October 3, 2022

Ms. Michelle Wheatley, Superintendent
Mount Rushmore National Memorial
13000 Highway 244
Building 31, Suite 1
Keystone, SD 57751

Subject: Potential Air Tour Management Plan (ATMP) Alternatives for Mount Rushmore National Memorial

Dear Superintendent Wheatley:

I am writing on behalf of over 2,200 members of the Coalition to Protect America’s National Parks (Coalition), who collectively represent more than 45,000 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 Mount Rushmore National Memorial (MORU), as described in the Newsletter at: https://parkplanning.nps.gov/document.cfm?parkID=152&projectID=97377&documentID=123303


  1. First, we appreciate that MORU plans to prepare an environmental assessment (EA) 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 2015We have been deeply concerned about the many proposed ATMPs for other parks that NPS issued previously without considering a reasonable range of alternatives and without preparing any sort of NEPA compliance for public review. We applaud you and the planning team for following the applicable process requirements that this proposal deserves.

However, the fact that you are preparing an EA while most parks have not begs the question – why did NPS not prepare an EA for many of the other parks that have already issued “proposed ATMPs”? As a practical matter, all 24 proposed ATMPs are being prepared under the same court order; but NPS is preparing an EA in only a very limited number of cases. We therefore ask NPS to explain in the forthcoming EA its basis for deciding to prepare an EA for MORU while not doing so for many other parks where the NPS and the FAA have also been ordered to prepare ATMPs.

  1. The planning newsletter makes no mention of the NPS Organic Act (54 USC §100101) and offers no explanation as tothe Act’s relevance to the proposed actionWhile the National Parks Air Tour Management Act of 2000 requires the FAA and NPS to prepare ATMPs for parks where a certain level of commercial air tours have occurred, the NPS Organic Act requires NPS to protect park resources and values, which is, or at least should be, the core purpose of an ATMP. As with all NPS management plans, the NPS “conservation mandate” should drive the ATMP planning process and serve as the basis for evaluating the adequacy of proposed restrictions and related protective measures intended to minimize adverse impacts of air tours over parks.

Regarding the Organic Act, NPS Management Policies 2006 Section 1.4.1 states:“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.” 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 this EA is or should be focused on 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 would expect the NPS conservation mandate to 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. 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.

  1. As described in MORU’s 2015 Foundation Document, the visitor experience at MORU is closely associated with the “natural setting” of the Sculpture. As a result, NPS should make it a high priority to protect the natural setting at established viewing areas from visual and noise intrusions caused by low flying air tour aircraftSee: http://npshistory.com/publications/foundation-documents/moru-fd-2015.pdf

Relevant sections of the Foundation Document include the following:

(p. 6) Fundamental Resources and Values: “Fundamental resources and values help focus planning and management efforts on what is truly significant about the park. One of the most important responsibilities of NPS managers is to ensure the conservation and public enjoyment of those qualities that are essential (fundamental) to achieving the purpose of the park and maintaining its significance. (Emphasis added) If fundamental resources and values are allowed to deteriorate, the park purpose and/or significance could be jeopardized. The following fundamental resources and values have been identified for Mount Rushmore National Memorial:

The Natural Setting. The Black Hills of South Dakota provide a dramatic natural setting for the sculpture at Mount Rushmore National Memorial. The pine forest, landscaping, natural soundscape, and night sky that comprise this setting are important not only for their aesthetic appeal, but also represent a place of great spiritual and cultural significance to the American Indian tribes who have connections to the land.(Emphasis added)

Views of the Sculpture. The views of the sculpture are critical to the experience at Mount Rushmore National Memorial. A variety of viewing opportunities are provided throughout the site, including the unimpeded views at Grand View Terrace, historic views from the sculptor’s studio, and modern views from the Avenue of Flags and points along the highway. Visitors can gain an appreciation of the scale and setting of the sculpture as they move between these viewing opportunities. (Emphasis added)

(p. 16) Threats to the Natural Setting – “Noise from helicopters has impacted visitor experience and wildlife within the park.”

(p. 17) Existing Data – “Soundscape study.” Comment: We know that soundscape data exists for many parks where commercial air tours have been occurring; yet NPS has not provided any such information in any of the other ATMP planning documents to date. We therefore ask that NPS include detailed information from its MORU soundscape study in the upcoming EA. For example, to the extent that the study is relatively recent, it could/should serve as the baseline description of noise levels resulting from the current numbers of air tours that have been occurring, essentially unregulated except for an upper limit on the number of flights, under an Interim Operating Authority (IOA).

The numbers of visitors potentially impacted by air tours should also be considered in the EA. MORU typically receives over 2 million visitors per year; and, as previously described, the quality of their experience is closely associated with the quality of the park’s “natural setting.” MORU is relatively unique among units of the National Park System in that virtually 100% of its visitors are there to see one thing – the iconic Sculpture in its natural setting. The vast majority of those visitors will experience the Sculpture from the unimpeded views at Grand View Terrace, historic views from the sculptor’s studio, and modern views from the Avenue of Flags.

