A bill to require the Secretary of the Interior to conduct a study to determine the appropriate minimum altitude for aircraft flying over national park system units.
PL 100-91 (H.R.921), enacted 08/18/1987

101 STAT. 674 
PUBLIC LAW 100-91—AUG. 18, 1987 
Public Law 100-91 
100th Congress 
An Act 
Aug. 18, 1987 
[H.R. 921] 
16 u s e la-1 
note. 
Safety. 
Pollution. 
Alaska. 
To require the Secretary of the Interior to conduct a study to determine the 
appropriate minimum altitude for aircraft flying over national park system units. 
Be it enacted by the Senate and House of Representatives of the 
United States of America in Congress assembled, 
SECTION 1. STUDY OF PARK OVERFLIGHTS. 
(a) STUDY BY PARK SERVICE.—The Secretary of the Interior 
(hereinafter referred to as the "Secretary"), acting through the 
Director of the National Park Service, shall conduct a study to 
determine the proper minimum altitude which should be main-
tained by aircraft when flying over units of the National Park 
System. The Secretary of Transportation, acting through the 
Administrator of the Federal Aviation Administration (hereinafter 
referred to as the "Administrator"), shall provide technical assist-
ance to the Secretary in carrying out the study. 
(b) GENERAL REQUIREMENTS OF STUDY.—The study shall identify 
any problems associated with overflight by aircraft of units of the 
National Park System and shall provide information regarding the 
types of overflight which may be impacting on park unit resources. 
The study shall distinguish between the impacts caused by sightsee-
ing aircraft, military aircraft, commercial aviation, general avia-
tion, and other forms of aircraft which affect such units. The study 
shall identify those park system units, and portions thereof, in 
which the most serious adverse impacts from aircraft overflights 
exist. 
(c) SPECIFIC REQUIREMENTS.—The study under this section shall 
include research at the following units of the National Park System: 
Cumberland Island National Seashore, Yosemite National Park, 
Hawaii Volcanoes National Park, Haleakala National Park, Glacier 
National Park, and Mount Rushmore National Memorial, and at no 
less than four additional units of the National Park System, exclud-
ing all National Park System units in the State of Alaska. The 
research at each such unit shall provide information and an evalua-
tion regarding each of the following: 
(1) the impacts of aircraft noise on the safety of the park 
system users, including hikers, rock-climbers, and boaters; 
(2) the impairment of visitor enjoyment associated with 
flights over such units of the National Park System; 
(3) other injurious effects of overflights on the natural, histori-
cal, and cultural resources for which such units were estab-
lished; and 
(4) the values associated with aircraft flights over such units 
of the National Park System in terms of visitor enjoyment, the 
protection of persons or property, search and rescue operations 
and firefighting. 
Such research shall evaluate the impact of overflights by both fixed-
wing aircraft and helicopters. The research shall include an evalua-
tion of the differences in noise levels within such units of the 
PUBLIC LAW 100-91—AUG. 18, 1987 
101 STAT. 675 
National Park System which are associated with flight by commonly 
used aircraft at different altitudes. The research shall apply only to 
overflights and shall not apply to landing fields within, or adjacent 
to, such units. 
(d) REPORT TO CONGRESS.—The Secretary shall submit a report to 
the Congress within 3 years after the enactment of this Act contain-
ing the results of the study carried out under this section. Such 
report shall also contain recommendations for legislative and regu-
latory action which could be taken regarding the information gath-
ered pursuant to paragraphs (1) through (4) of subsection (c). Before 
submission to the Congress, the Secretary shall provide a draft of 
the report and recommendations to the Administrator for review. 
The Administrator shall review such report and recommendations 
and notify the Secretary of any adverse effects which the im-
plementation of such recommendations would have on the safety of 
aircraft operations. The Administrator shall consult with the Sec-
retary to resolve issues relating to such adverse effects. The final 
report shall include a finding by the Administrator that im-
plementation of the recommendations of the Secretary will not have 
adverse effects on the safety of aircraft operations, or if the 
Administrator is unable to make such finding, a statement by the 
Administrator of the reasons he believes the Secretary's rec-
ommendations will have an adverse effect on the safety of aircraft 
operations. 
(e) FAA REVIEW OF RULES.—The Administrator shall review cur-
rent rules and regulations pertaining to flights of aircraft over units 
of the National Park System at which research is conducted under 
subsection (c) and over any other such units at which such a review 
is determined necessary by the Administrator or is requested by the 
Secretary. In the review under this subsection, the Administrator 
shall determine whether changes are needed in such rules and 
regulations on the basis of aviation safety. Not later than 180 days 
after the identification of the units of the National Park System for 
which research is to be conducted under subsection (c), the Adminis-
trator shall submit a report to Congress containing the results of the 
review along with recommendations for legislative and regulatory 
action which are needed to implement any such changes. 
