E. Federal Preemption

In the Notice of Investigation, we advised that information provided by the NAA did not demonstrate that the NAA had a proprietary interest sufficient to bring the Stage 2 ban within the scope of the “proprietor exception” to Federal preemption. Specifically, the information did not show that the NAA had potential liability for existing levels of noise generated by aircraft using the airport.

In its Reply to the Notice of Investigation, the NAA contends that there is no Federal requirement that it demonstrate liability in order to impose a Stage 2 ban. Specifically, the NAA states that “there is simply nothing in [ANCA] or its legislative history that even implies that an airport proprietor must establish, or even discuss, potential liability as a predicate to imposing a Stage 2 restriction.” [141] The NAA also claims that since its Stage 2 ban was “adopted pursuant to an express Congressional grant of power [i.e., 49 U.S.C. 47524(b)],” it cannot be preempted. [142] In the NAA’s view, ANCA “gives a proprietor the express right to ban or otherwise restrict Stage 2 aircraft.” [143] Local governments may adopt noise abatement measures that do not impinge on aircraft operations. [144] However, under Federal preemption law, states and localities cannot regulate noise by controlling the flight of aircraft taking off or landing at local airports, for this method of regulating noise control is to be exercised exclusively by the Federal government. [145] A limited exception to this preemption (i.e., the “proprietor powers exception”) exists for an airport proprietor that faces actual or potential liability for noise damages from aircraft using its airport. [146] Congress preserved this existing law when it enacted ANCA. [147]

This case presents an issue of first impression for the FAA: whether an airport proprietor must face actual or potential liability for noise damages in order to restrict aircraft operations. As discussed in the Background section of this Determination, FAA regulations provide that residential land use is normally compatible with noise levels below DNL 65 dB. [148] However, the NAA’s ban addresses noise levels below DNL 65 dB. As discussed below, while it is reasonable to presume liability exposure within the DNL 65 dB contour, which is used by Federal agencies and recognized by the courts as the threshold of noise compatibility for residential land use, there is not the same basis for such a presumption outside the DNL 65 dB contour. Therefore, in reviewing the Stage 2 ban, the FAA requested that the NAA provide information regarding its actual or potential liability for noise damages. The NAA conceded that there is no judicial determination of actual liability but asserted that it had potential liability based on alleged oral and written threats of liability and complaints. As explained below, these alleged threats and letters do not demonstrate that the NAA faced actual or potential liability for noise damages based on aircraft noise levels existing when the Stage 2 ban was implemented. In the absence of such actual or potential liability, the Stage 2 ban is preempted. Moreover, none of the arguments advanced by the NAA in its Reply to the Notice of Investigation provide a basis for finding otherwise.

1. Federal Preemption Law Generally

In 1973, the Supreme Court held that a local noise ordinance was preempted under the FAA’s implementing statute, the Federal Avia tion Act of 1958 (as amended in 1968), and the Noise Control Act of 1972. In City of Burbank v. Lockheed Air Terminal, [149] the Supreme Court further held that the Federal Government regulates aircraft and airspace pervasively, [150] preempting regulation of aircraft noise by state or local governments. [150] While acknowledging that noise control is “deep-seated in the police power of the States,” the Supreme Court held that the pervasive control over aircraft noise vested in the Federal Government left no room for local curfews or other local controls.” [152] The Court noted the fact that since the FAA is required to balance many interdependent factors, a “uniform and exclusive system” of federal regulation was required if the Congressional objectives underlying the Federal Aviation Act were to be fulfilled. [153]

While the Supreme Court acknowledged that the Federal Government has full control over aircraft noise, preempting state and local control under their police power, the Court left open the question of whether an airport proprietor could enact aircraft noise restrictions based upon its proprietary powers as the landlord of the airport. [154] Federal courts since Burbank have recognized the “proprietary powers exception,” under which airport proprietors may enact noise-based restrictions affecting aircraft operations in order to protect themselves from liability for noise damages. [155] The rationale for the proprietary powers exception to Federal preemption is the fact that airport proprietors (rather than the airlines or the Federal Government) bear monetary liability for excessive aircraft noise under the Supreme Court’s decision in Griggs v. County of Allegheny. [156] As stated by the Ninth Circuit Court of Appeals in San Diego Unified Port District v. Gianturco, which interpreted Griggs:

The rationale for this exception is clear. Since airport proprietors bear monetary liability for excessive aircraft noise under [Griggs], fairness dictates that they must also have power to insulate themselves from that liability. But before an entity may possess this power, it must bear the responsibility, either actual or potential, for excessive aircraft noise. [157]

In the Eleventh Circuit as well, a showing of whether a proprietor has “potential liability for excessive noise” is also required to invoke the proprietary powers exception. Pirolo v. City of Clearwater, 711 F.2d 1006, 1009 (11 th Cir. 1983), reh’g denied, 720 F.2d 688 (11th Cir. Fla. 1983) (if the city had not contracted away its right to impose the desired restrictions, the court would have inquired whether the city faced potential liability for excessive aircraft noise).

Thus, noise liability serves as the basis for the extraordinary ability of local airport proprietors to enact noise-based restrictions that impinge on aircraft operations in an otherwise preempted area. To invoke lawfully the proprietary powers exception, the NAA must face either actual or potential liability for noise damages caused by aircraft using its airport. In this case, if no actual or potential liability exists, then the Stage 2 ban is preempted.

Although numerous Federal courts have addressed the proprietor powers exception to Federal preemption, no court has directly addressed the issue of whether noise conditions at a particular airport present a legitimate liability concern sufficient to invoke the proprietary powers exception. As a result, the existing case law noted by the NAA [159] addressing the proprietary powers exception is of limited applicability to the NAA situation.

The legislative history surrounding the 1968 amendments to the Federal Aviation Act of 1958 and the Noise Control Act of 1972 supports the FAA’s position that an airport proprietor must face actual or potential liability for noise damages in order to invoke the proprietary powers exception. The origins of the proprietary powers exception are described in a June 22, 1968, letter by Secretary of Transportation Alan S. Boyd to Senator Monroney, Chairman of the Senate Subcommittee on Aviation, in response to a question concerning the 1968 amendments.

During the hearings, subcommittee members expressed their concern regarding whether, by entering into the aircraft noise abatement field, the Federal Government was taking on noise liability for aircraft operations. In response to a question from Chairman Monroney – “Will enactment of this legislation causing direct Federal involvement in the field of aircraft noise abatement and control increase the legal liability of the Federal Government for damage and damage claims caused by aircraft noise or sonic boom?” – Secretary Boyd’s legal advisor, Matthew S. Perlman, answered, “We see nothing in this legislation which would affect the liability of the Federal Government as spelled out by the Supreme Court in Griggs v. Allegheny County.” [160] In response to a further question from the Chairman on the extent to which the Federal Government would be liable for aircraft noise by enacting noise standards, Perlman further testified, “We do not believe we would. Under the Supreme Court [Griggs] decision, the airport is required to take easements, noise easements, and clearance easements, necessary for the operation of the airport.” [161] Chairman Monroney’s next question – “Would this legislation to any degree preempt State and local government regulation of aircraft noise and sonic boom?” – led to Secretary Boyd’s requesting permission to “submit an opinion for the record” on preemption. [162] The June 22, 1968, Boyd letter resulted.

