MANSFIELD, Circuit Judge (concurring in part):

I agree that the district court's order, as modified, should be affirmed. However, I cannot agree with the majority's characterization of the Port Authority's failure to establish SST noise and vibration standards as "procrastination," "total resistance," "abdication of responsibility," or as "tantamount to refusing to address" the issue, much less that the Port Authority has been politically motivated or "anything but even-handed." In my view these characterizations are unwarranted and ignore the serious problems that have been encountered in obtaining the scientific and attitudinal data required for a decision of such long-range, far-reaching proportions for New York residents. The establishment of noise standards for SSTs at JFK Airport is a matter of vital importance, not just to the plaintiff Airlines and to the maintenance of cordial international relations with England and France, [FN1] but to more than 500,000 people living near JFK. The commercial SST may not be synonymous with progress if the price is to be increasing noise pollution and vibration of deafening proportions for thousands. Because of this impact on human lives the issue has warranted most careful study even if some delay ensued.

[FN1] Ironically it was Napoleon who said, "I have made noise enough in the world already." Reported in B. O'Meara, Napoleon in Exile, 1816 (AMS Press ed. 1969), as quoted in The Home Book of Quotations 625 (B. Stevenson ed. 1967).

I cannot agree with my distinguished colleagues that this record supports a finding that the Port Authority has acted in bad faith or has been derelict in its duty. I am willing to accept the Authority's contrary contention, which appears to be supported by evidence, that it has proceeded in good faith to make a conscientious effort to develop a noise and vibration standard that will be fair and reasonable to plaintiffs and to other prospective SST carriers seeking to use JFK as well as to the more than 500,000 people residing within the sound and vibration "footprint" of SST takeoffs from that airport but that it has been stumped by inability (1) to construct a "noise-vibration" measuring device or index that will be generally acceptable to acoustical scientists, and (2) to fix a maximum level on such an index that would properly balance the conflicting interests of the carriers and the airport's neighbors.

Nevertheless, I do not believe that any agency such as the Port Authority is entitled to exclude carriers indefinitely and unconditionally from the use of its facilities without making definitive findings, based on substantial evidence, that the proposed use would jeopardize the health, safety or welfare of the public. This the Port Authority cannot do at this stage. It finds itself in the difficult position of not having enough evidence at this stage to bar the Concorde completely and yet not having enough data to fix reasonable and non-discriminatory noise-vibration levels that will withstand scientific and legal scrutiny. The picture is complicated by the necessity of investing additional hundreds of thousands of dollars of public funds, over and above the more than $250,000 already spent by the Authority, on further research and attitudinal surveys needed to complete the job.

Under the circumstances, I concur in the view that continuation of the Port Authority's ban on the Concorde cannot be justified, not because of any fault on its part but because there comes a time when the hourglass runs out and even a public agency must "fish or cut bait." That time has now passed. Moreover, the limited test use of JFK contemplated by the plaintiffs under the Secretary of Transportation's decision might serve the useful purpose of providing the very basis that the Authority needs for on-site monitoring and attitudinal surveys essential to the formulation of reasonable noise-vibration regulations for SST craft.

In my view, the problem of measuring the unique combination of noise and vibration generated by the Concorde and of establishing maximum levels of public tolerance is not nearly as simple as my colleagues would make it appear. If this were simply a case of securing SST compliance with the Port Authority's existing noise standard for subsonic jets 112 PNdB there would be no justification for any Port Authority delay once the plaintiffs, in March 1977, finally developed new operating procedures for the Concorde at JFK that would minimize the plane's noise impact so that it could meet the existing subsonic test insofar as it creates noise of a conventional nature. But the problem is more difficult and far-reaching than that. The reasonableness of the Port Authority ban on Concorde flights must be considered in light of what the Port Authority knew about the noise and vibration impact of commercial supersonic air travel when it imposed the ban on March 11, 1976. As Secretary of Transportation William T. Coleman, Jr. observed in his February 4, 1976, decision allowing a 16-month test of the Concorde at Dulles, and, subject to Port Authority permission, at JFK, the Concorde possesses unique noise and vibration characteristics quite different from subsonic aircraft. Secretary Coleman's decision states:

"Low frequency components of aircraft noise create community annoyance through induced vibrations of homes and buildings near airports. Because noise generated by the Concorde has a much greater low-frequency content than that of comparable subsonic jets, there has been substantial public concern about the effect of induced vibrations on historic and other buildings, structures, windows and interior furnishings such as pictures, lamps, and dishes. Low frequency sound travels much more readily through the atmosphere and through structures than does the sound produced by other jets. Thus, if the Concorde and a subsonic jet were to generate noise of equal intensity at the aircraft, the Concorde's noise would be of a greater intensity at greater distances from the aircraft, since its sound energy would not dissipate as rapidly. This effect was studied thoroughly by the FAA and is described fully in the final EIS."

