority of New York and New Jersey was thrust at an early date into the forefront of efforts to accommodate the needs of commercial aviation with the understandable desire of airport neighbors to enjoy a reasonable degree of peace and tranquility. Thus, in 1951 the Authority adopted a regulation prohibiting use of any of its facilities without permission. This rule vividly demonstrated the Port Authority's determination to compel the manufacture of quieter aircraft, a desire which was soon underscored by its refusal to accord landing rights to certain jet airplanes whose din was deemed intolerable to surrounding communities.

Both the vital importance of the aviation industry to the national economy and basic considerations of fairness, however, required that even the appearance of whim and caprice be eliminated from critical decisions concerning airport access. The Port Authority accordingly retained a consulting firm in 1955, and charged it with developing a method of meaningful quantification of the relative reactions of individuals to the quite different character of noise produced by existing propeller driven aircraft and newer jet engines. By 1958 it was demonstrated that an ordinary person heard 112 PNdB (perceived noise in decibels) emitted by a jet as substantially equivalent to the sound produced by a DC-6B piston airplane. The Port Authority therefore adopted 112 PNdB, as registered at selected monitoring points, to be the maximum permissible noise limit for all aircraft wishing to use John F. Kennedy International Airport.

The Port Authority's noise standard, of course, was not intended to transform Jamaica Bay and environs into a sylvan glen. By requiring only that the next generation of civil aircraft be no louder than its noisiest predecessor, the Authority sought a standard which it believed would prevent further deterioration of the area surrounding JFK. The aircraft industry was assured that any plane able to meet the standard, either through quieter engines or noise abating operating procedures, would be welcome in New York. In fact, until the Port Authority imposed the ban on supersonic aircraft that is challenged in the instant suit, not a single jet airplane that met the long-standing 112 PNdB rule was denied access to Kennedy Airport.

SST Noise. Since New York is this country's most important international gateway, it is not surprising that the manufacturers of the Concorde, the world's first supersonic commercial passenger airplane, communicated their desire to use JFK to the Port Authority more than seven years ago. At that time John R. Wiley, the Authority's Director of Aviation, warned that SSTs would "be required to meet the same noise levels as will be demanded of subsonic aircraft." In fact, those who built the Concorde were well aware that its noise posed a serious objection to American acceptance of the plane. Accordingly, the French and British spent nearly $100 million on noise abatement alone.

Before requesting specific permission to use Kennedy Airport, the owners of Concorde compiled reams of data concerning the likely effects of its noise on airport neighbors. In a series of tests conducted in late 1974 at Casablanca, Morocco and Toulouse, France, the manufacturers of the aircraft proved — in conditions closely simulating those at JFK — that the Concorde could consistently meet a 109 PNdB standard. Indeed, it was reported that the "Boeing 707 under [its] flight path [had] a distinctly greater spectral content in the more annoying frequency range bands, compared with Concorde." Moreover, the incremental impact of adding several Concorde flights to an already busy airport was found to be minimal. And further testing in January, 1976 demonstrated that even fewer individuals than originally anticipated would be adversely affected by the introduction of Concorde at JFK.

Federal Action. In late summer 1975 British Airways and Air France, confident of their aircraft's ability to satisfy applicable regulations, applied to the Federal Aviation Administration for permission to use the SST in transatlantic service to the United States. A thorough Environmental Impact Statement was prepared, and formed the basis for Secretary of Transportation William T. Coleman's careful and comprehensive decision of February 4, 1976, to order provisional amendment of the airlines' operations specifications to permit each carrier to conduct up to two flights daily into Kennedy and one per day into Dulles International Airport. This grant was accompanied by stringent conditions. For example, the Concorde could not travel at supersonic speeds over land areas; it had to observe a 10 P.M. to 7 A.M. curfew; and the aircraft was directed to abide by strict noise abatement procedures as prescribed by the F.A.A. In addition, these amendments were not to be effective beyond sixteen months from the commencement of commercial service. Finally, Secretary Coleman explicitly provided that all flights would cease immediately "in the event of an emergency deemed harmful to the health, welfare or safety of the American people."