The Boyd letter noted that “the Federal Government presently preempts the field of noise regulation insofar as it involves controlling the flight of aircraft” and that under the proposed amendments to the Federal Aviation Act, “[s]tate and local governments will remain unable to use their police powers to control aircraft noise by regulating the flight of aircraft.” [163] Against this backdrop of Federal preemption, the Boyd letter described the rights of an airport proprietor as follows: However, the proposed legislation will not affect the rights of a State or local public agency, as the proprietor of an airport, from issuing regulations or establishing requirements as to the permissible level of noise which can be created by aircraft using the airport. Airport owners acting as proprietors can presently deny the use of their airports to aircraft on the basis of noise cons iderations so long as such exclusion is nondiscriminatory. [164]

In explaining this exception to Federal preemption for airport proprietors, the letter stated that “[j]ust as an airport owner is responsible for deciding how long the runways will be, so is the owner responsible for obtaining noise easements necessary to permit the landing and takeoff of the aircraft.” [165] This statement reflects the Supreme Court’s Griggs decision, in which the Court ruled that it was the airport proprietor, Allegheny County, that “took the air easement in the constitutional sense. [The County] decided … where the airport would be built, what runways it would need, their direction and length, and what land and navigation easements would be needed.” [166]

The Boyd letter further explained that “[t]he Federal Government is in no position to require an airport to accept service by larger aircraft and, for that purpose, to obtain longer runways. Likewise, the Federal Government is in no position to require an airport to accept service by noisier aircraft, and for that purpose to obtain additional noise easements.” [167] This is true only because the proprietor rather than the Federal Government is subject to noise liability for operating the airport as discussed in Griggs. The Secretary succinctly summarized the heart of the letter as follows: “[t]he issue is the service desired by the airport owner and the steps [i.e., to reduce noise liability] it is willing to take to obtain the service. [168]

Thus, not only does the Secretary’s letter articulate the proprietary powers exception recognized by the Supreme Court in Burbank, but it also sets forth the exception’s rationale: that airport proprietors bear monetary liability for excessive aircraft noise under the Supreme Court’s 1962 Griggs decis ion. [169] Thus, based upon the original justification for the proprietary powers exception, a direct and necessary nexus exists between the ability of an airport proprietor to lawfully invoke the proprietary powers exception to regulate airport access for no ise purposes and being subject to noise liability.

The Senate Report on the 1968 amendments to the Federal Aviation Act quoted extensively from the Boyd letter, including the excerpts quoted above, and documented the Senate Commerce Committee’s explicit concurrence in Secretary Boyd’s views as expressed in the letter. [170] The subsequent reference to the proprietary powers exception in Section 105 of the Airline Deregulation Act of 1978, 49 U.S.C. 41713(b), [171] further indicates the weight Congress placed on the Boyd letter. The Supreme Court cited the Senate Report several times in Burbank, including the Boyd letter, as relevant legislative history. [172]

Consistent with congressional intent, as reflected in the Boyd letter, the FAA’s position is that an airport proprietor can regulate airport access for noise purposes only if existing noise conditions at the airport expose the proprietor to potential or actual Griggs liability. In the absence of such liability exposure, any such regulation would constitute a prohibited police power regulation and would thus be preempted under Burbank.

2. Actual Or Potential Griggs Liability Based On Current Conditions At The Airport

The FAA’s analysis thus begins with an examination of the NAA’s potential or actual Griggs liability exposure based upon noise levels at the airport. While it is reasonable to presume such liability exposure within the DNL 65 dB contour, which is used by Federal agencies [173] and recognized by the courts [174] as the threshold of noise compatibility for residential land use, there is not the same basis for such a presumption outside the DNL 65 dB contour.

As a result of the NAA proposing a direct ban on Stage 2 aircraft to address noise levels below DNL 65 dB, the FAA requested specific information from the NAA concerning its liability concerns. The NAA submitted documentation to support its claim that it faces liability for noise damages. In the submitted material, the NAA asserted that it faced a “credible and identifiable threat of liability from property owners.” [175] The FAA has examined each item used as justification by the NAA and concludes that the evidence in that material, and the record generally, does not demonstrate that the NAA had potential or actual noise liability exposure under Griggs for existing levels of noise generated by aircraft using the airport. As a result, the proprietary powers exception does not apply to the Naples situation and the Stage 2 ban is preempted as an invalid police power regulation under Burbank.

First, the NAA concedes that “[t]here is no judicial determination of noise-related liability against the NAA.” [176] Nor are there any pending lawsuits against the NAA. This is not surprising in light of what the NAA describes as its “success in promoting land use compatibility, considering and adopting both remedial and preventative noise abatement and mitigation measures, and attempting to address specific concerns about noise ….” [177]

Second, lacking any existing liability, the NAA argues that its Stage 2 ban may be justified not on any past, present, or pending lawsuits determining liability but on “identifiable and credible threats of suit” that “cannot be discounted” due to “settlements and judgments regarding other airports around the country.” [178] The NAA asserts that it has received oral and written threats of litigation claiming damages for inverse condemnation from the owner of Rock Creek Campground, which lies within the DNL 60 dB contour. According to the NAA, the campground owner recently has attempted to negotiate regarding his noise-related concerns while preserving the right to sue. However, this assertion by the NAA does not reveal any information about the noise exposure faced by the campground owner. The NAA also states that it has received “numerous informal complaints” from other property owners located in areas below the DNL 65 dB noise contour. However, the NAA has not provided any record evidence of such “informal complaints.” The only record evidence identifying the location of complaints, as depicted in section VI.F.1.c.i. (see Figure 1) indicates that the vast majority of the complainants are located well outside the DNL 60 dB contour. This data does not support NAA’s claim that it has received “numerous” complaints, informal or otherwise, from residents within the DNL 60 dB contour. Finally, the fact that the NAA “believes it is possible” that it may be sued by the campground owner or by other property owners, and the fact that there exist general discussions of inverse condemnation and nuisance in legal encyclopedias (as noted by the NAA) is not sufficient to permit the NAA to restrict aircraft operations.

As discussed in more detail later in this determination, the record shows that when the NAA implemented the Stage 2 ban, the City and County allowed residential development within the DNL 60 dB contour. In addition, the record indicates that the NAA was able to purchase an easement for a mere $10 for an entire condominium complex in response to an alleged threat by the developer of the Waterfront condominium complex (located within the DNL 60 dB contour) to take legal action after new residents began complaining about airport noise. [179] These facts are not consistent with the NAA’s assertion that it faces potential noise liability exposure.