(f) AUTHORIZATION.—There are authorized to be appropriated such 
sums as may be necessary to carry out the studies and review under 
this section. 
SEC. 2. FLIGHTS OVER YOSEMITE AND HALEAKALA DURING STUDY AND 
REVIEW. 
(a) YosEMiTE NATIONAL PARK.—During the study and review peri-
ods provided in subsection (c), it shall be unlawful for any fixed wing 
aircraft or helicopter flying under visual flight rules to fly at an 
altitude of less than 2,000 feet over the surface of Yosemite National 
Park. For purposes of this subsection, the term "surface" refers to 
the highest terrain within the park which is within 2,000 feet 
laterally of the route of flight and with respect to Yosemite Valley 
such term refers to the upper-most rim of the valley. 
(b) HALEAKALA NATIONAL PARK.—During the study and review 
periods provided in subsection (c), it shall be unlawful for any fixed 
wing aircraft or helicopter flying under visual flight rules to fly at 
an altitude below 9,500 feet above mean sea level over the surface of 
any of the following areas in Haleakala National Park: Haleakala 
Safety. 
Reports. 
Appropriation 
authorization. 
16 u s e la-1 
note. 
91-194 O - 90 - 23 : QL.3 Part 1 
101 STAT. 676 
PUBLIC LAW 100-91—AUG. 18, 1987 
Public 
information. 
49 u s e app. 
1348. 
Safety. 
Pollution 
16 u s e la 
note. 
-1 
Indians. 
Arizona. 
*lii 
Crater, Crater Cabins, the Scientific Research Reserve, Halemauu 
Trail, Kaupo Gap Trail, or any designated tourist viewpoint. 
(c) STUDY AND REVIEW PERIODS.—For purposes of subsections (a) 
and (b), the study period shall be the period of the time after the 
date of enactment of this Act and prior to the submission of the 
report under section 1. The review period shall comprise a 2-year 
period for Congressional review after the submission of the report to 
Congress. 
(d) EXCEPTIONS.—The prohibitions contained in subsections (a) and 
(b) shall not apply to any of the following: 
(1) emergency situations involving the protection of persons 
or property, including aircraft; 
(2) search and rescue operations; 
(3) flights for purposes of firefighting or for required adminis-
trative purposes; and 
(4) compliance with instructions of an air traffic controller. 
(e) ENFORCEMENT.—For purposes of enforcement, the prohibitions 
contained in subsections (a) and (b) shall be treated as requirements 
established pursuant to section 307 of the Federal Aviation Act of 
1958. To provide information to pilots regarding the restrictions 
established under this Act, the Administrator shall provide public 
notice of such restrictions in appropriate Federal Aviation Adminis-
tration publications as soon as practicable after the enactment of 
this Act. 
SEC. 3. GRAND CANYON NATIONAL PARK. 
(a) Noise associated with aircraft overflights at the Grand Canyon 
National Park is causing a significant adverse effect on the natural 
quiet and experience of the park and current aircraft operations at 
the Grand Canyon National Park have raised serious concerns 
regarding public safety, including concerns regarding the safety of 
park users. 
(b) RECOMMENDATIONS.— 
(1) SUBMISSION.—Within 30 days after the enactment of this 
Act, the Secretary shall submit to the Administrator rec-
ommendations regarding actions necessary for the protection of 
resources in the Grand Canyon from adverse impacts associated 
with aircraft overflights. The recommendations shall provide 
for substantial restoration of the natural quiet and experience 
of the park and protection of public health and safety from 
adverse effects associated with aircraft overflight. Except as 
provided in subsection (c), the recommendations shall contain 
provisions prohibiting the flight of aircraft below the rim of the 
Canyon, and shall designate flight free zones. Such zones shall 
be flight free except for purposes of administration and for 
I 
emergency operations, including those required 
for 
the 
{ 
transportation of persons and supplies to and from Supai Vil-
lage and the lands of the Havasupai Indian Tribe of Arizona. 
i 
The Administrator, after consultation with the Secretary, shall 
define the rim of the Canyon in a manner consistent with the 
purposes of this paragraph. 
(2) IMPLEMENTATION.—Not later than 90 days after receipt of 
the recommendations under paragraph (1) and after notice and 
i 
opportunity for hearing, the Administrator shall prepare and 
J 
issue a final plan for the management of air traffic in the air 
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space above the Grand Canyon. The plan shall, by appropriate 
£
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regulation, implement the recommendations of the Secretary 
PUBLIC LAW 100-91—AUG. 18, 1987 
101 STAT. 677 
Regulations. 
49 use app. 
