March 28, 2022

Ms. Rhonda Loh, Superintendent
Hawaii Volcanoes National Park
P.O. Box 52
Hawaii National Park, HI 96718

Subject: Potential Air Tour Management Plan (ATMP) Alternatives for Hawaii Volcanoes National Park

Dear Superintendent Loh:

I am writing on behalf of over 2,100 members of the Coalition to Protect America’s National Parks (Coalition), who collectively represent more than 40,000 years of national park management experience. The Coalition studies, educates, speaks, and acts for the preservation of America’s National Park System. Among our members are former National Park Service (NPS) directors, regional directors, superintendents, resource specialists, rangers, maintenance and administrative staff, and a full array of other former employees, volunteers, and supporters.

We offer the following comments for your consideration regarding Potential Alternatives for the Air Tour Management Plan (ATMP) for Hawaii Volcanoes National Park (HAVO), as described in the Newsletter at:


1. First and foremost, we greatly appreciate that HAVO is conducting a proper planning process in accordance with Council of Environmental Quality (CEQ) National Environmental Policy Act (NEPA) implementing regulations at 40 CFR Parts 1500 – 1508 and the NPS NEPA Handbook 2015: In announcing your plans to prepare an environmental assessment (EA) of potential impacts of air tours at the park, you have invited public comment on potential alternatives; and you have identified a range of alternatives including at least one that would significantly reduce the level of impacts caused by the current level of air tours. Presumably, the EA will disclose, evaluate, and compare the various environmental impacts of those alternatives in order to provide the basis for a reasoned decision about the appropriate level of air tours, if any, at HAVO.

In essence, your approach to conducting this ATMP planning process is consistent with applicable CEQ and NPS guidance and makes good sense to us. We applaud you and the planning team for doing the right thing and following the applicable process requirements that this proposal deserves.

2. The proposed HAVO environmental assessment (EA) demonstrates it is feasible for NPS to consider a range of air tour management alternatives and disclose and evaluate their potential impacts while conducting a legitimate level of NEPA review of those alternatives: This begs the question – Why did NPS not do the same thing at all the other parks that have already issued proposed ATMPs? As a practical matter, all 23 proposed ATMPs are being prepared under the same National Parks Air Tour Management Act requirements and the same court order; so what is the NPS rationale for complying with basic NEPA requirements in only a few cases (e.g., HAVO and HALE) but not in many others?

In stark contrast to this EA, all other NPS proposed ATMPs issued to date have inexplicably failed to consider a range of alternatives, including some that would reduce the level of impacts caused by the current level of air tours. Those ATMPs proposed the current level of air tours as the only management option being considered (which is, in effect, the No Action Alternative). In addition, all of the previously issued proposed ATMPs failed to disclose or evaluate potential environmental impacts of the respective proposed actions.

We ask NPS to explain its basis for deciding to prepare EAs for only a few parks while not considering any alternatives to the proposed action and without disclosing the impacts of the proposed action for many other parks where the agencies have been ordered to prepare ATMPs.

3. The newsletter makes no mention of the NPS Organic Act (54 USC §100101) and offers no explanation as to the Act’s relevance to the proposed action: “The most important statutory directive for the National Park Service is provided by interrelated provisions of the NPS Organic Act of 1916 and the NPS General Authorities Act of 1970, including amendments to the latter law enacted in 1978.” See NPS Management Policies 2006 Section 1.4.1. As further stated in Management Policies Section 1.4.3:

The fundamental purpose of the national park system, established by the Organic Act and reaffirmed by the General Authorities Act, as amended, begins with a mandate to conserve park resources and values. This mandate is independent of the separate prohibition on impairment and applies all the time with respect to all park resources and values, even when there is no risk that any park resources or values may be impaired… Congress, recognizing that the enjoyment by future generations of the national parks can be ensured only if the superb quality of park resources and values is left unimpaired, has provided that when there is a conflict between conserving resources and values and providing for enjoyment of them, conservation is to be predominant. This is how courts have consistently interpreted the Organic Act. (Emphasis added)

Given that the EA is 100% about evaluating potential impacts of commercial air tours on natural and cultural resources and visitor experience opportunities within a unit of the National Park System, we fully expected that the NPS conservation mandate, derived from the Organic Act of 1916, would serve as a key basis for the agencies to evaluate impacts to national park resources and values and determine an appropriate level of air tours, if any. To be clear, Chapter 1 of the EA should include a section summarizing applicable laws, including the NPS Organic Act, relevant to the proposed action.