Third, the NAA states that it is not aware of even a single inverse condemnation case in which the cumulative noise level experienced by a plaintiff, as measured by the DNL metric, was the basis for, or a factor in, the court’s decision. [180] From this, the NAA argues that “it cannot ignore potential claims from homeowners simply because a property may be located outside the 65 dB DNL contour.” [181] However, in the same paragraph, the NAA then acknowledges that it is possible that “property owners whose property lies within the 60 dB DNL contour could not maintain a claim for inverse condemnation ….” [182]

Examples of cases in which DNL noise levels have been a factor in courts’ decisions include Stephens v. United States, [183] (noted in the NAA’s Supplemental Analysis, page 13, footnote 39); Persyn v. United States; [184] and Baker v. Burbank-Glendale-Pasadena Airport Authority. [185] In Persyn, the U.S. Court of Federal Claims referred to the HUD residential standard of DNL 65 dB in determining the onset of “high noise levels” that could support a taking claim. [186] In Baker, an action by airport neighbors for inverse condemnation and nuisance, the trial court had determined that “CNEL [Community Noise Equivalent Level] [187] contours provided a consistent and accurate means for distinguishing between the various plaintiffs’ claims, and that the cutoff line should be drawn at the 65 decibel CNEL level.” [188] The California Court of Appeals found that “[t]he evidence substantially supports the court’s determination that CNEL values exceeding 65 decibels are sufficiently intrusive to amount to a taking or to give a rise to a prescriptive easement, and that lesser CNEL values are not.” [189]

Fourth, to demonstrate further that “there exists a credible risk of liability,” the NAA offers a description of legal standards governing inverse condemnation and nuisance claims under Florida law. The NAA asserts that it faces liability under the constitution and laws of the State of Florida, especially since “Florida courts do not focus on the physical location of the property and/or actual noise levels but instead on the nature of the overflights and the consequential damage, including effects on the market value of particular parcels.” [190] The NAA states that it recognizes itself “to be exposed to liability under the constitution and laws of the State of Florida.” [191] However, it is not clear from the documentation provided by the NAA how the NAA can support such a categorical statement. As the NAA correctly states, a required element for inverse condemnation in Florida is a substantial adverse impact on the market value of the property. However, reduced appreciation in value is not sufficient. [192] The NAA’s submission shows that property prices have increased significantly, not decreased. According to the NAA, properties in the area have been appreciating at a rate of approximately 15 percent per year. [193] In fact, the NAA has utilized property values in the affected areas within the DNL 60 dB contour to demonstrate the benefits of banning Stage 2 aircraft. [194]

The NAA states that in addition to claims for unlawful takings, Florida courts have also considered suits for damages resulting from airport and aircraft activity based upon nuisance claims (e.g., noise, vibrations, and air pollution). The NAA states that analysis of nuisance claims in Florida, like inverse condemnation claims, “turns on the damage resulting from the offensive activity rather than the particular location of or noise experienced by the plaintiffs.” [195] However, the “law in Florida about airport operations has long been that the lawful operation of such a facility in the ‘usual, normal and customary manner prescribed’ cannot constitute a nuisance.” [196] In addition, in Corbett v. Eastern Air Lines, Inc., [197] where operators of a restaurant adjacent to an airport sued the air carrier alleging the noise and other effects of its aircraft constituted a private nuisance, the court noted that the location of the complaining party was an important factor. [198]

Finally, in an attempt to further demonstrate liability, the NAA provides “several specific reported instances” where airport owners have had to defend litigation initiated by property owners in which the property at issue was located in areas exposed to noise less than DNL 65 dB (Wake County, North Carolina; DuPage County, Illinois; Palm Beach County, Florida, and Plainfield, Indiana). [199] However, only one case involves a Florida airport and none of the four cases resulted in a judicial determination of liability outside the DNL 65 dB contour. Moreover, the “reported instances” come from newspaper articles and anecdotal telephone conversations between the NAA counsel and unknown parties.

3. The NAA’s Other Arguments Regarding Federal Preemption

In NAA’s Reply to the Notice of Investigation, it argues generally that its Stage 2 ban is not preempted because it “was not adopted pursuant to the proprietor exception contained at 49 U.S.C. § 41713(b)(3) but rather pursuant to 49 U.S.C. § 47524(b).” [200] NAA further asserts that because 49 U.S.C. § 47524(b) “gives a proprietor the express right to ban or otherwise restrict Stage 2 aircraft,” the ban “cannot be preempted because it was adopted pursuant to an express Congressional grant of power.” [201]

The NAA’s argument has no merit. The Stage 2 ban was not enacted pursuant to an “express Congressional grant of power” under ANCA. As discussed in detail in section VI.A. above, ANCA did not supersede any preexisting law with respect to noise or access restrictions on operations by Stage 2 aircraft. Thus, ANCA did not affect preexisting law regarding Federal preemption of aircraft noise regulation, including the proprietor exception as recognized by Congress and the courts. As explained above, ANCA imposed additional requirements that must be met by airport operators before they can implement Stage 2 restrictions. Compliance with these requirements, however, does not establish an airport proprietor’s underlying authority to adopt such a restriction. Lawful noise or access restrictions are enacted by airport operators pursuant to their proprietary powers, the exercise of which is allowed by the proprietary powers exception to Federal preemption. [202] 202 ANCA does not provide any independent authority or power for an airport proprietor to enact a restriction.

Even if ANCA did expressly authorize airport operators to implement restrictions on Stage 2 aircraft operations, this would not immunize the NAA’s Stage 2 ban from Federal preemption, as the NAA asserts. In New England Legal Foundation v. Massport, [203] Massport enacted its capacity enhancement plan (PACE) leading to changes in rates and charges assessed to air carriers pursuant to the Anti-Head Tax Act (AHTA). [204] However, PACE did not survive the preemption challenge. The First Circuit reversed the district cour t for failing to defer to DOT/FAA’s primary jurisdiction to interpret 49 U.S.C. 41713 “and the issues raised in these cases thereunder.” [205] Massport relied upon the fact that the AHTA permits reasonable landing fees, but the court found the pricing scheme to be preempted under 49 U.S.C. § 41713.

The NAA next argues that even if its power to adopt the Stage 2 ban “emanates from a reserved power recognized in Section 41713 rather than an express grant contained in Section 47524,” the ban is valid because § 41713 does not preempt an airport proprietor from carrying out its proprietary rights and powers. This argument is circular and lacks any merit. Obviously, the mere fact that an airport proprietor enacts an airport noise restriction does not establish that the restriction comes within the proprietary powers exception.

In its Reply, the NAA also asserts that its view of its authority to adopt the Stage 2 ban is supported by: (1) a statement in the 1969 preamble to 14 C.F.R. Part 36; and (2) a table in an FAA advisory circular relating to Part 150. The Part 36 preamble states that the “[r]esponsibility for determining the permissible noise levels for aircraft using an airport remains with the airport proprietor.” This statement, which is consistent with a similar statement in the Boyd letter, discussed above, does not address the scope of the proprietor exception. The FAA recognizes that Congress did not intend to completely preempt airport proprietors from regulating aircraft noise. However, any such regulation remains subject to the supremacy of Federal law. If not within the limited scope of the proprietor exception as recognized by Congress, the regulation is preempted.

