[Federal Register Volume 59, Number 52 (Thursday, March 17, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-6216]


[[Page Unknown]]

[Federal Register: March 17, 1994]


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Part IV





Department of Transportation





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Federal Aviation Administration



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14 CFR Parts 91 and 95



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Department of the Interior





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National Park Service



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36 CFR Part 1, et al.




Overflights of Units of the National Park System; Proposed Rule
DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 91 and 135

DEPARTMENT OF THE INTERIOR

National Park Service

36 CFR Parts 1, 2, 3, 4, 5, 6 and 7

[Docket No. 27643; Notice No. 94-4]

 
Overflights of Units of the National Park System

AGENCY: National Park Service (NPS), DOI and Federal Aviation 
Administration (FAA), DOT.

ACTION: Advanced notice of proposed rulemaking (ANPRM).

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SUMMARY: This notice seeks public comment on general policy and 
specific recommendations for voluntary and regulatory actions to 
address the effects of aircraft overflights on national parks.
    On December 22, 1993, Transportation Secretary Federico Pena and 
Interior Secretary Bruce Babbitt announced the formation of an 
interagency working group to explore ways to limit or reduce impacts 
from overflights on national parks. Secretary Babbitt and Secretary 
Pena concur that increased flight operations at the Grand Canyon and 
other national parks have significantly diminished the national park 
experience for park visitors, and that measures can and should be taken 
to preserve a quality park experience for visitors. The Secretaries see 
the formation of the working group, and the mutual commitment to 
addressing the impacts of park overflights, as the initial steps in a 
new spirit of cooperation between the two departments.
    National parks are unique national resources that have been 
provided special protection by law. The National Park Service (NPS) and 
the Federal Aviation Administration (FAA) recognize that excessive 
noise from commercial air tours and other flights over units of the 
national parks system can interfere with NPS efforts to achieve a 
natural park experience for visitors and to preserve other park values. 
Through the interagency working group, the NPS and FAA will cooperate 
in developing measures to resolve current noise impacts and prevent 
potential future impacts from overflights at national parks. The 
purpose of this ANPRM is twofold. First, the ANPRM addresses 
overflights of Grand Canyon National Park and national parks in the 
State of Hawaii, with particular emphasis on overflights by commercial 
tour operators. Second, the ANPRM solicits policy views and 
recommendations on more general issues as part of an effort to form a 
comprehensive policy on preventing, minimizing, or eliminating impacts 
of aircraft overflights.
    This notice presents options that may be considered as means to 
minimize the adverse effects of commercial air tour operations and 
other overflights on units of the national park system, and seeks 
public comments and suggestions on voluntary and regulatory actions to 
deal with noise and other overflight issues that may affect national 
parks.

DATES: Comments on this ANPRM must be received on or before June 15, 
1994.

ADDRESSES: Comments on this advance notice should be mailed, in 
triplicate, to: Federal Aviation Administration, Office of Chief 
Counsel, Attention: Rules Docket (AGC-200), Docket No. 27643, 800 
Independence Avenue, SW., Washington, DC 20591. Comments delivered must 
be marked Docket No. 27643. Comments may be examined in room 915G 
weekdays between 8:30 a.m. and 5 p.m., except on Federal holidays.

FOR FURTHER INFORMATION CONTACT: David L. Bennett, Office of Chief 
Counsel, AGC-600, Federal Aviation Administration, 800 Independence 
Avenue, SW., Washington, DC 20591, telephone (202) 267-3473, or Michael 
M. Tiernan, Office of the Solicitor, Department of Interior (DOI), 18th 
and C Streets, NW., Washington, DC 20240, telephone (202) 208-7597.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in this advance 
notice of proposed rulemaking by submitting such written data, views, 
or arguments as they may desire. Comments relating to the policy, 
environmental, energy, federalism, or economic impact that might result 
from considering the options in this advance notice are also invited. 
Comments should identify the regulatory docket number and should be 
submitted in triplicate to the Rules Docket address specified above. 
All comments received on or before the specified closing date for 
comments will be considered by NPS and FAA before taking action on this 
advanced notice of proposed rulemaking. All comments received will be 
available, both before and after the closing date for comments, in the 
Rules Docket for examination by interested persons. Commenters wishing 
the FAA or NPS to acknowledge receipt of their comments submitted in 
response to this notice must include a preaddressed, stamped postcard 
on which the following statement is made: ``Comments to Docket No. 
27643.'' The postcard will be date stamped and mailed to the commenter.