4. The newsletter fails to identify management objectives related to the development of the ATMP other than compliance with the National Parks Air Tour Management Act of 2000. It also fails to mention the park’s 2016 General Management Plan (GMP), which specified general objectives regarding the management of air tours at HAVO: The 2016 GMP identified a number of management objectives related to commercial air tours. See “Soundscapes and the Acoustic Environment” on p. 47 at:

The GMP discussion of ATMPs includes the following information:

• The NPS, as a cooperator with the FAA, will complete an ATMP/ EIS that will develop measures to limit or prevent any significant impacts that may be caused by commercial air tour operations upon the natural and cultural resources or visitor experiences at the park. This plan will be consistent with the guiding principle of reducing noise/human sound in sensitive areas.
• To improve soundscapes and the acoustic environment, the park will expand active management practices to include: (1) implementing best management practices to limit the duration of artificial noise, (2) maximize human-caused noise free periods, (3) create more opportunities for visitors to experience natural soundscapes, and (4) implement partial closures of air space in sensitive areas. In addition, park operations and projects will be implemented using best management practices to minimize noise impacts.
• The park will strive to improve soundscapes and the acoustic environment by reducing artificial noise within wilderness; in and near critical habitat for threatened and endangered species; in traditional cultural areas such as volcano summits, active lava, or active volcanic features; and in high visitor use areas.
• The GMP also recommends the implementation of a soundscape monitoring program and will consider developing a soundscape management plan, if additional guidance is needed.
(Emphasis added)

Consistent with the above information from the 2016 GMP, we request that the forthcoming EA/plan include the following:

• Adoption of the park GMP’s objectives regarding commercial air tour management.
• Practical, measurable resource protection objectives, along the lines of desired future conditions (DFCs), which when combined with systematic monitoring can be used as the basis for future evaluation of the effectiveness of the plan in accomplishing its resource protection goals.
• A description of the soundscape monitoring program referenced in the GMP.
• An explanation why NPS is not preparing an EIS as indicated in the 2016 GMP.

5. Consistent with Management Policies Section 1.5, the EA should include an “appropriate use analysis” for the proposed action: The National Parks Air Tour Management Act of 2000 (49 USC 40128) does not mandate that commercial air tours are to occur over units of the National Park System. In fact, section (b)(3)(A) of the Act provides that the agencies “may prohibit commercial air tour operations over a national park in whole or in part.” In other words, under the Act air tours are essentially a discretionary activity subject to agency approval. To our knowledge, NPS has never formally considered or determined whether commercial air tours are an appropriate use of (or over) Hawaii Volcanoes National Park. We therefore request that the EA include an appropriate use analysis as described in Management Policies Section 1.5.

6. The EA should also include an “impairment determination” for the proposed action, as described in Management Policies Section 1.4.7, which states, in part: “Before approving a proposed action that could lead to an impairment of park resources and values, an NPS decision-maker must consider the impacts of the proposed action and determine, in writing, that the activity will not lead to an impairment of park resources and values. If there would be an impairment, the action must not be approved.”

Furthermore, “[t]he impact threshold at which impairment occurs is not always readily apparent. Therefore, the Service will apply a standard that offers greater assurance that impairment will not occur. The Service will do this by avoiding impacts that it determines to be unacceptable. These are impacts that fall short of impairment, but are still not acceptable within a particular park’s environment.” Management Policies (Emphasis added)

7. The EA should identify its preparers as well as the respective roles of the NPS and the FAA in the NEPA process: The newsletter solicits public comments that can be submitted electronically, presumably to NPS, via the park’s PEPC website; or in writing (i.e., hard copy), presumably to the U.S. Department of Transportation (USDOT), at the Volpe Center. As a result, it is confusing which agency is actually coordinating preparation of the EA and serves as the “lead agency” as described in 40 CFR §1501.7; and which agency serves as the “cooperating agency” as described in 40 CFR §1501.8.