The advisory circular referenced by the NAA appears to be AC 150/5020-1, which includes a “matrix of noise control actions . . . , [which] while not necessarily exhaustive, illustrates an array of options or possible solutions to a cross section of noise compatibility problems.” [206] A footnote to the matrix, which applies to various actions listed in the matrix that are marked with an asterisk, states: “These are examples of restrictions that involve FAA’s responsibility for safe implementation. They should not be accomplished unilaterally [sic] by the airport operator.” [207] This footnote is not applied to either “Limitations on Number or Types of Operations or Types of Aircraft” or “Use Restrictions,” both of which are listed on the matrix. [208] On this basis, the NAA appears to argue in its Reply that “Use Restrictions” and “Limitations on Number or Types of Operations or Types of Aircraft” cannot be Federally preempted. The NAA reads far too much into the matrix and the accompanying footnote, neither of which addresses the scope of the proprietor exception to Federal preemption. The footnote, and the actions listed on the matrix to which the footnote applies (e.g., restrictions on aircraft ground movements, raising glide slope angle or intercept, power and flap management), explicitly relate to the FAA’s safety responsibilities. Moreover, the same paragraph of the advisory circular that references the matrix also states that “[e]ach alternative considered should…be legally implementable within existing State/Federal legislation and/or regulation.” [209]

NAA finally argues that Federal preemption is a matter of Constitutional law, “not a matter of Agency interpretation of regulations, or for that matter, grant assurance contracts. Violation of a grant agreement provision is just that (violation of a contract term), and cannot be reformulated into a Supremacy Clause violation.”

NAA’s argument has no merit. Federal agencies routinely must interpret and apply the statutes they are charged with administering. They do so in a legislative context when promulgating rules. They do so in an adjudicatory context when processing complaints under administrative processes such as 14 C.F.R. Part 16. In short, the FAA and DOT, like other Federal agencies, must on occasion determine whether the Federal law entrusted to them is being complied with or not. In this instance, that requires a conclusion concerning Federal preemption.

Preemption is relevant to grant compliance because if the NAA’s Stage 2 ban is preempted, it is per se unreasonable under the grant assurances. Federal courts recognize the FAA’s power to interpret the law it is charged with administering, including the law of Federal preemption. As in the below cases, the NAA will have the right to appeal FAA’s determinations.

For example, in the Massport case, initiated by the filing of a complaint under 14 C.F.R. Part 13, the predecessor regulation to Part 16, a DOT administrative law judge (ALJ) made specific findings on Massport’s compliance with the Federal preemption provision. [210] The ALJ concluded that

the PACE plan was unconstitutional because it was preempted by federal law through the Supremacy Clause and because it was contrary to the Commerce Clause … The ALJ then ruled that the new Massport rate scheme violated section 105 of the Federal Aviation Act [49 U.S.C. 41713]. The conclusion flowed from his finding that the landing fees were unreasonable or discriminatory and were therefore impermissible within Section 105(b) “proprietary powers and rights” exception to Section 105(a) …. New England Legal Foundation v. Massport, 883 F.2d 157, 164-165 (1 st Cir. 1989).

In another FAA administrative complaint action, this time under Part 16, Centennial Express Airlines filed a complaint against Arapahoe County, Colorado, alleging that the County’s ban on all scheduled air carrier service violated the County’s AIP grant assurances and 49 U.S.C. 41713. The FAA made findings on compliance with the assurances and the Federal preemption provision. The FAA Director of Airport Safety and Standards issued a Director’s Determination concluding that the Arapahoe County Public Airport Authority’s ban on scheduled passenger service violated the grant assurances and section 41713. Those findings were reviewed by a Part 16 hearing officer in FAA Docket No. 16-98-05, 13-94-25, and 13-95-03, and by the Tenth Circuit Court of Appeals in Arapahoe County Public Airport Authority v. FAA, 242 F.3d 1213 (10 th Cir. 2001). The hearing officer affirmed the Director’s findings and the FAA’s ability to rule on “supremacy principles” (“Turning to supremacy principles, we reiterate that the issue before the FAA was whether the Authority complied with the conditions imposed on it by federal law and agreement with a federal administrative agency, in return for the Authority's receipt of federal funds.” 242 F.3d at 1220).

The Tenth Circuit noted that:

[t]his federal scheme regulating airport grant compliance is "designed in part to insure the maintenance of conditions essential to an efficient national air transport system, including access to airports on a reasonable and nondiscriminatory basis." City and County of San Francisco v. FAA, 942 F.2d 1391, 1395 (9th Cir. 1991), cert. denied, 112 S.Ct. 1665 (1992). On this point, we must agree with the Fifth Circuit that in the arena of aviation regulation "federal concerns are preeminent," and the Department of Transportation, through the FAA, is statutorily mandated to represent those concerns. American Airlines v. City of Dallas, 202 F.3d 788, 800-801 (5 th Cir. 2000). Indeed, it is "difficult to visualize a more comprehensive scheme of combined regulation, subsidization, and operational participation than that which Congress has provided in the field of aviation." New England Legal Foundation v. Massachusetts Port Authority, 883 F.2d 157, 172-173 (1st Cir. 1989) (discussing the FAA's primary role in administering and ensuring compliance with grant assurances) (quotation marks and citation omitted). This certainly tilts the balance toward the application of supremacy principles to protect against state courts trumping the federal interests and concerns embodied within the airport grant program.

Arapahoe, 242 F.3d at 1220-1221.

4. Conclusion On Federal Preemption

Because the evidence in the record does not show that noise conditions at the Naples Municipal Airport exposed the NAA to potential or actual liability for damages caused by noise from aircraft operations at the airport, there is no basis for the NAA to invoke the proprietary powers exception to Federal preemption. The NAA’s Stage 2 ban thus constitutes an unlawful exercise of police powers to regulate aircraft noise. As a result, the ban is Federally preempted and void. Even assuming that the Stage 2 ban fell within the scope of the proprietary powers exception, the ban would still be subject to the reasonableness and nondiscrimination requirements within the NAA’s Airport Improvement Program (AIP) contractual grant assurances.

F. Compliance With Grant Assurance 22 -- Reasonableness

The NAA maintains that the Stage 2 ban is not subject to the reasonableness requirement under the grant assurances. [211] However, as discussed more fully above, ANCA preserved the requirements under 49 U.S.C. § 47107(a) and related Grant Assurance 22 for the sponsor of a Federally-obligated airport to make its airport available for public use on reasonable terms to all types, kinds, and classes of aeronautical activities.

The NAA also maintains that the Stage 2 ban is “amply supported by a comprehensive study” that was “approved by the FAA.” 212 However, in addressing the NAA’s compliance with Part 161, the FAA determined only that the NAA’s Part 161 analysis “respond[ed] to the Part 161 consultation, notice and analysis requirements of Subpart C of that part.” [213] This determination was limited to the context of the “largely procedural” requirements of ANCA and Part 161, [214] and did not address whether the NAA’s analysis was sufficient to demonstrate the reasonableness of the Stage 2 ban under Grant Assurance 22.