Availability of ANPRM

    Any person may obtain a copy of this ANPRM by submitting a request 
to the Federal Aviation Administration, Office of Public Affairs, 
Attention: Public Inquiry Center, APA-200, 800 Independence Avenue, 
SW., Washington, DC 20591, or by calling (202) 267-3485. Communications 
must identify the notice number of this ANPRM.

Background

    The management of the national park system is guided by the 
Constitution, public laws (Pub. L.), proclamations, executive orders, 
rules and regulations, and directives of the Secretary of the Interior 
and the Assistant Secretary for Fish and Wildlife and Parks. The Act of 
August 25, 1916, otherwise known as the NPS Organic Act, established 
the NPS and serves as the touchstone for national park system 
management philosophy and policy. The Act created the NPS to promote 
and regulate national parks, monuments, and reservations in accordance 
with the fundamental purpose of said parks, monuments, and 
reservations, which is ``to conserve the scenery and the natural and 
historic objects and the wildlife therein and to provide for the 
enjoyment of the same in such manner and by such means as will leave 
them unimpaired for the enjoyment of future generations.'' (16 U.S.C. 
1). Subsequent legislation further states that any authorized activity 
``shall not be exercised in derogation of the values and purposes'' of 
a park area or the national park system, except as may have been or 
shall be directly and specifically provided by Congress. (16 U.S.C. 1a-
1).
    Thus, ``unimpairment'' is joined by a responsibility to avoid 
derogation not only of the purposes of a park area but also the values 
for which the national park system and its individual units have been 
established.
    In 1987, the Congress enacted the NPS Overflights Act because it 
recognized that aircraft overflights can adversely affect national 
parks. The Act specifically found that noise associated with aircraft 
overflight at the Grand Canyon National Park was causing ``a 
significant adverse effect on the natural quiet and experience of the 
park and current operations at the Grand Canyon National Park have 
raised serious concerns regarding safety of park users.'' (Pub. L. 100-
91, section 3(a)). The Act mandated a number of studies related to the 
effects of overflights on parks. The studies have taken longer than was 
originally anticipated because many of the issues with which they deal 
are on the cutting edge of technical and scientific capability. 
Measuring degrees of quiet and perception of quiet is very different 
from measuring amounts of noise. Since the Overflights Act was passed, 
the adverse effects associated with the numbers and extent of 
commercial air sightseeing tours have continued to expand.
    The general and over-arching responsibilities for park management 
by NPS may be modified by specific direction in individual enabling 
legislation and proclamations. The individual statutes and 
proclamations for some units of the national park system make it clear 
that the units were established to provide visitors with natural quiet, 
an opportunity for solitude, and other attributes that are not 
necessarily compatible with the noise of commercial air tour 
sightseeing flights. Some people simply find commercial sightseeing 
tours over parks inappropriate and incompatible with protection of 
certain park values and resources. On the other hand, a commercial air 
tour may provide an opportunity for people to see some park resources 
in ways not otherwise attainable.
    As is pointed out in the Management Policies (NPS 1988):

    Over the years, legislative and administrative actions have been 
taking place that have brought some measure of change to these 
components of our national parks. Such actions impact park 
resources, yet they are not necessarily deemed to have impaired 
resources for the enjoyment of future generations. Whether an 
individual action is or is not an ``impairment'' is a management 
determination based on NPS policy. In reaching it, the manager 
should consider such factors as the spatial and temporal extent of 
the impacts, the resources being impacted and their ability to 
adjust to those impacts, the relation of the impacted resources to 
other park resources, and the cumulative as well as the individual 
effects.

    Both physical resources, such as wildlife or geologic features or 
cultural resources, and intangible values, such as natural quiet 
solitude, and the experience of wilderness, can be impaired.

Impacts to Parks

    In the case of commercial air tour sightseeing flights operating 
over and near units of the national park system, the NPS believes that 
significant park resources are being impaired in some units. Managers 
of almost one-third of national park system units perceive a problem 
with some aspect of already existing aircraft overflights. The sound of 
aircraft is regarded as the primary impact. A survey of park managers 
confirmed that mechanical noise is among the more serious problems in 
parks and aircraft noise is the most prominent among these. The 
perception of noise and adverse effects in units of the national park 
system may be related to the fact that parks tend to be quieter places 
in general and that typical sources of noise found in urban and 
suburban settings are absent in most parks. The potential exists for 
impairment of park resources and values by the noise and visual 
intrusion associated with commercial air tour/sightseeing operations in 
other units where the air tour sightseeing industry is not yet 
established or developed.
    Given the changes in our population distribution, patterns of use 
of our national parks, and other factors related to transportation, it 
is no longer sufficient for park managers to consider strategies and 
actions solely within park boundaries to protect parks and their 
resources. Overflights are a case in point. Most overflights of units 
of the national park system begin and end at airports outside parks; 
the attractions the overflights offer are the resources of the parks 
themselves. Technically, the park overflight passenger is not a park 
visitor even though there may be significant adverse effects from noise 
on the park. In recognition of this fact, the FAA and the NPS are 
working more closely to use the FAA's plenary authority for regulation 
of aviation in support of NPS management objectives.