We urge NPS to make it a high priority to protect this highly treasured visitor experience from visual intrusions and noise impacts caused by air tours flying above or near the established viewing areas. Protective measures (or “Alternative Attributes” as NPS calls them) should include constraints that eliminate visible overflights that could be easily seen by visitors from the viewing areas; and additional measures designed to minimize the intrusion of aircraft noise into the viewing areas. We will recommend modification of some of the proposed Attributes later in this letter.

  1. 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) established procedural requirements for allowing air tours over parks; however, the Act does NOT mandate that commercial air tours are appropriate and must be allowed. 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.” 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) MORU. We therefore request that the EA include an appropriate use analysis as described in Management Policies Section 1.5.
  1. The EA should 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.” (Emphasis added)

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.” See Management Policies (Emphasis added)

  1. The EA should identify its preparers as well as the respective roles of the NPS and the FAA/USDOT in the NEPA process The newsletter solicits public comments that may be submitted electronically to the NPS via the park’s PEPC website; or in writing (i.e., hard copy) 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 NPS often does when it functions as a cooperating agency. In contrast, the CEQ NEPA implementing regulations provide for a cooperating agency to play a much more active role in the planning process and we strongly encourage NPS to do so in this case. 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 park resources and values at MORU, 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. Resources for Consideration in the EA (p. 4) The proposed list of impact topics appears complete to us. We especially appreciate that NPS has distinguished between and will separately analyze impacts to: Noise and compatible land use (acoustic environment and Park soundscape); Visitor experience; Visual effects (visual resources and visual character); and Wilderness. The impact analysis for each topic should include a discussion of available data, such as previous sound surveys, as well as a review of relevant scientific literature related to the impacts of aircraft noise on specific resources. When analyzing impacts to the Visitor Experience in the EA, we encourage NPS to describe the close connection between the quality of the natural setting and the quality of the visitor experience. In essence, protecting the visitor experience at MORU requires minimizing air tour impacts at the primary viewing areas for the Sculpture.
  1. Thus far, no NPS-proposed ATMP has identified any applicable reference materials or data that were considered by NPS during the preparation of the proposed action. We therefore ask NPS to actively consider the following information, as well as other references identified in other sections of our comments, during the preparation of the EA for MORA:

In general, all of the reference materials listed above are available via links found on the NPS Natural Sounds Program website at: https://www.nps.gov/subjects/sound/index.htm Since NPS has NOT referred to any of this information in ANY of the previous proposed ATMPs issued to date, we ask NPS to include it now in the upcoming MORU EA.

In addition, the MORU Baseline Ambient Sound Levels report cited above is obviously quite dated. NPS should consider doing a new survey to more accurately document the noise impacts of the current level of air tours. Ideally NPS would produce an ATMP that results in a measurable reduction in noise impacts in the affected park. However, if  NPS does not have reasonably accurate and current baseline data, then measuring the effectiveness of the plan at reducing ambient sound levels will be not be possible.

  1. Alternatives Considered but Dismissed (pp. 6-7) – This section indicates that “[t]he agencies considered but dismissed alternatives that would allow air tour operations at or above existing numbers… because the NPS determined they would result in unacceptable impacts to the Park’s natural and cultural resources, and visitor enjoyment.” Table 1 (p. 9) identifies the “existing” (or recent annual average) number of flights to be 3,914 from 2017-2019. We agree with the NPS determination and will refer to this information in our comments about Alternative 3 below.
  1. Alternative 1 – No Action/No ATMP (pp. 8-10)As described in the “Objective” section for this alternative,” [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) We agree that Alternative 1 is not selectable for the reasons stated.

However, NPS describes Alternative 1 as allowing the maximum theoretical number of flights (5,608) that could occur under Interim Operating Authorities (IOAs), rather than as the “existing number” of flights (i.e., 3,914 from 2017-2019) identified in Table 1. We have several concerns about NPS’s choice to describe the No Action Alternative as the maximum theoretical number of air tour flights allowable under the IOAs, rather than the much more realistic “existing numbers of flights with current operating parameters” (which the agencies also considered but dismissed). See Comment # 4 above.