In the alternative, the NAA argues that the Stage 2 ban is reasonable by any measure. [215] The NAA contends that the reasonableness of the ban is shown by the Part 161 Study, the Part 161 Study Response to Comments, the Supplemental Part 161 Analysis, and the pleadings and oral argument in NBAA v. NAA. [216] In addition to referencing these documents, the NAA, in its Reply, makes the following specific points regarding the reasonableness of the Stage 2 ban: (1) the Stage 2 ban addresses a real and significant noise problem; (2) the Stage 2 ban is amply supported by a comprehensive study conducted by qualified professionals and is targeted with precision to address a real and significant noise problem; (3) the Stage 2 ban does not place an undue burden on affected users; (4) the Stage 2 ban is supported by the NAA’s cost-benefit analysis; (5) the NAA need not fund additional noise insulation or otherwise institute alternative noise mitigation or reduction actions in order to justify a Stage 2 restriction as reasonable; (6) the NAA is authorized to consider the benefits of the Stage 2 ban for residents located within the DNL 60 dB contour; and (7) the NAA is not required to establish liability as a justification for adopting the Stage 2 ban. [217] In its order entitled “Airport Compliance Requirements,” which includes guidance regarding grant compliance requirements, the FAA states that noise-based airport use restrictions imposed by owners of Federally-assisted public use airports must, among other things, be reasonably consistent with reducing non-compatibility of land uses around the airport, not create an undue burden on interstate or foreign commerce, and meet both local needs and the needs of the national air transportation system to the extent practicable. [218] These standards derive from criteria for approval of airport noise and access restrictions under ASNA and Part 150. [219] In ASNA, Congress directed the Secretary of Transportation to “establish a single system for determining the exposure of individuals to noise resulting from airport operations” and “identify land normally compatible with various exposures of individuals to noise.” [220] In response to this congressional direction, the FAA determined, in 1981, that DNL was the proper noise metric for assessing land use compatibility with aircraft noise, and that residential land use is normally compatible with aircraft noise levels below DNL 65 dB. [221]

The FAA has continuously, consistently, and actively encouraged a balanced approach to address noise problems and discouraged unreasonable and unwarranted airport use restrictions. [222] It is long-standing FAA policy that airport use restrictions should be considered only as a last resort when other mitigation measures are inadequate to satisfactorily address the noise problem and a restriction is the only remaining option that could provide noise relief. [223] This policy furthers the Federal interest in maintaining the efficiency and capacity of the national air transportation system [224] and, in particular, the FAA’s responsibility to ensure that Federally- funded airports maintain reasonable public access in compliance with Grant Assurance 22. [225]

Consistent with these federal requirements and policies, the FAA interprets the requirement in 49 U.S.C. § 47107(a)(1) that a federally- funded airport will be “available for public use on reasonable conditions” as requiring that a regulation restricting airport use for noise purposes: (1) be justified by an existing noncompatible land use problem; (2) be effective in addressing the identified problem; and (3) reflect a balanced approach to addressing the identified problem that fairly considers both local and Federal interests.

Upon consideration of the evidence and argument presented by NAA, as explained in detail below, we conclude that the Stage 2 ban is not reasonable and therefore violates Grant Assurance 22. Specifically, based on the record evidence we conclude that the Stage 2 ban is not adequately justified by existing non-compatible land uses. In addition, it shows that even if its land use compatibility goal were justified, the NAA has not taken a balanced approach to achieve that goal that fairly considers both the local and Federal interests.

1. Noncompatible Land Use As A Justification For The Stage 2 Ban

As directed by Congress in ASNA, the FAA has established DNL as the metric for “determining the exposure of individuals to noise resulting from airport operations.” [226] Also in compliance with ASNA, the FAA has established the land uses normally compatible with exposures of individuals to various levels of noise. [227] The FAA determined that residential land use is “normally compatible” with noise levels of less than DNL 65 dB. [228] Under FAA guidelines, there are no existing noncompatible land uses around the Naples Municipal Airport because there are no noise sensitive land uses within the DNL 65 dB noise contour and because residential land uses below DNL 65 dB are compatible. The Stage 2 ban is, therefore, not justified based on noncompatible land uses according to Federal guidelines. However, airport proprietors may under Part 150 designate incompatible land uses at noise levels below DNL 65 dB based on local standards. [229]

Under Part 161, the “airport noise study area” for a proposed airport noise or access restriction “must include the noise contours required to be developed for noise exposure maps specified in [Part 150].” [230] The preamble to the Part 161 final rule explains that the intent was to “permit the applicant airport operator the same flexibility as that provided under Part 150.” [231] The preamble also explains that Part 150 “permits, for reasonable circumstances, a degree of flexibility in determining a study area and the compatibility of land uses to noise.” [232]

The proposal to adopt a restriction on airport access based upon a local land use compatibility standard presents the FAA with an issue of first impression with respect to compliance with Grant Assurance 22. Under Part 150, the FAA has approved non-restrictive (i.e., not restricting aircraft operations) remedial noise mitigation projects outside the DNL 65 dB contour based on “explicitly documented locally determined land use compatibility values.” [233] The agency considers such projects to be eligible for federal funding when supported by appropriate documentation from the sponsor and approved in a Part 150 program or FAA environmental document. [234] However, no airport proprietor has recommended a restriction on aircraft operations for approval under Part 150 based on a claimed local land use compatibility standard.

In its Reply to the Notice of Investigation, the NAA argues that the Stage 2 Ban is designed to address an “empirically observed noise problem” that is “a product of, and exacerbated by, the nature of the Naples community as a resort/retirement area and the seasonal fluctuation in population and aircraft operations.” [235] The NAA asserts that this noise problem is “reflected in incompatible land use surrounding the Airport and in complaint data.” [236] The NAA’s 2000 update of its Part 150 noise exposure map defines the “Naples Municipal Airport Land Use Compatibility Criteria” as follows:

In compliance with the FAA direction in Part 150 that airport proprietors must defer to local authorities in determining land use compatibility, the NAA is respecting the City of Naples and Collier County 60 dB DNL land use compatibility criterion, and considers residential land within the 60 dB DNL contour to be incompatible with airport noise. [237]

As discussed below, however, the record shows that when the Stage 2 ban was implemented, neither the City nor the County had determined that residential use was incompatible with aircraft noise levels lower than DNL 65 dB. [239] Given the NAA’s stated land use compatibility goal and its basis, the absence of such a determination of incompatibility rendered unreasonable the NAA’s use of the DNL 60 dB contour to justify the Stage 2 ban. [240]