FAA Authorities

    The FAA has broad authority and responsibility to regulate the 
operation of aircraft and the use of the navigable airspace, and to 
establish safety standards for and regulate the certification of 
airmen, aircraft, and air carriers. (Federal Aviation Act of 1958, as 
amended (FAAct), Section 307(a) and (c); Title VI.) The FAAct provides 
guidance to the Administrator in carrying out this responsibility. 
Section 102 of the FAAct states that the Administrator will consider 
the public interest to include among other things, regulation for 
safety and efficiency of both civil and military operations, promotion 
of the development of civil aviation, fulfillment of the requirements 
of national defense, and operation of a common system of air traffic 
control for civil and military aircraft. Section 104 provides to each 
citizen of the United States a public right of transit through the 
navigable airspace of the United States. Section 305 directs and 
authorizes the Administrator to encourage and foster the development of 
civil aeronautics and air commerce. Section 306 requires the 
Administrator in exercising his authority, to give full consideration 
to the requirements of national defense, commercial and general 
aviation, and to the public right of freedom of transit through the 
navigable airspace.
    The FAA's authority is not limited to regulation for aviation 
safety, efficiency, and development. Subsection 307(c) of the FAAct 
provides that FAA air traffic rules and flight regulations may be 
adopted ``for the protection of persons and property on the ground.'' 
The FAA considers this protection to extend to environmental values on 
the surface as well as to the safety of persons and property. Section 
611 of the FAAct, ``in order to afford present and future relief to the 
public health and welfare from aircraft noise,'' directs the 
Administrator to adopt regulations ``as the FAA may find necessary for 
the control and abatement of aircraft noise,'' including application of 
such regulations to any of the various certificates issued under Title 
VI. Finally, it is the general policy of the Federal government that 
the FAA, like other agencies, will exercise its authority in a manner 
that will enhance the environment, and that the FAA will make a special 
effort to preserve the natural beauty of public park and recreation 
lands, wilderness areas, and wildlife refuges. Section 101 of the 
National Environmental Policy Act of 1969, as amended, 42 U.S.C. 4321; 
Section 4(f) of the Department of Transportation Act, 49 U.S.C. 303; 
and Executive Order 11514, as amended by Executive Order 11991. In 
addition, the DOT has further authority to regulate services by 
commercial operators.

Fees

    The Budget Reconciliation Act of 1993 (Pub. L. 103-66, August 10, 
1993) amended Section 4 of the Land and Water Conservation Fund Act of 
1965 (16 U.S.C. 4601-6a) requiring the NPS to impose a commercial tour 
use fee on each vehicle entering a unit of the national park system, 
that presently charges an entrance fee, for the purpose of providing 
commercial tour services.
    In addition to surface transportation, this commercial use fee 
applies to aircraft entering ``the airspace of units of the National 
Park System'' identified in sections 2(b) and 3 of Public Law 100.91 
(Grand Canyon National Park and Haleakala National Park) as well as any 
other park areas where the level of commercial aircraft services are 
equal to or greater than these two identified areas.
    The actual fees established by the legislation are as follows:
     $25 per vehicle with a capacity of 25 people or less, and
     $50 per vehicle with a capacity greater than 25 people. 
The legislation also gives the Secretary the authority to make 
reasonable adjustments to these recommended commercial tour fees. 
Currently, there are no additional NPS areas that charge entrance fees, 
and also have a level of commercial aircraft services equal or greater 
to Grand Canyon or Haleakala National Parks. As a result of the 
legislation, the NPS will need to monitor the number of air tour 
operations over the affected parks.