The final Environmental Impact Statement prepared by the Federal Aviation Administration and released in September 1975, upon which Secretary Coleman based his decision, had reported:

"From Figure 6B, the Concorde's perceived loudness or noisiness under the takeoff flight path is double that of a B-707, four times the noisiness of a B-747 and eight times as loud as a DC-10. The perceived loudness of the Concorde will be annoying. It will interfere with communications and may cause startle.

"The Concorde's low frequency spectral content is five times that of present subsonic jet aircraft (Figures 19-22). This low frequency aspect will induce some perceptible vibrational impact. However, while perceptible, the vibrational impact will not exceed any existing standards for structural damage (See Section VI.C.2 and Figures 41-46). Since the low frequency content of Concorde's noise signature will produce some household rattle and interfere with communications, it will be annoying to residents in the immediate airport vicinity."

"On the Concorde's takeoff using noise abatement procedures, for example, 47.6 square miles of land are subjected to noise levels at or above 100 EPNdB; comparable figures for the B-707 and the B-747 are 7.49 square miles and 2.91 square miles, respectively. This level of noise, 100 EPNdB, is approximately equal to, or perhaps slightly less noisy than, heavy city traffic at a distance of 25 feet, although the period of exposure to the aircraft noise would be short, generally under a minute."

[FN2] The Federal Aviation Administration's final Environmental Impact Statement analyzes the noise impact of the Concorde in terms of four "noise descriptors," which are scientific methods of representing different aspects of a particular noise impact. The Noise Exposure Forecast (NEF) is a "noise descriptor" that describes the cumulative noise impact of all the aircraft operating at a given airport during the course of a day. It includes corrections for irritating whines or discrete frequencies in aircraft noise, and for noises occurring during those periods of the day, such as late evening, when loud noises are more disturbing. Use of the NEF descriptor permits an assessment of the extent to which Concorde operations will increase the total noise impact on persons living near an airport.

Secretary Coleman stated that the following NEF values have been generally accepted as a valid means of assessing community reaction to aircraft noise exposure:

(1) Individuals residing in an area measured at between NEF 30 and NEF 40 "may complain";

(2) Individuals residing within an NEF contour greater than 40 can be expected to complain "vigorously and repeatedly";

(3) The threshold of "possible hearing loss" is reached at NEF 45. The Secretary's Decision on Concorde Supersonic Transport 44-48 (Feb. 4, 1976).

Moreover, the tests conducted at Dulles since Secretary Coleman's decision, while leading to a federal authorization of Concorde landings at various airports in the United States, subject to reasonable and non-discriminatory local regulations, have not indicated that the existing noise regulation at JFK would be adequate to provide reasonable protection against excessive noise pollution by SSTs in the future. Despite Secretary Coleman's prediction that the effect of the proposed Concorde operations at Dulles would be "hardly perceptible," the number of noise complaints at that airport has increased from a total of 77 during the three-year period prior to the introduction of the Concorde to a total of 1,762 complaints during the first 12 months of Concorde operations, of which 1,387 or 79% were complaints about the Concorde. See Statement of Henry S. Eschwege, Director, Community and Economic Development Division, United States General Accounting Office, before the Subcommittee on Environment, Energy and Natural Resources of the House Committee on Government Operations, September 7, 1977.

The lodging of some 1,387 complaints against Concorde noise during only one year of very limited test operations at Dulles, registered by those located in an area where only 1,000 people reside, would indicate that even though the Concorde may be able to meet existing Port Authority standards, it may also, because of its additional noise and vibration pollution, be so objectionable at JFK, where over 500,000 people reside within the same contours, as to necessitate more stringent, additional regulations. Even assuming, despite this disproportionately high number of protests from Dulles' neighbors that the Concorde would successfully "play in Peoria" or other less densely populated areas, this does not mean that it would go over, noisewise, in heavily-populated New York.