While we would expect NPS to have documentation and data regarding impacts of the existing numbers of flights, we question whether the maximum theoretical number of flights (5,608) can serve as a valid “basis for comparison” with the proposed action alternatives. As described in the NPS NEPA Handbook 2015, p. 56:

It is important to note that the no-action alternative is different than the baseline used for predicting changes to the condition of resources. The current state of the resources affected (typically what is described in the affected environment section of a NEPA document) serves as the baseline for predicting changes to the human environment that could occur if any of the alternatives under consideration, including the no-action alternative, are implemented. The current state of the resources affected (typically what is described in the affected environment section of a NEPA document) serves as the baseline for predicting changes to the human environment that could occur if any of the alternatives under consideration, including the no-action alternative, are implemented. (Emphasis added)

For the basis of comparison with the action alternatives, we recommend that NPS consider the “existing number” of flights (3,914) as the baseline in the No Action Alternative, rather than the theoretical maximum (5,608) allowed under the IOAs. First, the agencies have already determined that the “existing number” of flights is not selectable “because the NPS determined they would result in unacceptable impacts to the Park’s natural and cultural resources, and visitor enjoyment.” Whereas that determination already establishes a practical baseline for what would be “unacceptable,” using the maximum theoretical number of flights as the baseline for comparison would only obscure the threshold between “unacceptable” and “acceptable” levels of impacts.

In addition, NPS likely has information and data regarding actual impacts of the existing numbers of flights that would allow for a meaningful analysis and comparison of the baseline with the action alternatives. In contrast, there is likely no such information on hand to document the potential impacts of a much higher theoretical number of flights that could occur under the IOAs (but has not). Using non-existent information as the baseline for comparison obviously makes meaningful comparison and analysis much more difficult. Lastly, we believe such a comparison (to the much higher theoretical number) would only serve to make Alternative 3 appear more acceptable than it really is in terms of the relative severity of its impacts.

We therefore recommend that NPS consider “the existing number of flights with current operating parameters” as the No Action Alternative in the EA. It would provide a much more accurate description of what has actually been happening under a “No ATMP” scenario; and thus allow for more meaningful analysis and comparison(s) between the No Action and the Action Alternatives.

  1. Action Alternatives (pp. 11-22): General CommentIn general, alternatives 2-4 provide a range of alternatives as required by NEPA. Of these, Alternative 2, no air tours, would undoubtedly cause the least amount of impacts; and Alternative 3 (Daily Cap of 25 Air Tours with Additional Modifications) would cause the most severe impacts, based largely on the proposed flight numbers. In contrast, Alternative 4 (Daily Cap of 13 Air Tours with Additional Modifications) would cause a moderate level of impacts.

A concern is that the differentiation between action alternatives 3 and 4 is not as great as it could, or perhaps should, be, to provide for a meaningful comparison of “Alternative Attributes” and associated impacts. As summarized in Table 6, except for the differences in annual and daily flight number limits, Alternatives 3 and 4 are virtually the same on all other Attributes, including ALL of the following: Routes; Minimum Altitudes; Time of Day; Seasonal Restrictions; Day of Week; Quiet Technology (QT) Incentives; Operator Training and Education; Annual Meeting; Restrictions for Particular Events; Adaptive Management; and Amendments.

We have specific concerns about some of the Attributes described for Alternatives 2 and 3. To provide a more meaningful analysis and comparison of potential impacts that may be caused by the respective alternatives (as a result of their Attributes), we recommend that NPS consider varying (between Alternatives 2 and 3) the Attributes that are most likely to contribute to the overall level of impacts. We will provide suggestions for revising those Attributes in our comments about Alternative 4 below.

  1. Alternative 2: No Air Tours in the Planning Area (pp. 11-13) – We strongly endorse Alternative 2 because, as described in the newsletter, it “would provide the greatest protection of the Park’s natural and cultural resources and visitor experience management objectives.” However, we are very concerned with the boilerplate language used in the “Amendment” section on p. 12, which states that “the ATMP may be amended at any time” if either the NPS or the FAA notifies the other agency. This seems to unnecessarily leave the door open for future resumption of commercial air tours at MORU, even if the final ATMP were to eliminate all air tours.

Our experience has been that many NPS decisions to curtail or eliminate controversial recreational and commercial activities in parks, such as commercial air tours, ORV use, hunting, etc., are subject to industry lobbying and political reversal, especially when there is a change in administration. The Amendment provision in Alternative 2 provides no certainty that air tours would, in fact, remain eliminated at MORU if this alternative were selected. We therefore ask NPS to eliminate the “Amendment” provision in this alternative, so that a decision to eliminate air tours at MORU is “final” and cannot be easily reversed without the agencies initiating and completing an entirely new planning process.

  1. Alternative 3: Daily Cap of 25 Air Tours with Additional Modifications (pp. 14-10) – In general, we do not support Alternative 3 as it would cause the most extensive adverse impacts of any of the action alternatives. Our foremost concern about Alternative 3 is that it would allow 3,657 flights annually, which is only 7% fewer than the “existing number” of 3,914 flights that NPS has already “considered but dismissed” because it “would result in unacceptable impacts.” See Comment # 4 above.