Grand Canyon National Park

    At Grand Canyon, 42 companies offer aerial tours operating from 
five states (Arizona, California, Nevada, Utah, and New Mexico). These 
companies provide air tours of the Grand Canyon to about 750,000 people 
and generate revenues in excess of $100 million. During peak summer 
months, the number of tours exceeds 10,000 each month. On June 5, 1987, 
the FAA issued Special Federal Aviation Regulation (SFAR) No. 50-1 (52 
FR 22734, June 15, 1987) which provided rules to enhance safety of 
overflight operations in the vicinity of the Grand Canyon National 
Park. Section 3 of Public Law 100-91 required the Secretary of the 
Department of the Interior (DOI) to submit to the FAA Administrator 
recommendations for the protection of resources in the Grand Canyon 
from adverse impacts associated with aircraft overflights. The 
recommendations were to provide for substantial restoration of the 
natural quiet and experience of the Grand Canyon. With limited 
exceptions, the recommendations were to prohibit the flight of aircraft 
below the rim of the Canyon and to designate zones that were flight 
free except for purposes of administration of underlying lands and 
emergency operations.
    Public Law 100-91 further required the Secretary of the Interior to 
prepare and issue a final plan for the management of air traffic above 
the Grand Canyon. In December 1987, the DOI submitted recommendations 
to the FAA for an aircraft management plan at the Grand Canyon. The 
recommendations included both rulemaking and non-rulemaking actions. On 
May 27, 1988, the FAA issued SFAR No. 50-2 (53 FR 20264, June 2, 1988) 
which revises the procedures for operation of aircraft in the airspace 
above the Grand Canyon. The rule implements the preliminary 
recommendations of the Secretary of the Interior for an aircraft 
management plan at the Grand Canyon with some modifications that the 
FAA initiated in the interest of aviation safety. SFAR No. 50-2 
establishes a Special Flight Rules Area from the surface to 14,500 feet 
above mean seal level (MSL) in the area of the Grand Canyon. The SFAR 
prohibits flight below a certain altitude in each of five sectors of 
this area with some exceptions. The SFAR also establishes flight free 
zones from the surface to 14,500 feet msl above large areas of the 
park. The ``flight free zones'' cover virtually all of the visitors to 
the North and South Rims and about 90 percent of backcountry users. The 
SFAR also provided special routes for commercial tour operators and 
transient operators through the canyon area, Commercial air tour 
operations are required to be conducted as air taxi and commercial 
operations under part 135 with stringent requirements including special 
operations specifications for Grand Canyon. The NPS believes the SFAR 
has been successful in limiting some noise-associated adverse impacts 
to the park but most, if not all, of the gain has been, or may be, lost 
as a result of the exponential growth in numbers of flights over the 
canyon.
    Virtually every class of visitor activity at Grand Canyon National 
Park is limited or controlled in some way by the NPS to insure that 
there will be no derogation or impairment of resources and values. Each 
raft trip on the Colorado River through Grand Canyon National Park must 
have a permit and the number of permits is limited for both commercial 
and private rafters. For some private raft trips, a permit may take 4 
or 5 years to obtain. Each over-night visitor in the backcountry must 
have a backcountry permit; the demand for such permits far exceeds the 
supply. The waiting list for trips by mule into the inner canyon runs 
into years for some times of the year. There are a limited number of 
hotel rooms in the park and there are a limited number of parking 
spaces. In contrast, the commercial air tour sector has experienced 
unlimited growth at Grand Canyon National Park in the last 10 years. 
This is so even though Congress found noise associated with overflights 
to be significantly and adversely affecting the park in the 1987 
Overflights Act. In addition, the NPS believes there is ample evidence 
that the uncontrolled and unregulated growth in this sector is in 
derogation of the resources and values of the park. NPS studies to that 
effect will be published later this year.

Grand Canyon--Actions to Date

    Public Law 100-91 directed the DOI to substantially restore 
``natural quiet'' to the Grand Canyon National Park. Public Law 100-91 
also required a study of aircraft noise impacts at a number of national 
parks and imposed flight restrictions at three parks: Grand Canyon 
National Park, Yosemite National Park in California, and Haleakala 
National Park in Hawaii. Public Law 100-91 also required the DOI to 
conduct a study, with the technical assistance of the Secretary of 
Transportation, to determine the proper minimum altitude to be 
maintained by aircraft when flying over units of the national park 
system. The research was to include an evaluation of the noise levels 
associated with overflights. Before submission to Congress, the DOI is 
to provide a draft report (containing the results of its studies) and 
recommendations for legislative and regulatory action to the FAA for 
review. The FAA is to notify the DOI of any adverse effects these 
recommendations would have on the safety of aircraft operations. The 
FAA is to consult with the DOI to resolve these issues. The final 
report must include a finding by the FAA that implementation of the DOI 
recommendations will not have adverse effects on the safety of aircraft 
operations, or, in the alternative, a statement of the reasons why the 
recommendations will have an adverse effect. The DOI expects to 
complete the report by early summer, 1994.