In the NAA’s Part 161 Supplemental Analysis and its Reply to the Notice of Investigation, the NAA provides several local circumstances, besides the City and County ordinances, that it claims support the use of its land use compatibility goal of minimizing residential land within the DNL 60 dB contour for purposes of justifying the Stage 2 ban. A review of the applicable portions of these documents identified the following circumstances which the NAA believes provide a reasonable basis for its use of the land use compatibility goal: (a) the NAA faces a credible and identifiable threat of liability from property owners due to noise from aircraft using the airport; (b) the Stage 2 ban will address 40 percent of the noise complaints the NAA receives; and (c) residents in Naples have an outdoor lifestyle in a low-ambient-noise- level environment. [241]

Upon close review of the information submitted by the NAA to support its imposition of the Stage 2 ban, we find that: (a) at the time that the NAA implemented the Stage 2 ban, neither the City nor the County had prohibited residential development within the DNL 60 dB contour ; (b) the NAA’s contention that it is faced with credible and identifiable threats of liability from property owners is not supported by the record evidence; (c) the NAA’s use of complaint and Sound Exposure Level (“SEL”) data does not support a finding that the Stage 2 ban is reasonable; and (d) the NAA’s analysis of background and ambient noise levels is flawed and does not justify the NAA’s stated land use compatibility goal or the Stage 2 ban.

a. Allowance Of Residential Development Within The DNL 60 dB Contour By The City Of Naples And Collier County

The record does not support the NAA’s contention that the City of Naples and Collier County considered residential development within the DNL 60 dB contour to be incompatible at the time the Stage 2 ban was implemented. Indeed, the record evidence demonstrates that when the NAA adopted the Stage 2 ban, neither the City nor the County prohibited residential construction inside the DNL 60 dB contour.

In fact, both the City and the County recognized that development could be compatible above DNL 60 dB if certain non-restrictive measures were taken to mitigate the noise, such as sound attenuation. Local governmental decisions to approve noise sensitive development in the DNL 60 dB contour further undermine the NAA’s assertion that the City and County had determined that noise exposure was not compatible with residential development below DNL 65 dB. Consequently, we find the NAA’s assertion that it was “respecting the City of Naples and Collier County DNL 60 dB land use criterion” to be misleading. If the NAA was simply respecting the City and County criterion, the NAA could not have reasonably concluded, as it did in its Part 161 analysis, that sound attenuation of existing residences within the DNL 60 dB contour would not be an effective alternative to the Stage 2 ban. As discussed in more detail below, Collier County’s land use compatibility ordinance expressly states that residential construction within the DNL 60 dB contour is “generally compatible …” [242]

i. The City Of Naples

The NAA asserted, in its Part 161 Supplemental Analysis, that the City of Naples had “taken steps that establish DNL 60 dB as the level above which residential land use has been deemed not to be compatible with airport and aircraft operations.” [243] However, as acknowledged by the NAA, the City of Naples Ordinance No. 98-8165, upon which NAA based this assertion, required that the City Council provide general development site plan (“GDSP”) approval for residential construction within the DNL 60 dB contour. [244] The ordinance did not prohibit residential development within the DNL 60 dB contour.

Within weeks of the FAA’s final letter commenting on the NAA’s Part 161 analysis [245] and issuance of the instant Notice of Investigation, a representative of the City of Naples Planning Advisory Board (PAB) discussed the City’s consideration of the Lido Bay Resort proposal at an NAA board meeting. This proposal would have permitted the construction of a 58-unit three-story hotel/resort located between the DNL 60 dB and DNL 65 dB contours and in almost perfect alignment with Runway 05-23, just 2,700 feet away from the end of the runway. When the representative from the PAB was asked if the PAB considered residential development adjacent to the airport to be compatible with airport operations, the representative stated:

As you know again, we have entered into the Interlocal Agreement. We have formed an Airport Zoning Commission. The first meeting is scheduled for November 28[, 2001]. You all will be receiving a notice and agenda of that meeting. And one of the items that the commission will be addressing is the different types of land uses in proximity to the airport and what the appropriateness of those types of land uses are. So, I think that will be the process in which you will address the different land uses adjacent to the airport property.[246]

Moreover, the record shows that the Naples City Council approved residential development within the DNL 60 dB contour subsequent to enactment of Ordinance No. 98-8165. [247]

In 1999, the City issued building permits for the 156-unit Bayfront condominium development (selling for approximately $500,000 per unit). [248] These condominiums, which are within the DNL 60 dB contour, were constructed in the year 2000. [249] The development is located in an area the NAA refers to as “exceptionally noise-sensitive neighborhoods” and is located within a half mile from the end of runway 05-23. [250] In fact, this development accounts for a population of 320 out of a total impacted population count of 1,306 within the DNL 60 dB contour that the NAA now seeks to use to justify the ban. [251]

In 1998, the Naples City Council approved a rezoning petition for the River Point Marina Planned Development, also known as the Naples Bay Yacht and Boat Barn. City staff had recommended approval, provided that the petitioner provide an avigation easement to the Airport Authority because of the “proximity of the site to the airport.” [252] The development included, among other things, condominiums well within the DNL 60 dB contour and generally aligned with runway 05-23, in what the NAA defines as “exceptionally noise-sensitive neighborhoods.” [253] While the development never occurred, the fact remains that the City approved residential development within the 60 dB DNL contour after adoption of Ordinance No. 98-8165.

The Bayfront condominium development and the River Point Marina Planned Development were approved by the City within the DNL 60 dB contour despite the FAA’s approval of the Authority’s proposal to prevent construction within the DNL 60 dB contour. Specifically, in its “FAR Part 150 Study,” dated February 1997, the NAA advised the FAA that

it is important to create a buffer of compatible land use around the Airport. As such, another standard should be designated by the local land use planning agencies to ensure that residential and noise sensitive uses are not developed too close to the Airport. One possible standard is the 60 Ldn contour. . . . Applying the land use compatibility guidelines normally used for the 65 Ldn contour to [the] 60 Ldn contour should create an adequate area of compatible land use. [254]

The City’s actions establish that the City considered residential development to be compatible within the 60 dB DNL contour, with some land use mitigation measures, such as the acquisition of easements as was the case with the Bayfront condominium development. In fact, at the aforementioned NAA board meeting, the representative from the City’s PAB stated, in reference to the PAB process for recommending development to the City Council:

That is what the whole planning process is; you identify the problem, and then [find] significant ways to mitigate those incompatibilities. And if it is not, then your recommendation should be for denial. If you can make it a compatible land use through various measures, then I would believe your recommendation should be for approval. [256]

ii. Collier County

The NAA argues that Collier County adopted DNL 60 dB as the limit for compatible land use and amended its County Land Development Code (“CLDC”) accordingly. [258] However, the NAA also acknowledges that “[i]n Collier County, the Ordinance allows residential development with sound proofing requirements in the 70 and 65 LDN contour. . . . It also currently allows homes within the 60 LDN contour with a certain amount of soundproofing.” [259]