Before rendering his decision, which we have termed "the very paragon of a clear and considered administrative action", Concorde I, supra at 80, Secretary Coleman painstakingly discussed both the traditionally recognized component of Concorde noise (addressed by the Port Authority's 112 PNdB rule) and its purportedly unique capacity to emit substantial low frequency vibrations. Based on his review of voluminous data, Coleman concluded that the noise of a Concorde at its source was indeed louder than that produced by subsonic aircraft under similar conditions. But this revelation was only the beginning of analysis, for relevant regulations are carefully calculated to reflect the relative subjective impact of aircraft noise on individuals living in the vicinity of airports. In fact, to focus upon the absolute energy emission levels of Concorde's engines without considering the mitigating effect of noise abatement procedures — as the amicus curiae does in this case — is as empty an exercise as inquiring of a Kantian philosopher whether a tree falling in a deserted forest can be "heard."

Coleman thus turned for guidance to a federally prepared Noise Exposure Forecast (NEF), which described the cumulative effect of all aircraft operating at JFK within the course of 24 hours. This index, which included corrections for the discrete whine of certain jet aircraft and penalized flights scheduled during normal sleeping hours, revealed that the addition of eight Concorde flights a day would produce only a negligible impact on the communities surrounding JFK. More specifically, the descriptor indicated that the number of people residing within the NEF 30 contour — a term of art applying to those instances in which certain individuals "may complain" — would increase by only 0.4%, from 485,000 to 487,000; and within the NEF 40 zone — in which "repeated vigorous" complaints would be forthcoming — from 112,000 to 114,000, or by 2%. Overall noise in each contour would increase by about 0.3%. Although this meant that a greater number of people would be subjected to a somewhat noisier environment, the Secretary cogently noted that an identical effect would be created (without amending any operating certificates) simply by the addition of "a few extra flights by . . . B-707's or DC-8's."

Secretary Coleman also recognized that the sound produced by the Concorde's engines is of a relatively low pitch and thus qualitatively different from that emitted by subsonic aircraft. The plane's deep rumble, he said, would cause minor structural shaking; and the fact that its sound readily penetrates buildings would result in the rattling of dishes and other non-stationary objects within homes. Coleman concluded, however, after a comprehensive survey of the evidence, that "these vibrations do not present any danger of structural damage and little possibility of annoyance." In fact, under the strictly limited regime contemplated in his order, the Secretary was confident that the resulting irritation would be slight, and the Concorde induced vibrations "brief and barely perceptible."

In the end, Coleman recognized that a testing period of actual Concorde operations was an essential prelude both to the final decision on the aircraft's acceptability in the United States and to the determination whether public hostility in America's premier commercial center made the development of a second, quieter generation of SSTs economically unfeasible. Raw data alone cannot forecast community response to SSTs, for every individual reacts differently to noise. The sixteen-month demonstration ordered by Coleman was thus a crucible in which to assay subjective attitudes of airport neighbors and our willingness to fairly assess the issue of supersonic transportation. In the words of this court, "the very dimensions of the most significant environmental drawback of the Concorde are impossible to determine without an adequate test." Concorde I, supra, at 80.

The Port Authority's Response. While technicians strove to project scientifically the community response to Concorde noise, local leaders on the political scene lobbied to prevent SST landings at Kennedy. On January 5, 1976 New York State Commissioner of Transportation Raymond Schuler conveyed Governor Carey's unqualified opposition to Concorde to Secretary Coleman at a public hearing; he testified to the same effect six weeks later before the Port Authority's Operations Committee. The New York Legislature simultaneously passed a bill banning all SSTs from Kennedy Airport. Although we do not know the impact of these actions of the Commissioners of the Port Authority, who are appointed by the Governors of New York and New Jersey, soon thereafter — on March 11, 1976 — the Concorde was banned by the Authority from JFK for a period not to exceed six months, during which operations at Dulles, Charles de Gaulle and Heathrow Airports were to be monitored and analyzed.