Haleakala and Hawaii Volcanoes National Parks

    The national parks in Hawaii--Hawaii Volcanoes and Haleakala--have 
similar problems with commercial air sightseeing tours, principally 
noise associated with helicopters. The FAA held a series of public 
hearings in January 1994 to elicit public comments and recommendations 
for regulatory or policy action related to overflights, including their 
effects on parks. There are 9 tour operators on the island of Hawaii, 
and there are approximately 60 commercial air tours a day over Hawaii 
Volcanoes National Park. At Haleakala, which was established to 
preserve resources in ``natural condition,'' (39 Stat. 432, section 4), 
seven companies based on the island of Maui offer helicopter tours. On 
clear days, helicopters fly over the park during all hours of daylight 
so that helicopter noise is audible over 30 minutes of every daylight 
hour (personal communication, Haleakala National Park). Interpretive 
talks, wildlife observations and censuses, ceremonies, and other normal 
activities are interrupted by air tour overflights. The NPS recognizes 
that the commercial air tour industry is important to the economy of 
Hawaii but also believes that the tourism industry benefits from the 
continued NPS protection of the superlative resources of its national 
parks, unimpaired.

Hawaii--Actions to Date

    The majority of flights conducted by helicopter companies in Hawaii 
are commercial air tour/sightseeing operations. Both the NPS and FAA 
have received numerous complaints of commercial air sightseeing tour 
flights over residential communities, national parks, wildlife refuge 
areas, State natural reserve areas, sanctuaries and areas of 
significant historic or cultural value. Issues raised by the growth of 
air tour sightseeing activity and the associated increase in the number 
of flights conducted over a given area include aircraft noise, flight 
noise, flight safety, and airport site constraints near scenic areas. 
It may be necessary to determine if there are thresholds of adverse 
effects that have been met in terms of impacts to the parks.
    The FAA has taken several steps to address the overflight issues in 
Hawaii. In 1986, the FAA conducted a study of helicopter sightseeing 
operations in Hawaii. As a result of that study, recommendations were 
made to the State and to operators in Hawaii to improve safety and 
community relations. Also in 1986, the FAA conducted a joint study with 
the State on heliport and airport access. A result of that study was a 
helicopter operating plan for Hawaii. Numerous meetings have since been 
held with NPS personnel, industry, and local communities, including 
four public meetings conducted in January 1994.

Impacts to Parks and Their Resources

    At some parks, including Grand Canyon National Park, Hawaii 
Volcanoes National Park, and Haleakala National Park, the temporal and 
spatial extent of commercial air tours are, in the judgment of NPS 
managers, impairing park resources and visitor experience. While the 
NPS and FAA are interested in evaluating potential solutions to the 
problems at these parks, they are also seeking solutions that will make 
it possible to avert problems in the future throughout the national 
park system as have developed at these parks.

Cultural Resources

    Very limited information is available on the response of structures 
to subsonic aircraft and helicopters. The greatest potential risk to 
historic structures and cultural resources in units of the national 
park system is from helicopters. The noise characteristics of 
helicopters are such that they tend to excite nearby structural 
elements at their resonance frequency, causing low frequency 
vibrations, rattle, and in some cases, damage. The sound pressure is 
greatest at structures in the plane of the main rotor, such as could be 
the case for a helicopter approaching cliff dwellings. When 
representative cultural resources were reviewed for probability of 
damage, most were found to be at some risk from commercial air 
sightseeing tours. Mesa Verde (Colorado) and Canyonlands National Parks 
(Utah), among others, protest fragile prehistoric stone and adobe 
structures, including granaries and cliff dwellings, as well as 
associated cultural materials that are susceptible to damage from 
helicopter-induced noise and rotor wash. The cultural and spiritual 
values commemorated in units of the national park system like San 
Antonio Missions National Historical Parks and the battlefields of the 
Civil War can be wholly lost by frequent and intrusive commercial air 
sightseeing tour overflights.
    As further examples of areas impacted by aircraft overflights, 
Mount Rushmore National Memorial and the Statue of Liberty National 
Monument are cultural icons that can be adversely affected in 
significant ways be commercial air tour overflights. At the Statue of 
Liberty, an impending aircraft service would take off and land 
helicopters from a floating raft less than one-half mile from the 
statue. This service would be added to two existing commercial 
sightseeing helicopter operators that account for 115 flights per day 
and a service that operates four fixed-wing aircraft on air tours. 
Similarly, the experience of Mount Rushmore National Memorial for the 
visitors on the ground can be irretrievably lost as a consequence of 
the aircraft flights close to memorial.