These circumstances, standing alone, might justify a substantial pause in the development of new noise-vibration standards at JFK. In addition, there are other justifications for much of the Port Authority's delay. First, of course, there has been the inherent difficulty in developing a method or index for measuring or quantifying the combination of "vibration plus noise" generated by the SST that will be generally acceptable to acoustical experts. Secondly and most difficult of all is the task of determining the level at which this "vibration plus noise" should be viewed as too excessive to be acceptable to the average "reasonable person" (assuming such a person is to be treated as the standard for this purpose). The Port Authority is not being called upon merely to fix a criterion for a few Concorde flights per day on a limited, experimental basis, but to establish a gauge that will be used for all future SSTs using JFK, of which there may be hundreds, if not thousands, of flights in the years to come. Last, but not least, the Port Authority faces the prospect that if the present trend toward increasing the liability of airport proprietors to their neighboring residents for excessive noise in takeoffs and landings should continue, see Griggs v. Allegheny County, 369 U.S. 84, 82 S.Ct. 531, 7 L.Ed.2d 585 (1962); Greater Westchester Homeowners Assn. v. City of Los Angeles, 13 Avi. 18, 116 Cal.Sup.Court 1975, the Authority faces possible exposure to many millions of dollars in damages in suits by residents in the vicinity of JFK, based on "taking" or "nuisance" theories, unless it adopts carefully-considered reasonable regulations tailored to the unique environmental problems created by the SST.

For these reasons I do not share the view that the Port Authority has in the past been at fault in banning Concorde flights at JFK while it sought to develop a new standard for regulating the noise and vibration produced by supersonic aircraft. However, the circumstances have now changed in a way that leads me to conclude that Concorde test flights into JFK for the period permitted under Secretary Coleman's decision should be permitted. The Port Authority's research effort has stopped at the point where its expert, Dr. Karl Kryter of the Stanford Research Institute, is able to assess only the comparative potential for vibration produced by supersonic and subsonic aircraft. Dr. Kryter virtually concedes that real-life attitudinal data is now essential to enable him to determine how much irritation caused to neighboring residents by Concorde noise and vibration will be reasonably tolerable. As both the majority here and Secretary Coleman have observed, reaction to noise and vibration is essentially a subjective phenomenon. The most sophisticated noise-vibration rattle index will not, by itself, enable the Port Authority to determine the point on the index beyond which an SST may not go because of the excessive irritation to airport neighbors. This judgment must be based, in part, on human experience, which cannot be measured intelligently without actual test flights.

The Port Authority contends that test flights should await further experimentation and study. This argument is untenable, however, in light of the Authority's own disinclination to fund further research, and the federal government's apparent satisfaction for its limited purposes with the information currently available. [FN3] The Port Authority's position has thus been reduced to the assertion that it can justify its ban indefinitely on the basis of its belief that the Concorde will exceed acceptable noise and vibration levels. Yet it is unwilling to define the standards that the airlines are expected to meet. This is an insufficient basis to justify the exclusion of an aircraft that concededly meets the Port Authority's only existing noise regulation. Although plaintiffs will now be permitted to go into JFK on the limited test basis authorized by Secretary Coleman, the Port Authority retains the power, if, as, and when it obtains the essential data, to prescribe reasonable noise and vibration standards that might have the effect of authorizing, limiting or barring the use of JFK by SSTs, depending on the Authority's findings.

[FN3] As Chief Judge Kaufman's opinion notes, Secretary of Transportation Brock Adams has recently taken the position, on the basis of a report by his Department's Office of Noise Abatement dated September 1, 1977, that it is unnecessary to define or quantify a "vibration-rattle" index before establishing new noise standards for aircraft, in view of findings that structural vibrations and associated rattling of interior furnishings by Concorde landings were not essentially different from those caused by long-range subsonic aircraft. However, the underlying report made it clear that it was limited to landings, as distinguished from takeoffs, and even then to "Concorde SST approaches utilizing a decelerating procedure" in lieu of a "conventional stabilized approach procedure." With respect to the latter the report concluded:

"Low-frequency aircraft noise may induce sympathic (sic) vibrations in structures located near aircraft flight paths. At a 'worst-case' location directly under the approach path one nautical mile from runway threshold, the low frequency noise levels generated by Concorde SSTs using a conventional stabilized approach procedure are higher than levels generated by long-range subsonic aircraft (differences in sound pressure level from 4 to 16 dB in one-third-octave bands centered at 125 Hertz and below)."

Moreover, the foregoing represents solely the reaction of the Department of Transportation, obtained at the request of the United States General Accounting Office, to Dr. Karl Kryter's report regarding the prospective impact of Concorde noise around JFK, which predicted a severe reaction by residents to the rattle. The General Accounting Office reported to Congress on September 7, 1977, through Mr. Henry Eschwege, that the Kryter report was also under review by NASA and EPA, which would advise whether they favored the development of a vibration-rattle index.

It should further be noted that Secretary Brock Adams' decision on September 23, 1977, to permit Concorde SSTs to land at some 13 American cities is subject to the condition that airport proprietors, including the Port Authority, retain their right "to limit or ban aircraft operations at their airports through reasonable, non-discriminatory noise rules." Except for Dulles Airport, therefore, the federal government's interest in the matter remains a limited one, amounting to little more than a proposal as far as use of various city airports is concerned.