1301 note. 
without change unless the Administrator determines that im-
plementing the recommendations would adversely affect avia-
tion safety. If the Administrator determines that implementing 
the recommendations would adversely affect aviation safety, he 
shall, not later than 60 days after making such determination, 
in consultation with the Secretary and after notice and oppor-
tunity for hearing, review the recommendations consistent with 
the requirements of paragraph (1) to eliminate the adverse 
effects on aviation safety and issue regulations implementing 
the revised recommendations in the plan. In addition to the 
Administrator's authority to implement such regulations under 
the Federal Aviation Act of 1958, the Secretary may enforce the 
appropriate requirements of the plsm under such rules and 
regulations applicable to the units of the National Park System 
as he deems appropriate. 
(3) REPORT.—Within 2 years after the effective date of the 
plan required by subsection 03)(2), the Secretary sh£ill submit 
to the Congress a report discussing— 
(A) whether the plan has succeeded in substantiedly 
restoring the natural quiet in the park; and 
(B) such other matters, including possible revisions in the 
plan, as may be of interest. 
The report shall include comments by the Administrator regarding 
the effect of the plan's implementation on aircraft safety. 
(c) HELICOPTER FUGHTS OF RIVER RUNNERS.—Subsection (b) shall 
not prohibit the flight of helicopters— 
(1) which fly a direct route between a point on the north rim 
outside of the Grand Cginyon National Park and locations on the 
Hualapai Indian Reservation (as designated by the Tribe); and 
(2) whose sole purpose is transporting individuals to or from 
boat trips on the Colorado River and any guide of such a trip. 
SEC. 4. BOUNDARY WATERS CANOE AREA WILDERNESS. 
The Administrator shall conduct surveillance of aircraft flights 
over the Boundary Waters Canoe Area Wilderness as authorized by 
the Act of October 21, 1978 (92 Stat. 1649-1659) for a period of not 
less than 180 days beginning within 60 days of enactment of this 
Act. In addition to any actions the Administrator may take as a 
result of such surveillance, he shall provide a report to the Com-
mittee on Interior and Insular Affairs and the Committee on Public 
Works and Transportation of the United States House of Represent-
atives and to the Committee on Energy and Natural Resources and 
the Committee on Commerce, Science, and Transportation of the 
United States Senate. Such report is to be submitted within 30 days 
of completion of the surveillance activities. Such report shall include 
but not necessarily be limited to information on the tjrpe and 
frequency of aircraft using the airspace over the Boundary Waters 
Canoe Area Wilderness. 
SEC. 5. ASSESSMENT OF NATIONAL FOREST SYSTEM WILDERNESS 
16 USC la-1 
OVERFLIGHTS. 
note. 
(a) ASSESSMENT BY FOREST SERVICE.—The Chief of the Forest 
Service (hereinafter referred to as the "Chief) shall conduct an 
assessment to determine what, if any, adverse impacts to wilderness 
resources are gissociated with overflights of National Forest System 
wilderness areas. The Administrator of the Federal Aviation 
Administration shall provide technical assistance to the Chief in 
Indians. 
16 USC la-1 
note. 
Reports. 
101 STAT. 678 
PUBLIC LAW 100-91—AUG. 18, 1987 
Alaska. 
Appropriation 
authorization. 
16 u s e la-1 
note. 
carrying out the assessment. Such assessment shall apply only to 
overflight of wilderness areas and shall not apply to aircraft flights 
or landings adjacent to National Forest System wilderness units. 
The assessment shall not apply to any National Forest System 
wilderness units in the State of Alaska. 
(b) REPORT TO CONGRESS.—The Chief shall submit a report to 
Congress within 2 years after enactment of this Act containing the 
results of the assessments carried out under this section. 
(c) AUTHORIZATION.—Effective October 1, 1987, there are au-
thorized to be appropriated such sums as may be necessary to carry 
out the assessment under this section. 
SEC. 6. CONSULTATION WITH FEDERAL AGENCIES. 
In conducting the study and the assessment required by this Act, 
the Secretary of the Interior and the Chief of the Forest Service 
shall consult with other Federal agencies that are engaged in an 
analysis of the impacts of aircraft overflights over federally-owned 
land. 
Approved August 18, 1987. 
_5-;. 
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LEGISLATIVE HISTORY—H.R. 921: 
HOUSE REPORTS: No. 100-69, Pt. 1 (Coram, on Interior and Insular Affairs). 
SENATE REPORTS: No. 100-97 (Coram, on Energy and Natural Resources) and No. 
100-125 (Coram, on Comraerce, Science, and Transportation). 
CONGRESSIONAL RECORD, Vol. 133 (1987): 
May 4, considered and passed House. 
' 
July 28, considered and passed Senate, araended. 
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Aug. 3, House concurred in Senate amendraent. 
WEEKLY COMPILATION OF PRESIDENTIAL DOCUMENTS, Vol. 23 (1987): 
Aug. 18, Presidential statement. 
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