Wildlife Effects

    A comprehensive study of the adverse effects of commercial air 
sightseeing tours on wildlife in parks has yet to be concluded. Studies 
to date indicate that aircraft can be associated with stress responses 
on a number of animals, including migratory birds. Endangered species, 
like the grizzly bear in Glacier National Park, can be harassed by 
commercial air tour operators unaware of the potential adverse effects 
of flying too close to them. Other mammals like desert bighorn sheep, 
dear, and elk that have found refuge in parks can be panicked and 
stressed by low-flying aircraft, as well. No studies that evaluate 
long-term effects on wildlife, including population level impacts of 
commercial air sightseeing tours, have been conducted. As with any 
potential impact associated with activities in parks, the NPS policy is 
to err on the side of resource protection until conclusive information 
is available that would indicate otherwise.

Assessing Noise Impacts

    The FAA is working with the NPS to define acceptable noise levels 
as the basis for any proposed limitations on aircraft overflights. This 
process involves identifying areas with the highest levels of noise 
sensitivity. Highly sensitive areas potentially would be subject to 
lower noise limits than would apply to other areas with higher ambient 
noise levels, based on resource values, types of use, or other factors. 
Depending on local conditions, alternative approaches may be employed 
in different areas to achieve the same noise goal.
    Current FAA policy and guidelines designate the yearly day-night 
average sound level (DNL) as the single noise metric for measuring 
aviation impacts on people in and around airports. This traditional 
metric alone may not be appropriate for assessing aviation noise 
impacts in parks and wilderness areas. Three supplemental metrics other 
than DNL are proven and appear particularly suitable for site-specific 
assessments. These are Equivalent Sound Level (Leq), Sound 
Exposure Level (SEL) and Time Above a dBA Threshold (TA). Additionally, 
defining a change of 5 dB as significant at any initial DNL level may 
be appropriate for specifying further noise analysis in parks and 
wilderness areas.
    The ongoing NPS studies have identified two potential (dose-
response relationships that also may be appropriate for assessing 
aircraft noise impacts. These are ``Annoyance vs. Percent Time Heard'' 
and ``Interference with Quiet vs. Percent Time Heard.'' These 
relationships are preliminary and must be subjected to rigorous 
analysis for further determination of their potential application.

Policy Considerations

    In reviewing potential alternatives for achieving NPS and FAA 
purposes, the FAA has considered a number of measures within its 
authority under the FAAct that would have the potential to address the 
problems identified by the NPS. In determining whether a particular 
action would be beneficial for this purpose and otherwise feasible, the 
FAA and NPS must take into account a number of legal and policy 
considerations.
    The action, if regulatory, must be consistent with Administration 
rulemaking principles as set forth in Executive Order 12866. These 
principles include requirements that regulations be drafted in the most 
cost-effective manner to achieve the objective; that regulations be 
based on the best reasonably obtainable scientific, technical, 
economic, and other information concerning the need for and 
consequences of the action to be taken; and that regulations be 
tailored to impose the least burden on society, including individuals, 
businesses, and communities, consistent with obtaining the regulatory 
objective.
    The action must have no adverse effect on aviation safety. The 
action should have the minimum possible adverse effect on the 
efficiency of air navigation, consistent with the regulatory objective, 
and should not unduly burden interstate commerce. It must also meet NPS 
requirements for protecting resources, assuring that there is no 
impairment, and that there is no derogation, to park resources and 
values.
    The action should focus directly on the problem rather than 
indirectly. For example, if the issue is the adverse impacts of 
overflights of a unit of the national park system, then the agency 
action will address those overflights directly, rather than seek to 
influence them through regulation of takeoffs and landings at a nearby 
airport.

Options for Evaluation

    The FAA and NPS believe that each of the following measures may 
have some utility, in certain circumstances, as a measure to mitigate 
the adverse effects of commercial air sightseeing tour overflights of 
units of the national park system. Inasmuch as some of the measures 
have not been used before, neither the FAA nor NPS has concluded that 
such actions would meet the legal and policy considerations summarized 
above, and specific comment is requested on the benefits, costs, and 
impacts of each.

