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Notice

Clarification of the Term the day

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AGENCY:

National Park Service, Department of the Interior.

ACTION:

Notice.

SUMMARY:

This notice clarifies the meaning of the term the day as it is used in the National Park Service (NPS) definition of substantial restoration of natural quiet at Grand Canyon National Park (GCNP) pursuant to Public Law 100-91, the National Parks Overflights Act of 1987. It also helps to clarify the definition of substantial restoration of natural quiet recently the subject of litigation before the United States Court of Appeals, District of Columbia Circuit, in the case United States Air Tour Association v. Federal Aviation Administration (Grand Canyon Trust, Interveners). In this case, the Court declared that “* * * the Park Service is entitled to deference for its interpretation of its own definitions” (p. 19). The Court concluded “* * * the FAA's use of an “average annual day” for measuring “substantial restoration of Start Printed Page 63130natural quiet” appears inconsistent with both the Park Service's definition of the term and with the premise upon which that definition was based. * * * We must therefore remand this issue for further consideration” (p. 22).

Several interpretations of the meaning of the term the day have been advanced by various parties over the past few years, and the different interpretations have major implications for calculating the percentage of substantial restoration of natural quiet achieved at GCNP. This notice clarifies that the term the day in the definition of substantial restoration of natural quiet means any given day, every day, and provides guidance to the Federal Aviation Administration (FAA) concerning the appropriate definition of the day as used in the measurement of substantial restoration of natural quiet at GCNP. Clarification of this term will provide a benchmark for the future alternative dispute resolution process between the FAA and NPS. This clarification does not change the definition of substantial restoration of natural quiet.

ADDRESSES:

You may view a copy of this definition through the Internet at: http://www.nps.gov/​grca/​overflights.

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FOR FURTHER INFORMATION CONTACT:

Ken McMullen, Overflights and Natural Soundscape Program Manager, National Park Service, Grand Canyon NP, 823 N. San Francisco St., Suite B, Flagstaff, Arizona 86001. Telephone: (928) 779-2095, or by e-mail at Ken_McMullen@nps.gov.

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SUPPLEMENTARY INFORMATION:

Background

Public Law 100-91 called for the “substantial restoration of natural quiet and experience of the park” at GCNP. The NPS in its “Report on Effects of Aircraft Overflights on the National Park System” (submitted to Congress in September, 1994, and published in July, 1995) determined that “* * * substantial restoration requires that 50% or more of the Park achieve ‘natural quiet’ (i.e., no aircraft audible) for 75-100 percent of the day” (p. 182). Although the context of this definition suggested that the day implied each day, every day, or any given day (terms considered to mean the same thing in this context), the term was not further clarified in this report. However, the NPS analysis in the report was consistent with any given day.

In its “Review of Scientific Basis for Change in Noise Impact Assessment Method Used at Grand Canyon National Park” (2000), the NPS provided definitions of terms used, as well as rationale, for its noise impact assessment methods. In this review the NPS defined substantial restoration of natural quiet to be “* * * a threshold not to be exceeded on any given day. * * *” (p. 16).

The term the day in the definition of substantial restoration of natural quiet was recently the subject of litigation before the United States Court of Appeals, District of Columbia Circuit, in the case, United States Air Tour Association v. Federal Aviation Administration (Grand Canyon Trust, Intervenors). In this case, the Court declared that “* * * the Park Service is entitled to deference for its interpretation of its own definitions” (p. 19). The Court concluded “* * * the FAA's use of an “average annual day” for measuring “substantial restoration of natural quiet” appears inconsistent with both the Park Service's definition of the term and with the premise upon which that definition was based.* * * We must therefore remand this issue for further consideration” (p. 22).

Clarification of the Term

When used in the definition of substantial restoration of natural quiet, the day means any given day; that is, following the mandate of Public Law 100-91, natural quiet must be substantially restored at GCNP on any given day of the year. As further clarification, to achieve substantial restoration of natural quiet, 50% or more of the park must achieve “natural quiet” (i.e., no aircraft audible) for 75-100 percent of any given day.

Clarification also provides the FAA the guidance from the NPS concerning the appropriate definition of this term and assists in the determination of how to address aircraft noise as discussed in the Department of Transportation/FAA Federal Register Notice of February 27, 2003, Modification of the Dimensions of the Grand Canyon National Park Special Flight Rules Area and Flight Free Zones (Federal Register/Vol. 68, No. 39, pgs. 9496-9498). Clarification of this term will provide a benchmark for the future alternative dispute resolution process between the FAA and NPS.

Significance of using any given day vs. other possible interpretations: Computer modeling of substantial restoration of natural quiet for previous FAA regulations followed FAA procedures and was based upon the number of air tour operations on an “average annual day,” as determined by dividing the year's total operations by 365 days. The most recent computer modeling was done as a part of the Supplemental Environmental Assessment (Feb. 2000) accompanying the FAA final rule, “Commercial Air Tour Limitations in the Grand Canyon National Park Special Flight Rules Area” (65 FR 17,708). The modeling used the FAA's Integrated Noise Model (INM) and was based on air tour operations reported for the 12-month period May 1, 1997 through April 30, 1998. The model indicated that using the “peak day” (any given day) definition, substantial restoration would not occur during the high visitation season, and that restoration of natural quiet would occur in 19% of the park. In contrast, modeling on the “average annual day” indicated that substantial restoration of natural quiet would occur in 44 % of the park. Thus, when using an “average annual day” standard, substantial restoration of natural quiet would not be achieved during the five summer months and portions of the shoulder seasons'times when the majority of the people visit the park. As the Court observed, “* * * the use of an annual average does not correspond to the experience of the Park's actual visitors. People do not visit the Park on ‘average days’, nor do they stay long enough to benefit from averaging noise over an entire year. For the typical visitor, who visits the Grand Canyon for just a few days during the peak summer season, the fact that the Park is quiet ‘on average’ is cold comfort” (p. 21).

In summary, the National Parks Overflights Act of 1987 made clear that the visitors to GCNP are entitled to have the opportunity to experience substantial restoration of natural quiet. The Act did not limit that opportunity to only a portion of the park visitors or a portion of the year. The NPS, in its report to Congress, stated that such restoration would be for the day and, in its “Review of Scientific Basis for Change in Noise Impact Assessment Method * * *”, the NPS further stated that it intended this to be “a threshold not to be exceeded on any given day.” Thus, as suggested by the United States Court of Appeals, District of Columbia Circuit, the NPS clarifies the day to mean any given day. On each and every day, visitors to GCNP will have the opportunity to experience natural quiet, that is, 50% of the park naturally quiet 75-100% of the time.

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Dated: May 15, 2003.

Michael D. Sunder,

Acting IMR-Regional Director.

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[FR Doc. 03-28113 Filed 11-6-03; 8:45 am]

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