This is a concern primarily if NPS plays a passive “reviewer only” role as a cooperating agency during the preparation of the pending EA, as it typically does whenever it serves as a cooperating agency. Despite NPS’s tendency to be passively involved, the NEPA implementing regulations provide for a cooperating agency to play a more active role in the planning process and we strongly encourage NPS to do so in this process. For example, 40 CFR 1501.8(b)(3) provides that each cooperating agency “shall… [o]n request of the lead agency, assume responsibility for developing information and preparing environmental analyses, including portions of the environmental impact statement or environmental assessment concerning which the cooperating agency has special expertise.” (Emphasis added)

The NPS Natural Sounds Program clearly has special expertise with regard to measuring and assessing the impacts of air tour noise on park resources and values, including impacts to wildlife, wilderness, and visitor experience. As a result, we would expect the NPS, not the FAA or the Volpe Center, to prepare the analyses of such impacts. Since the primary purpose of the EA is to assess potential impacts of air tours on national park resources and values at HAVO, it is imperative that experienced NPS subject matter experts and NEPA practitioners, who regularly evaluate potential resource impacts through the lens of the NPS conservation mandate, are active participants in preparing the various impact analyses for this proposal.


1. Purpose and Need (p. 3): The Purpose and Need, as written, makes sense to us. The Need statement, in particular, is very well written and should serve as a model Need statement for all other park ATMPs.

2. Resources for Consideration in the EA (p. 3): The proposed list of impact topics appears complete to us. The impact analysis for each topic should include a discussion of available data, such as ambient sound surveys, as well as a review of relevant scientific literature related to the impacts of aircraft noise on specific resources. While this seems like we are stating the obvious, since NONE of the other proposed ATMPs released thus far contained any such information, we feel we need to say it here.

3. Reference materials to consider when preparing the respective impact analyses include the following:

• Effects of Aircraft Overflights on the National Park System. Report to Congress 1995:
• An assessment of noise audibility and sound levels in U.S. National Parks:
• Protecting National Park Soundscapes: National Academy of Engineering 2013:
• Effects of Noise on Wildlife:
• A Synthesis of Two Decades of Research on the Effects of Noise on Wildlife:
• Conserving the wildlife therein – protecting park fauna from anthropogenic noise:
• A review of the effects of aircraft noise on wildlife and humans 2003:
• Effects of Noise on Wilderness:
• Noise pollution is pervasive in U.S. protected areas:
• Effects of Noise on Visitors:
• Effects of Noise on Cultural-Historic Resources:
• HAVO Baseline Ambient Sound Levels 2003:
• HAVO Acoustical Monitoring Report 2013:

While the above list is by no means complete, all of the materials listed above are available via links found on the NPS Natural Sounds Program website at: However, since NONE of this reference material was mentioned in ANY of the proposed park ATMPs issued to date, we feel it is necessary to call this information to your attention now.

4. Alternative 1 – No Action (p. 9): Alternative 1 represents a continuation of what is currently flown and/or allowed under existing law including each company’s Interim Operating Authority (IOA) as granted by the FAA (70 Federal Register 36456 (June 23, 2005). As stated on p. 9, “[t]he no action alternative provides a basis for comparison but is not a selectable alternative because it does not meet the purpose and need for the ATMP and is not in compliance with the Act.” (Emphasis added)

The newsletter also states that the average number of air tour numbers conducted from 2017 to 2019 is 11,376. However, as described under the no action alternative, operators could fly up to the IOA limit of 26,664 air tours per year. One would reasonably expect that the severity of impacts could be quite different between 11,376 flights per year vs. 26,664 allowable under IOAs. As a result, it is unclear from the newsletter what level of air tours (i.e., how many per year) NPS would consider as the baseline level of use for the impact analysis; or if NPS would evaluate the full range of impacts for both the lower and the higher number of possible flights per year.

It would be unreasonable for NPS to evaluate alternative 1 based on the maximum hypothetical number of flights of 26,664, since that number has not been occurring and there is no data documenting the actual impacts of such a high number of flights. On the other hand, there should be data documenting the actual impacts of 11,376 flights per year, which would provide a solid basis of comparison with proposed alternatives 2-4.