The CLDC was amended in June 2000 by Ordinance 2000-43 to, among other things, “provide development standards for land uses within prescribed noise zones associated with the normal operation of public use county airports.” [260] The amendment added a new Airport Noise Zone D, [261] which extends from the DNL 65 dB contour to the DNL 60 dB contour. Section 2.2.23.4.3 of the amended ordinance sets forth the sound level requirements (“SLR”) for buildings and structures, and Section 2.2.23.4.5 provides that “[n]o building or structure for which an SLR 25, SLR 30, or SLR 35 is required by appendix III of this amendment may be constructed … unless and until a building permit has been issued,” and “[n]o such permit shall be issued unless and until the requirements in appendix III are met… .” [262]

Appendix III of the amended ordinance requires that soundproofing requirements be met for residential structures located within the airport noise zones. It states that “NR” indicates that residential development is “Not recommended, the land use is not compatible with the identified noise zone. However, if the applicant chooses to develop within the identified noise zone, a sound level reduction (SLR) of 35 must be incorporated into the design and construction of the structure.” The designation of SLR-35, 30, or 25 indicates that “the land use is generally compatible, however, a sound level reduction (SLR) of 35, 30 or 25 must be incorporated into the design and construction of the structure.” [263]

Thus, a plain reading of the County’s amended ordinance indicates that the County permits construction in the DNL 60 dB contour with some required sound attenuation. Moreover, the County’s amended ordinance directly contradicts the NAA’s assertion that the County has determined the DNL 60 dB contour to be incompatible with residential development when the ordinance states that residential construction within the DNL 60 dB is “generally compatible ….,” with appropriate sound attenuation required for new construction and for alterations or repairs to exterior walls or ceilings of existing structures. [264] Also, since the sole effect of the ordinance is to reduce interior noise levels, the ordinance does not support the NAA’s argument for special consideration for outside noise levels in the Naples area, as discussed more fully below.

Consistent with our reading of the County’s amended noise ordinance, recent public statements by NAA staff indicate that the ordinance would permit continued residential construction in the DNL 60 dB contour. In May 2000, NAA Staff testified at a Collier County Planning Commission meeting. In its testimony, NAA Staff expressly stated that the purpose of the change from 65 to 60 dB as part of the Airport Overlay District was to protect “the same amount of land, and that protection, essentially provides for soundproofing and residential development within the noise zone, provides some restrictions if people do want to build in that area, and it also provides notification as well.” [265]

Finally, the NAA’s reliance on the County’s noise ordinance to justify the Stage 2 ban contradicts the express intent of the amendment of the ordinance. Specifically, Section 2.2.23.1.3 of the CLDC provides that it is “[t]he purpose and intent of these regulations … [t]o attempt to promote full utility of the public-use airports within Collier County… .” The Stage 2 ban degrades, rather than promotes, the utility of APF.

While even unequivocal action by the City and County to prohibit residential construction in the DNL 60 dB contour would not itself support a restriction on access to the airport, it is clear that neither the City nor the County had at the time the ban was implemented prohibited all residential within the DNL 60 dB contour that was used to define the land use compatibility goal the NAA used to justify the Stage 2 ban.

b. The NAA’s Contention That It Is Faced With Credible and Identifiable Threats of Liability From Property Owners

In the Part 161 Supplemental Analysis, the NAA asserts that it is faced with a “credible and identifiable threat of liability from property owners.” [266] The FAA has examined the material submitted by the NAA in support of this assertion and, as discussed more fully above, concludes that neither that material, nor the record generally, supports the NAA’s allegation that it has potential or actual noise liability exposure.

c. The NAA’s Use Of Complaints And SEL Data To Support The Stage 2 Ban

As discussed above, the NAA defined its “land use compatibility goal” in the 2000 NEM update and the Part 161 Study as “minimizing residential land within 60 dB DNL to the maximum extent feasible.” [267] The Part 161 Study stated that “[c]onsistent with this goal, the 2000/2005 NEM (Noise Exposure Map) Update used the 60 dB DNL contour as the basis for identifying potentially non-compatible land use . . . .” [268] The Part 161 Study also asserted, however, that “the basis for NAA action is supported by more than just the population within the NEM contours.” [269] Specifically, the Part 161 Study asserted that in addition to cumulative noise exposure, the “basis for community concern regarding noise impacts can be demonstrated” by reference to single event noise exposure and noise complaints. [270]

Accordingly, the NAA’s Reply to the Notice of Investigation asserts that in addition to “incompatible land use surrounding the Airport,” the NAA’s “noise problem also is reflected in . . . complaint data.” [271] The Reply also refers to complaint data and SEL data as support for the statement that “[t]he data in the Part 161 Study and related analyses makes [sic] clear that noise impacts are disproportionately attributable to the operations of Stage 2 aircraft.” [272]

We can appreciate the NAA’s desire and efforts to address noise complaints. As explained below, however, complaints and SEL data are not valid indicators of noncompatible land use. Moreover, the complaint and SEL data presented by the NAA do not, in any event, justify banning all Stage 2 aircraft from the Naples Airport. Thus, the NAA’s analyses of complaints and SEL data do not support a finding that the Stage 2 ban is reasonable under 49 U.S.C. § 47107(a) and Grant Assurance 22.

i. Complaints and SEL Data As Indicators Of Noncompatible Land Use

Complaints and SEL data are not valid indicators of noncompatible land use, [273] and thus do not support a finding of reasonableness under 49 U.S.C. § 47107(a) and Grant Assurance 22. Land use compatibility with airport noise is determined through assessment of objective data regarding community impacts from long-term noise exposure, expressed in terms of DNL. Congress, in ASNA, directed the FAA to address land use compatibility through a single system of noise measurement to be uniformly applied in measuring noise at airports and in surrounding areas for which there is a highly reliable relationship between projected noise and surveyed reactions of people to noise. [274] In 14 C.F.R. Part 150, the FAA adopted DNL to fulfill this statutory obligation. [275]

• Complaints

The attitudes of people are actually more important in determining their reactions to noise than their noise exposure level. Attitudes that affect an individual’s reactions include (1) apprehension regarding the safety of a noise source, (2) the belief that the noise is preventable, (3) awareness of nonnoise environmental problems, (4) a general sensitivity to noise, and (5) the perceived economic importance of the noise source.