In taking this action, the Port Authority did not apply its existing and well-established 112 PNdB rule to the Concorde. Rather, it suggested that the unique low frequency vibrations produced by the SST's engines "were not necessarily reflected" in the current noise standard. Although Secretary Coleman found the adverse environmental effects of the Concorde's low pitched sound to be negligible, the Port Authority concluded the issue warranted further study. And while the Authority agreed with the Secretary that the subjective reaction of people exposed to SST noise needed further inquiry under actual operating conditions, it questioned whether such testing at JFK was in the "public interest."

The Authority also believed it was necessary to retain consultants who would further study the SST and quantify the vibration problem in a manner that would accurately predict community reaction to this unique component of the SST's noise profile. Accordingly, on May 24, 1976 — the day that flights began in Washington, D.C. and more than three months after Coleman's exhaustive decision — the Port Authority engaged Dr. Karl Kryter of the Stanford Research Institute to examine Concorde noise.

Dr. Kryter spent several months recording onto magnetic tape the noise of all types of aircraft, including the Concorde, at JFK, Dulles, Charles de Gaulle and Heathrow Airports. By February, 1977 he had developed a formula that, in his words, "would allow one to a first order of approximation [to] say that if you had the 707 and the Concorde in a given mode of operation with a given level of noises commonly measured, what the relative difference in potential vibration would be. "The critical importance of this research cannot be gainsaid, for it demonstrates that eight months ago the Port Authority's principal consultant had devised a means of relating household vibration to the SST's absolute noise levels, a "vibration-rattle index." What Kryter had not been able to do was correlate this figure with the amount of irritation an individual would experience at a given level of noise and vibration.

When Dr. Kryter reported these results to the Port Authority in early March, 1977, he was asked to outline a proposal for solving this elusive problem of "additivity." But the Authority has never actually engaged Kryter, or anyone else, to pursue such research. Moreover, he has testified that an additivity study would consume six months to a year, and cost between $500,000 and $1 million. The Port Authority refused to embark upon such an expedition, and has not authorized a single penny to be spent on its completion. Neither, of course, does it wish to assay subjective reaction to vibration through actual test flights, as Secretary Coleman suggested. Thus it is not at all clear to us how the Port Authority intends to solve this additivity dilemma, if indeed it ever expects or wants to do so.

Airlines Submit Revised Operating Procedures. While the Port Authority found that the problems of Concorde noise were either intractable or capable of logarithmic expansion, the airlines continued to refine existing data that proved Concorde's ability to meet the longstanding 112 PNdB standard at JFK. Thus, by telex on March 7, 1977 the owners of Concorde detailed certain revised procedures entailing reduced operating weights, specific runway utilization assuring that 98% of departures would occur over water, and a "decelerated approach" making it graphically apparent that the Concorde's noise would not exceed 105 PNdB at any Port Authority meter. In addition, it was against established that the incremental disturbance of individuals within the NEF 30 and 40 contours would be negligible. On April 14 the F.A.A. confirmed the technical validity of the airlines' newest submission. It was now clear not only that the Concorde met the established 112 PNdB rule, but also that its perceived noise "footprint" was comparable to that of the B707-320B.

The Port Authority's Response. Although the Port Authority originally had banned the Concorde from JFK for a period not to exceed six months, the agency ultimately established March 10, 1977 — a full year after its initial resolution — as the date it would render a definitive decision on this important issue. In the period of more than a year since Secretary Coleman's decision, a wealth of new data had been complied to aid the Authority in its task, including monthly progress reports on SST operations at Dulles. All consultants had completed their work and reported their conclusions, and the Port Authority had decided not to authorize any further funding for efforts to quantify Concorde noise. The Commissioners nevertheless answered the airlines' latest initiative by postponing consideration of Concorde landings from March 10 to "a later date." An accompanying press release claimed this course was chosen out of "fairness" to the airlines, implying that they had proved for the first time their aircraft's capability to meet the 112 PNdB rule. But in fact, from the first tests in 1974, there had never been a shred of evidence indicating the SST's inability to meet the rule, and the March 7 submission merely proved the Concorde even quieter than theretofore supposed. In this context it is not surprising that the airlines immediately notified the Port Authority that "our patience has run out," and sought relief in federal court.