We strongly recommend that NPS use 11,376 flights per year (not 26,664) as the baseline for its analysis of impacts for Alternative 1.

5. Range of action alternatives (pp. 13-25): Alternatives 2-4 appear to provide an adequate range of alternatives as required by NEPA. That said, alternatives 3 and 4 are substantially similar, with subtle differences and likely similar overall impacts. For example, both 3 and 4 would allow up to 11,376 air tour flights annually (or as stated in the newsletter “above 1 and below 11,376”), which is essentially the current number of air tours based on the average in 2017-2019. We suggest that the Annual/Daily Number of Flights allowed under alternative 3 be revised to “above 1 and below 5,688” (i.e., half of the current level). This would ensure differentiation in the respective levels of potential impacts caused by alternatives 3 and 4 and provide a more diverse range of alternatives for the agencies and public to consider. See Comment # 7 below.

6. Minimum altitudes proposed for alternatives 3 and 4 (p. 24): Both alternatives would require air tours to fly at a “Minimum 1,500 ft. AGL; minimum 2,000 ft. AGL over wilderness areas and sensitive sites.” We question whether these altitudes are sufficient to minimize noise impacts over national parks and wilderness, and ask that you explain/justify the basis for the selected altitudes in the EA. For example, what guideline(s) or studies can you point to that would support the selected minimum altitude(s)?

We recommend that you consider the following guidance indicating that minimum altitude for air tours, in general, at HAVO in all locations should be at least 2,000 feet AGL (not 1,500 feet as proposed):

• FAA Advisory Circular AC No: 91-36D identifies National Parks, National Wildlife Refuges, Waterfowl Production Areas and Wilderness Areas as “noise sensitive areas”; and recommends that “pilots operating noise producing aircraft (fixed-wing, rotary-wing and hot air balloons) over noise sensitive areas fly not less than 2,000 feet above ground level (AGL), weather permitting.” (Emphasis added) See:$FILE/AC91-36d.pdf
• NPS has adopted AC No. 91-36D’s recommendation on its “mitigating the impacts of aircraft” webpage, which states: “All aircraft are requested to maintain a minimum altitude of 2,000 feet above the surface of lands and waters administered by the NPS, UFWS, or USFS Wilderness areas.” See:,UFWS%2C%20or%20USFS%20Wilderness%20areas.
• Numerous other federal land and marine sanctuary management agencies have similarly adopted 2,000 feet AGL as the recommended minimum altitude for aircraft flying over federally protected areas.
• NPS has presented no justification for proposing to deviate significantly from the longstanding minimum altitude standard of 2,000 feet AGL.
• Lastly, we are not aware of other studies or guidance proposing a specific minimum altitude over wilderness. We therefore support FAA AC No: 91-36D’s recommendation that aircraft fly at least 2,000 feet AGL over wilderness.

7. Annual/Daily Number of Flights (p. 24): Both alternatives 3 and 4 would allow “above 1 and below 11,376 flights per year, dependent on modeling.” We note with concern that 11,376 air tour flights annually is the average number of flights that occurred at HAVO in 2017-2019. In other words, under both alternatives there would/could be NO MEANINGFUL REDUCTION IN THE NUMBER OF AIR TOURS COMPARED TO THE CURRENT AVERAGE. In addition, both alternatives are extremely vague about how such modeling would work; what criteria would be factored into the model(s); and what would be the desired future conditions (DFCs). Presumably, if both alternatives were to use the same modeling criteria and DFCs, both could likely end up with the same or similar number of air tours allowed annually.

In reviewing the Summary of Alternative Elements table on pp. 24-25 of the newsletter, there are a number of subtle differences between alternatives 3 and 4 (e.g., slight differences in the number of routes, time of day, etc.). However, in general the two alternatives are substantially similar in the variety and degree of operating conditions being proposed; and likely would result in similar overall impacts. As a result, the range of alternatives NPS proposes to consider is actually more limited than it would appear by the total number of preliminary alternatives NPS has identified.