The resultant variability in the way individuals react to noise makes it essentially impossible to predict with any accuracy how any one individual will respond to a given noise. When communities are considered as a whole, however, reliable relationships are found between reported annoyance and noise. [279]

This relationship between community annoyance and noise exposure levels “remains the best available source of predicting the social impact of noise on communities around airports . . . .” [280] As the Federal Interagency Committee on Noise (FICON) noted in its 1992 report, “the best available measure of [community annoyance] is the percentage of the area population characterized as ‘highly annoyed’ (%HA) by long-term exposure to noise of a specified level (expressed in terms of DNL).” [281]

If complaints could justify noise restrictions, a handful of people could effectively justify any noise restriction by consistently complaining. For example, the record reflects that 36 percent of all complaints filed with the NAA in the first quarter of 2000 came from eight families, and 154 calls came from two households. [282] In the last quarter of 1999, three families generated 27 percent of the complaints filed. [283]

We also note that when complaint data are placed on a map showing the airport runways and noise contours, the locale of complaints does not correlate with the area within the DNL 60 dB noise contour. In fact, an NAA handout for the April 2001 Collier County staff meeting indicates that most of the noise complaints are generated from residents outside the DNL 60 dB contour. [284] A comparison of the geographic distribution of aircraft noise complaints in Figures 10 to 12 of the Fidell Study to the pre-restriction DNL 60 dB contour, shows that the vast majority of complaints come from well outside the DNL 60 dB contour. [285] (See Figure 1, Complaint s v. DNL 60 dB Contour)

It also appears that the NAA itself has questioned the utility and efficacy of relying on complaints as a measure of its noise problem and as justification for the Stage 2 ban. In May 2000, when specifically asked by Collier County officials whether the change from 65 to 60 dB was going to be effective in stopping complaints, a NAA representative stated, “I wish…No, I don’t think this is going to reduce the complaints…” [286]

Accepting the NAA’s rationale that it is justified in banning Stage 2 aircraft because of complaints would have serious implications for the FAA. To accept the NAA’s use of complaint data, the FAA would have to agree that 0.7 complaints per day justify a ban of an entire class of aircraft [287] – all Stage 2 jets under 75,000 pounds. Given the very small number of complaints, this fact could be true at many airports in the national air transportation system. Allowing other airports to use the same complaint-based justification could result in airports banning 28 percent of the general aviation jet fleet in the United States based on an average of less than one complaint per day at each airport. [288]

• SEL Data

For example, in arguing that a significantly higher number of residents are impacted by the 85 dB SEL from a Stage 2 jet as compared to a Stage 3 jet, the NAA fails to indicate that all of the residents in the DNL 60 dB contour will experience 85 dB or greater SEL events from Stage 3 aircraft approximately 16 times more often than from Stage 2 aircraft, simply because there are more Stage 3 aircraft operating at the airport. [291]

Similarly, one event at 90 dB would be assessed as worse than 100 events at 89 dB. While the SEL metric can be used for certain purposes, [292] it does not reflect long-term noise impacts or annoyance reactions accurately, [293] making it an inaccurate and unreliable measure of community noise impacts. The NAA appears to understand that SEL is of limited use when it stated that the “analysis of SEL contours was not the basis for any of the conclusions reached in this report [Part 161 Study].” [294] Additionally, there is no accepted methodology for aggregating only the impacts of single events into some form of cumulative impact metric, and single event metrics do not describe the overall noise environment. [295] Moreover, there are no scientific data supporting the NAA’s implied assumption that a particular SEL contour, such as the 85 dB SEL contour, constitutes an “adverse effect.” [296]

ii. The NAA’s Use Of Complaints And SEL Data To Justify A Ban On All Stage 2 Aircraft

In its Reply to the Notice of Investigation, the NAA states:

The data in the Part 161 Study and related analyses makes [sic] clear that noise impacts are disproportionately attributable to the operations of Stage 2 aircraft. For example, if one uses a typical noise contour to measure impacts (85 dB SEL), a Lear 25 Jet (the most common Stage 2 aircraft at the Airport) adversely affects 70,000 people while a Lear 35 Jet (a Stage 3 jet) affects only 16,000 people. Part 161 Study (Exhibit 3) at 24-26 (depicting noise contours of the Lear 25 and Lear 35). Moreover, as summarized in the first report of the Part 161 Study:

1. Although Stage 2 aircraft operations account for less than one percent of aircraft operations at the Airport (3.15 operations per day in 2000 and 2.17 per day projected for 2005), they account for almost 40 percent of all noise complaints;
2. The rate of complaints associated with Stage 2 aircraft operations is 25 times that of complaints for Stage 3 aircraft operations and 250 times that of propeller-driven aircraft operations;
3. Stage 2 aircraft operations were over 50 times more likely to cause multiple noise complaints (more than one home) than Stage 3 aircraft operations and 800 times more likely than propeller-driven aircraft operations.

Id. at 27-28. [297]

Assuming, without conceding, the validity of the NAA’s analyses of complaints and SEL data, these analyses do not justify a ban on all Stage 2 aircraft. The analyses do not show—indeed, do not even purport to show—that “noise impacts” are “disproportionately attributable” to all Stage 2 aircraft. The SEL analysis shows only that a Lear 25 is noisier than a Lear 35; it does not show that all Stage 3 aircraft using the airport have “reduced noise impact” compared to all Stage 2 aircraft, nor that all Stage 2 operations have “significantly greater impact” than all Stage 3 operations. [302] Similarly, the analysis of complaint data does not show that all Stage 2 operations are “much more likely to annoy residents” than all Stage 3 operations.

Thus, even assuming the va lidity of the NAA’s analyses of complaints and SEL data, these analyses do not support a finding that the Stage 2 ban is reasonable under 49 U.S.C. § 47107(a) and Grant Assurance 22.

d. The NAA’s Analysis of Background and Ambient Noise Levels

The NAA argues that the low ambient noise levels in the City of Naples support, in part, its land use compatibility goal of minimizing residential land use within the DNL 60 dB. [303] In support of its assertion, the NAA presents an analysis conducted by NAA staff using portable noise monitors. The analysis was performed with the use of the L90 noise descriptor, which, according to the NAA, considers community reaction to noise in the context of the “residual” level. According to the NAA, the use of the L90 noise descriptor identifies corrections to be added to the DNL of “intrusive” noise to obtain “normalized” DNL, based on recommendations in an EPA report entitled “Community Noise.” The NAA supports its analysis by citing the EPA report as the most widely accepted basis for selection of normalizing factors.

According to the NAA, the EPA report recommends that the intruding noise be adjusted upward by five decibels for a “normal suburban community (not located near industrial activity)” and upward by ten decibels for a “quiet suburban or rural community (remote from large cities and from industrial activity and trucking).” The NAA asserts that the residential areas within the DNL 60 dB contour are not immediately adjacent to industrial activity, large cities, and any trucking activity, other than normal delivery vehicles. The NAA also asserts that the residual levels at 7 sites monitored by NAA staff within the DNL 60 dB contour are “extremely low,” generally between 40 to 50 dB, with one level of 39.4 and one of 53.4. Based on this information, the NAA concludes that the background noise levels clearly support a local compatibility criterion at least five decibels below the Federal DNL 65 dB compatibility guideline. [304]

As explained below, we do not find it reasonable for the NAA to restrict access to the airport on the basis of ambient noise levels.

i. The NAA’s Use Of Normalized DNL

The NAA’s applied use of a “normalization” technique to DNL lacks a clear scientific foundation, peer review, or a basis in current noise policy. In an early 1990’s technical review, FICON did not support the use of normalized DNL. The 1992 FICON report states that the concept of normalized DNL was never widely accepted within the scientific community. The report also states that there is insufficient scientific data to provide a basis for development of guidance on what level of difference between aircraft and ambient noise levels should trigger analysis of possible enhancement noise effects. When aircraft noise exposure levels approach 15 dB or more above the ambient, it is probable that enhancement occurs; however, it is difficult to predict the amount of increase in annoyance. [305]