Voluntary Measures

    Voluntary, non-regulatory measures that mitigate noise impacts 
would impose the minimum burden on operators and can be effective. An 
example is the recommended minimum altitude of 2,000 feet above ground 
level described in FAA Advisory Circular 91-36C, which is honored by 
most transient operators. Another option would be expansion of the 
existing Interagency Agreement among the FAA, the NPS, the Fish and 
Wildlife Service, and the Bureau of Land Management. Through that 
agreement the proponents agree to assess severe situations where impact 
of aircraft operations upon human, cultural, or natural resources are 
sufficiently serious to warrant consideration of site-specific action 
by the FAA to minimize or eliminate the causes of such problems. 
Expansion of the Interagency Agreement could provide for additional 
non-regulatory actions by the agencies to mitigate overflight impacts. 
The agencies seek comments on the relative merits of voluntary measures 
generally, and specific suggestions for other voluntary measures not 
currently used by the FAA or NPS.

Grand Canyon Model

    One option is to follow a model similar to that in use at Grand 
Canyon, with extensive regulation of airspace, routes, and minimum 
altitudes as discussed separately below. Such an approach may not 
adequately consider the fact that the total number and frequency of 
flights, and the steady growth in numbers of flights, are not currently 
addressed under that regulatory framework.

Prohibition of Flights During Flight-Free Time Periods

    A prohibition could be established on use of some or all of the 
airspace above parks at certain times; e.g., 1 hour per day, 1 day per 
week, or 2-4 weeks per year. The ``quiet times'' would be published 
well in advance both for air tour operator scheduling and for planning 
by park visitors. In terms of noise mitigation, non-flying quiet 
periods would present an unusual approach to the balance between air 
access and the interest in restoring some degree of the natural quiet 
in Grand Canyon National Park. At some cost in inconvenience and lost 
business for air tour operators and temporarily reduced access to air 
tours for their passengers, the park would enjoy a virtual absence of 
aircraft noise in sensitive areas for specific periods. The agencies 
specifically request comment on the potential efficacy of these 
approaches in meeting FAA and NPS goals.

Altitude Restrictions

    SFAR No. 50-2 at Grand Canyon currently specifies a minimum 
altitude for flight over the different areas of the park as high as 
14,500 feet msl. It also specifies minimum altitudes for operation in 
the flight corridors between the flight-free zones. Different altitudes 
are specified for transient general aviation operations and for air 
tour operators, to separate high-frequency tour flights from one-time 
transient flights. Different altitudes are also specified for fixed-
wing aircraft and helicopter tour flights, for safety and efficiency 
reasons. The tour operation altitudes are at canyon rim level or above 
(although some are slightly below the minimum altitude requested by NPS 
as ``rim level'' in 1987). A relatively high minimum altitude in a 
particular area limits access to the airspace over that area by many 
general aviation aircraft because of performance limitations. 
Generally, noise mitigation is achieved through higher minimum 
altitudes because the greater the slant-range distance from an aircraft 
to a point on the surface, the lower the sound level on the surface 
from aircraft noise. However, this mitigation can be offset or reversed 
based on attenuation factors such as hills, heavily wooded areas, and 
``soft ground'' terrain.

Flight Free Zones/Flight Corridors

    SFAR No. 50-2 at Grand Canyon now describes specific ``flight-
free'' zones to an altitude of 14,500 feet msl above the park. The 
remaining airspace is defined as corridors for operations over the park 
by both general aviation and commercial air tour operators. Impact 
mitigation is achieved through specifying corridors for flight over the 
park that assure there are no overflights of large areas of the park 
below the current minimum altitude of 14,500 feet msl. The current 
corridors and flight-free zones could be amended to address concerns 
about effects on particular areas of the park.

Restrictions on Noise Through Allocation of Aircraft Noise 
Equivalencies

    A noise budget is a mechanism for limiting total aircraft noise 
impact on the park by assigning each air tour operator an individual 
limit on noise impact. This would allow individual air tour operators 
the flexibility to decide what combination of equipment and flight 
frequency they will use to attain the target noise level. The noise 
budget would apply only to air tour sightseeing operators and not to 
transient general aviation operations. The noise budget concept assumes 
that the FAA and NPS could determine (1) the acceptable amount of 
aircraft noise exposure on the park surface, and (2) the number of 
aircraft operations under various mixes of aircraft types that could 
operate within the total noise budget.
    While complex to develop and administer, the noise budget could 
achieve noise mitigation through directly addressing the issue of noise 
impact but would not address the impacts other than noise. Once the 
``budget'' is established based on target noise levels in various areas 
of the park, air tour operators would have substantial flexibility to 
adjust their business operations without exceeding those levels. The 
noise budget could act as a practical limit on the amount of aviation 
activity, but would not impose limits on the number of operations. A 
noise budget would also represent an incentive for operators to acquire 
relatively quiet aircraft to avoid a penalty on the number of 
operations that could be conducted within each operator's target noise 
level.
    Individual allocations under a noise budget could be established by 
designating maximum noise levels for each operator. This could be done 
by ``grandfathering'' the current noise contribution by each air tour 
operator, or by some other administrative means.