In order to ensure a more robust range of alternatives, we strongly encourage NPS to create a greater degree of difference(s) between alternatives 3 and 4, so that their potential impacts are likewise more distinguishable. We recommend that alternative 3 be revised by reducing the number of flights allowed annually to “above 1 and below 5,688 flights per year, dependent on modeling.” (Note: 5,688 is half of 11,376.) This revision would provide a more diverse range of alternatives for the public to consider that would be clearly differentiated by the overall impacts each alternative is likely to cause.

8. Proposed new alternative based on “A Framework to Reduce the Effects of Air Tour Noise on Wilderness”: We recommend that you create an alternative based on “A Framework to Assess the Effects of Commercial Air Tour Noise on Wilderness” proposed by McKenna et al in 2015. See:

The framework proposes that air tour noise impacts over wilderness can be managed and minimized by adjusting the following key factors: area of audibility; percent time audible; and percentage of the year with overflights. The framework can be used to characterize the existing level of air tour impacts as being within one of four “tiers” (or impact levels) described in the study. Areas with the greatest level of air tour noise disturbance are characterized as Tier 4 involving a large spatial area, long time or duration of noise intrusion, and high level of audibility (≥ 35 dB); areas with low disturbance are Tier 1 involving a small spatial area, short time, and low level; and areas with no air tour noise would be Tier 0. Note: Presumably, alternative 2 in the EA would be properly characterized as having Tier 1 (i.e., not Tier 0) level of impacts, since the “no air tours” alternative would still allow air tours to fly at 5,000 feet AGL or higher over the park and would inevitably result in some detectable air tour noise.

In any case, depending upon the current level of impacts (i.e., tier) for wilderness areas at HAVO, to be determined by NPS based on the framework, we suggest an appropriate goal would be to impose operating restrictions at HAVO sufficient to reduce the impacts to wilderness by 1-2 tiers. For example, if current impacts are characterized as Tier 4, the goal should be to reduce them to Tier 2. If current level of impact is Tier 2 or Tier 3, then the goal should be to reduce them to Tier 1.

Note: McKenna et al was prepared with active involvement by NPS Natural Sounds Program staff, so we see no need to further explain the “framework” here.

9. Last but not least, the EA should identify the NPS “preferred alternative” as well as the “environmentally preferable alternative” as described in the NPS NEPA Handbook 2015, Section 4.3:

As described in handbook section 4.3(C), “A preferred alternative is the alternative that ‘would best accomplish the purpose and need of the proposed action while fulfilling [the NPS] statutory mission and responsibilities, giving consideration to economic, environmental, technical, and other factors’ (46.420(d)). It is standard NPS practice to identify the preferred alternative in EAs[.]”

As described in handbook section 4.3 (D), “The environmentally preferable alternative is the alternative developed and analyzed during the NEPA process ‘that causes the least damage to the biological and physical environment and best protects, preserves, and enhances historical, cultural, and natural resources’ (46.30). An environmentally preferable alternative must be identified in a ROD and may be identified in EAs, FONSIs, and draft and final EISs (1505.2(b); 46.450).”

The value of NPS identifying both the preferred alternative and the environmentally preferable alternative in this EA is that it would add much needed transparency to what has been a rather murky and not always public process for the past 20 years. While we appreciate that the agencies are now moving forward with the ATMP planning process at HAVO, the fact remains that stakeholders had to file litigation in order to force NPS and the FAA to comply with the provisions of the National Parks Air Tour Management Act of 2000 after many years of ineffective progress by the agencies. Improving transparency in the planning process would be a helpful step toward restoring public confidence that NPS is fully committed to its conservation mandate such that “when there is a conflict between conserving resources and values and providing for enjoyment of them, conservation is to be predominant.”

In closing, we appreciate the opportunity to comment on this important issue.


Michael Murray signature



sMichael B. Murray, Chair
Coalition to Protect America’s National Parks
2 Massachusetts Ave NE, Unit 77436
Washington, DC 20013

Cindy Orlando, Acting Regional Director, Regions 9, 10 and 12, National Park Service
Karen Trevino, Chief, Natural Sounds and Night Skies Division, National Park Service
Ray Sauvajot, Associate Director for Natural Resource Stewardship and Science, NPS