Litigation, Round 1. On May 11, 1977 Judge Pollack dissolved the Port Authority's ban on Concorde, reasoning that Secretary Coleman's decision to accord the plane limited permission to land in this country preempted any contrary exercise of local authority. British Airways v. Port Authority, 431 F.Supp. 1216 (S.D.N.Y. 1977). This court, with the concurrence of the government as amicus, reversed. We held that federal law contemplated a limited role for airport proprietors. We decided that their task was to promulgate reasonable rules to abate noise in the airport and its environs. We also remanded for an evidentiary hearing to ascertain whether the Port Authority had exercised its responsibility in a "fair, reasonable and nondiscriminatory manner" or whether, as urged by the airlines and the United States, the thirteen month delay — as it was then — in promulgating a uniform noise standard for the Concorde was unreasonable, discriminatory and hence illegal.

The Port Authority's Response. Five days before the mandated hearing, on July 7, 1977, the Port Authority's Commissioners voted to indefinitely extend the "temporary" ban imposed sixteen months earlier. The Authority merely reiterated what had been known for years — that the Concorde had "unique characteristics including that on landing [it] has a high level of low frequency energy." Despite the receipt of monthly progress reports from Dulles since the inception of service there, the Authority had now grasped another excuse for non-action: it would await a final federal compilation of Concorde data, due in late September. This is puzzling, of course, in light of the Port Authority's repeated disavowal of earlier federal studies favorable to the SST, and its assertion of complete independence in conducting its own examination of Concorde noise. And even more perplexing, since the work of its consultants had ceased four months earlier, was the Authority's statement that a "vibration-rattle index is being further studied."

Judge Pollack's Decision. On August 17, the district judge again struck down the Port Authority's ban of SST flights after concluding that for over a year the agency had been "reploughing old ground and doing re-reviews of scientific and theoretical data previously available." In the view of the district court Dr. Kryter had established nothing beyond what was adequately considered and reported by Secretary Coleman, and the Port Authority had no intention of setting either 112 PNdB or any other noise standard for the Concorde. This total abdication constituted an unreasonable, discriminatory and unfair impingement on commerce. The Port Authority, accordingly, was enjoined from prohibiting further SST flights into JFK if they emitted no more noise than 112 PNdB.

Ensuing Action. Neither advocates nor opponents of the Concorde have declared a truce while awaiting our review of the district judge's order. Recently several members of Congress urged that the federal government restudy low frequency vibrations. But, on September 15, 1977 Secretary of Transportation Brock Adams, in separate letters to Elmer Staats, Comptroller of the Currency, and Port Authority Director of Aviation Morris Sloane, declared that it was "unnecessary to define and quantify a vibration-rattle index before initiating regulatory action on new noise standards." In fact, Secretary Adams reported, the vibrations emitted by the SST were no greater than those induced by long range subsonic aircraft, such as the B-747 and DC-10. And since these aircraft have been flying into JFK for several years without apparent rattle problems, the Secretary believed increased structural damage and annoyance to be "improbable." Indeed, the Dulles demonstration, Adams stated, had shown that vibration levels were even less than originally anticipated. Dr. Kryter's report, in the opinion of the Department of Transportation, had not raised any new questions, and the existing data was sufficient to justify the inception of public notice and comment procedures for certification of the Concorde without further delay. This course was followed eight days later when President Carter decided to permit existing Concordes to fly into thirteen American cities, including New York, without requesting further vibration research.

II. DISCUSSION

The law simply will not tolerate the denial of rights by unwarranted official inaction. Cf. NLRB v. Rutter-Rex Mfg. Co., 396 U.S. 258, 265-66, 90 S.Ct. 417, 24 L.Ed.2d 405 (1969); Nader v. FCC, 172 U.S. App.D.C. 1, 520 F.2d 182 (1975). If ever there was a case in which a major technological advance was in imminent danger of being studied into obsolescence, this is it. There comes a time when relegating the solution of an issue to the indefinite future can so sap petitioners of hope and resources that a failure to resolve the issue within a reasonable period is tantamount to refusing to address it at all. The same is true of studying the question in such a manner that the issue will disappear by sheer frustration or the assumption by another institution — in this case the courts — of the task of deciding a charged dispute whose resolution otherwise is the duty of the agency. The hour is at hand for the Port Authority's indefinite ban on Concorde flights to be recognized as an abdication of responsibility. The airlines should no longer be forced to suffer the consequences of such illegal delay.