Incentives To Encourage Use of Quiet Aircraft

    Air tour operators could be encouraged to use relatively quiet 
aircraft on park overflights. For example, a flight corridor with a 
good scenic view of the canyon could be limited to aircraft meeting 
certain noise emission standards. An air tour operator could find it 
advantageous to convert its entire fleet to such quiet aircraft to 
incorporate that corridor in its tours. While there is no Federal 
requirement for aircraft to be manufactured to produce less noise than 
Stage 3 standards, some aircraft appropriate for air tour operations 
are quieter than Stage 3. Increased use of such aircraft in air tours 
would achieve noise mitigation through reducing noise levels on the 
surface of the park, although this option does not address issues other 
than noise.

Questions

    The NPS and FAA also solicit comments on several questions related 
to air tour sightseeing operations in and adjacent to units of the 
national park system.

Policy

    1. Should commercial sightseeing flights be prohibited over certain 
national parks? If so, what criteria should be used in determining 
which parks should not have such tours?
    2. Should action pertaining to aircraft overflights in national 
parks be considered only for air tour/sightseeing operations? What 
circumstances would include other categories of overflights?
    3. What factors should be considered by NPS and FAA in evaluating 
recommendations for addressing aircraft overflight issues?

Technical

    1. Is the use of quiet technology aircraft a viable alternative for 
reducing noise from commercial air tour/sightseeing operations in 
national parks?
    2. Should all commercial air tour/sightseeing operations be 
conducted under air carrier rules of FAR part 135 and/or 121?
    3. Should air carrier operators be required to have special 
operations specifications for conducting sightseeing flights?
    4. Should there be special airspace rules for identified units of 
the national park system?
    5. Should the measures developed for Grand Canyon and Hawaii become 
models for more general use at parks with actual or potential 
overflight impacts?

Request for Comments

    The FAA and NPS solicit comments and information from all segments 
of the public interested in aviation and national parks and their 
relationship. The primary focus of this advance notice is commercial 
air sightseeing tours, rather than military or general aviation 
operations. It is anticipated that any regulations eventually developed 
would be general in nature and applicable to the entire national park 
system. It is not the intent of the NPS or FAA to develop regulations 
specific to any one park at this time. However, examples of aviation 
activities observed in one park may be used to support an opinion on 
overall aviation management issues.
    All comments received by FAA and NPS at the addresses and by the 
dates listed above will be reviewed and utilized in any development of 
proposed regulations. Comments received pursuant to this Advance Notice 
of Proposed Rulemaking will be analyzed and discussed in the preamble 
to the Proposed Rule. Any proposed rulemaking will also be made 
available for public review and comment.

Regulatory Process Matters

Economic Impact

    The FAA and NPS are unable to determine at this point the likely 
costs of imposing regulations affecting overflights of national parks 
or the annual effect on the economy. Following a review of the comments 
submitted to this ANPRM, the FAA and NPS will determine what regulatory 
requirements will be proposed, if any, and will review the potential 
costs and benefits, as required by Executive Order 12866.

Significance

    This anticipated rulemaking is not a ``significant regulatory 
action'' as defined in Executive Order 12866. The FAA has determined 
that the ANPRM is not significant under the Regulatory Policies and 
Procedures of the Department of Transportation (44 FR 11034, February 
2, 1979).

Other Regulatory Matters

    At this preliminary stage it is not yet possible to determine 
whether there will be a significant economic impact on a number of 
small entities or what the paperwork burden might be. These regulatory 
matters will be addressed at the time of publication of any NPRM on 
this subject.

List of Subjects

36 CFR Parts 1 through 7

    Grand Canyon National Park, Haleakala National Park, Hawaii 
Volcanoes National Park.

14 CFR Parts 91 and 135

    Aircraft, Airmen, Airports, Air taxis, Air traffic control, 
Aviation safety, Noise control.

    Issued in Washington, DC on March 11, 1994.
Barry L. Valentine,
Assistant Administrator for Policy, Planning, & International Aviation.

George T. Frampton, Jr.,
Assistant Secretary of Interior, Fish and Wildlife and Parks.
[FR Doc. 94-6216 Filed 3-14-94; 12:28 pm]
BILLING CODE 4910-13-M