Our initial opinion in this case delineated the extremely limited role Congress had reserved for airport proprietors in our system of aviation management. Common sense, of course, required that exclusive control of airspace allocation be concentrated at the national level, and communities were therefore preempted from attempting to regulate planes in flight. See Allegheny Airlines v. Village of Cedarhurst, 238 F.2d 812 (2d Cir. 1958); American Airlines v. Town of Hempstead, 398 F.2d 369 (2d Cir.), cert. denied 393 U.S. 1017, 89 S.Ct. 620, 21 L.Ed.2d 561 (1969). The task of protecting the local population from airport noise, however, has fallen to the agency, usually of local government, that owns and operates the airfield. Air Transport Assn. v. Crotti, 389 F.Supp. 58 (N.D.Cal. 1975) (three-judge court); National Aviation v. City of Hayward, 418 F.Supp. 417 (N.D.Cal. 1976). It seemed fair to assume that the proprietor's intimate knowledge of local conditions, as well as his ability to acquire property and air easements and assure compatible land use, cf. Griggs v. Allegheny County, 369 U.S. 84, 82 S.Ct. 531, 7 L.Ed. 585 (1962), would result in a rational weighing of the costs and benefits of proposed service. Congress has consistently reaffirmed its commitment to this two-tiered scheme, and both the Supreme Court and executive branch have recognized the important role of the airport proprietor in developing noise abatement programs consonant with local conditions.

The maintenance of a fair and efficient system of air commerce, of course, mandates that each airport operator be circumscribed to the issuance of reasonable, nonarbitrary and nondiscriminatory rules defining the permissible level of noise which can be created by aircraft using the airport. Concorde I, supra at 84. We must carefully scrutinize all exercises of local power under this rubric to insure that impermissible parochial considerations do not unconstitutionally burden interstate commerce or inhibit the accomplishment of legitimate national goals. See Douglas v. Seacoast Products, 431 U.S. 265, 97 S.Ct. 1740, 52 L.Ed.2d 304 (1977). See also 49 U.S.C. § 1651(a) ("provision of fast, safe, efficient and convenient transportation"); 49 U.S.C. § 1346 ("encourage . . . the development of civil aeronautics and air commerce"). And, of course, our task of monitoring the proprietor's observance of the strict statutory obligation to make his facility available for public use on fair and reasonable terms, and without unjust discrimination, 49 U.S.C. § 1718(1), is especially critical in the case of an important international port of call such as New York. For, if each village and hamlet were suffered to summarily prohibit the entry of foreign-made or owned aircraft without promulgating uniform rules, it could make a sham of our country's binding treaty commitments to subject the air carriers of France and Britain only to evenly applied "laws and regulations." See U.S.-France Air Services Agreement, Art. V, 62 Stat. 3445, T.I.A.S. No. 1679 (1947); Bermuda Agreement, Art. 5, 60 Stat. 1499, T.I.A.S. No. 1507 (1946), renegotiated, see Dep't of State Bulletin, Vol. LXXVII, No. 1990 (Aug. 15, 1977); see also Convention on International Civil Aviation (Chicago Convention), 61 Stat. 1180, T.I.A.S. No. 1591 (1946).

We thus urged in Concorde I that it was manifestly imperative under our cooperative scheme of aircraft regulation for the Port Authority expeditiously to establish reasonable, nonarbitrary and nondiscriminatory noise regulations at JFK. This it has not done. Rather, the Port Authority has steadfastly refused to accord landing rights to an airplane that is capable of meeting the rule that has consistently been applied to all other aircraft for nearly twenty years — 112 PNdB.

The district judge, after a hearing, found that the studies by the Authority's consultants were merely redundant of work already thoroughly performed by other agencies. This finding by the judge is not erroneous. We are not, of course, to be understood as saying that the Port Authority must slavishly accept Secretary Coleman's conclusions; but neither can it stall indefinitely when all the information at its disposal either confirms the SST's ability to meet existing noise rules or is impotent to dissuade other responsible officials that the impact of Concorde's low frequency energy emissions on airport neighbors will not be more than minimal at most.

While there are no absolute standards by which it may be determined that an inquiry is not being conducted with reasonable dispatch, a court will closely scrutinize the nature and character of the problems before the agency to assess whether the path it has chosen to pursue will resolve those issues in the reasonably foreseeable future. Cf. Deering-Milliken, Inc. v. Johnston, 295 F.2d 856 (4th Cir. 1961). Thus, the Port Authority claims that its consultants have found the low frequency vibrations of the Concorde a unique source of annoyance, and begs our indulgence as it petitions for federal aid to develop a "vibration-rattle index." But the federal government shows little interest in the vibration problem, and the President has determined to permit Concorde service in thirteen American cities despite the alleged rattle. We presume the President's decision was prompted by reports, after sixteen months of operations at Dulles, proving SST-induced vibrations — which Secretary Coleman had predicted to be "slight, brief and barely perceptible" — even less noticeable than originally anticipated and essentially equivalent to those emitted by long range subsonic aircraft. Accordingly, it is highly unlikely that the federal government will soon expend large amounts of money on a project — the development of a vibration-rattle index — that the Department of Transportation dubs a "useless undertaking".

Moreover, it is also clear that the Port Authority is not willing to finance such a project. Dr. Kryter as long ago as March of this year reported significant progress in quantifying a vibration-rattle index. In his opinion the elusive mystery of additivity could be unlocked in less than one year, although at considerable cost. The Port Authority has shown no inclination to fund such an endeavor, yet seeks our sanction to ban Concorde flights while we await development of a noise standard that may never eventuate. We would be remiss if we were to allow the Port Authority to dawdle further on the basis of studies that by its own admission are inconclusive in a manner that threatens irreparable economic injury and constitutes treatment that in anything but even-handed. See Office of Communication of the United Church of Christ v. FCC, 138 U.S.App.D.C. 112, 425 F.2d 543 (1969) (Burger, J.).

The final reason assigned by the appellant for its delay in developing a vibration-rattle index and hence, a noise rule for SSTs is that the airlines' submission of revised operating procedures only six months ago forced Dr. Kryter essentially to commence his research anew. But the airlines' specific runway utilization and other proposals merely confirmed what had been apparent for months — that the Concorde could meet and surpass the longstanding 112 PNdB standard at JFK. In fact, the revised procedures, whose technical validity was soon assured by the F.A.A., proved that the plane was even quieter than theretofore supposed and comparable in noise intensity to the subsonic B707-320B. It is hollow to assert the "tardiness" of this unrequested submission as a justification for the Port Authority's inability to devise a suitable noise rule, particularly in light of Dr. Kryter's testimony that the airlines' April 1 data in no way altered his conclusion concerning the vibration issue.

III. RELIEF

Accordingly, we affirm the order of the district court so far as it dissolves the ban on SST flights at Kennedy Airport and permits the Concorde to serve New York under conditions detailed in federal operations specifications. Our holding, however, does not deny the Port Authority the power to adopt a new, uniform and reasonable noise standard in the future, assuming the longstanding 112 PNdB rule, which the Concorde concededly can meet, upon reasoned grounds is deemed inadequate. The district court's order is modified insofar as it fixes 112 PNdB as the only possible standard against which the Port Authority legally can measure the permissible noise of supersonic aircraft at JFK.

We underestimate neither the seriousness of the issues confronting the Port Authority nor the difficulties it has encountered in arriving at a suitable resolution. Its ultimate determination will have broad economic, political, social and environmental implications. But making sensitive decisions, and exercising sound judgment even in the face of some nagging uncertainty, is the daily fare of judges, administrators and other public officials. And we have asked no more of the Port Authority than that it meet its admittedly heavy responsibility by adopting a fair noise rule within a reasonable period of time.