It is difficult to believe that a mere 7% reduction in the total number of flights could change the impact level from “unacceptable” to “acceptable.” We do understand that the small reduction in the number of flights proposed for Alternative 3 would be combined with implementation of operating parameters (or proposed “Alternative Attributes”). However, based on the limited information provided in the newsletter, it is unclear to us how and how much the proposed “Attributes” could sufficiently reduce air tour noise to change the impact level from “unacceptable” to “acceptable” for nearly the same number of flights that NPS determined would cause “unacceptable impacts” under “current operating parameters.” We therefore ask NPS to explain in the EA how and to what extent specific Attributes would, in fact, reduce impacts compared to the current situation. This should include whatever information and evidence NPS has to support whatever the purported reduction(s) in noise levels would be if the Attributes are implemented at MORU.

Lastly, we have concerns about some of the Attributes described for Alternative 3, which we believe are not sufficiently protective of the park visitor experience at MORU. However, for the sake of encouraging NPS to analyze a broader range of alternatives and Attributes, we will describe these concerns below in our comments about Alternative 4.

  1. Alternative 4: Daily Cap of 13 Air Tours with Additional Modifications (pp. 20-22) – We strongly support the proposed reductions in the annual and daily caps on the number of air tours that would be implemented under this alternative, which are 1,833/year and 13/day respectively (or about 50% fewer flights than would be allowed under Alternative 3). We believe that the most direct and effective way to reduce cumulative air tour impacts is to reduce the total number of flights allowed; and Alternative 4 would clearly accomplish that.

However, our primary concern about Alternative 4 is that it is exactly the same as Alternative 3 for the vast majority of Alternative Attributes that would be implemented. The primary difference between the two would only be the number of flights allowed. As summarized in Table 6, the common Attributes shared by Alternatives 3 and 4 include: Routes and Altitudes; Time of Day, Day of Week, and Seasonal Restrictions; Quiet Technology (QT) Incentives; Restrictions for Particular Events; Adaptive Management; Operator Training and Education; Annual Meeting; Competitive Bidding; Operators, Initial Allocation of Air Tours, Aircraft Types, and Interim Operating Authority; New Entrant; Monitoring and Enforcement; and Amendment.

Having both alternatives share many of the same Attributes unnecessarily limits the range of protective measures being considered and to be analyzed in the EA. As stated previously, the quality of the visitor experience at MORU is closely connected to and dependent upon the quality of the natural setting, including natural ambient sound levels, surrounding the Sculpture. Rather than assume that ALL the common Attributes are “spot on” as proposed, we recommend that NPS consider different levels of intensity for at least some of them. This would expand the range of Attributes being considered and allow for a more meaningful analysis of impacts and comparison of the effectiveness of not only the respective alternatives, but also the Attributes themselves in the EA. We therefore suggest that the following Attributes be revised and considered under Alternative 4:

  1. Flight Routes – We have two primary concerns about the proposed flight routes for Alternative 4 as shown in Figure 5. First, we ask NPS to explain the basis for deciding that a 2,600-foot setback from the Sculpture (i.e., the Red circle in Figure 5) is sufficient to minimize aircraft noise on the ground within the primary viewing areas on the southeast side of the Sculpture. We do not believe that the 2,600-foot setback from the Sculpture will be sufficient to minimize the noise of numerous flights per day that adversely impact the natural setting within which the majority of park visitors view the Sculpture. Furthermore, we suggest that the hard (i.e., rocky) elevated surface of Mount Rushmore likely reflects aircraft sounds coming from that same southeast side of the Sculpture, which may compound the impacts of nuisance aircraft noise experienced from the viewing area. We therefore recommend that NPS consider a 3,900-foot (i.e., 50% larger) setback under Alternative 4 in order to create greater differentiation in the level of impacts between Alternatives 3 and 4. This would allow a more meaningful analysis of the relative impacts of different setback distances as well as of the effectiveness of the proposed 2,600-foot setback distance.

Conversely, if NPS believes that 2,600-foot is setback is completely adequate to protect the visitor experience at Mount Rushmore, then we ask NPS to provide modeling and/or air contour map analysis to support such a finding. Note: There are a number of references describing the modeling of aircraft noise and development of air contour maps (e.g., https://onlinepubs.trb.org/onlinepubs/acrp/acrp_wod_043.pdf; and https://www.faa.gov/regulations_policies/policy_guidance/noise/basics).

Second, the meandering flight routes shown in Figure 5 would allow virtually every air tour to conduct three “fly-bys” on the same southeast side of the Sculpture, with each fly-by leg being located at a different distance. Having the aircraft meander back and forth 3 times just outside the visitor center complex will undoubtedly increase the nuisance factor of aircraft noise impacting park visitors on the ground. We therefore recommend that NPS consider a “two fly-by” route option in Alternative 4. This, when combined with the 3,900 foot setback described above, would eliminate the closest fly-by portion of the routes shown in Figure 5; and thus significantly reduce the impacts of air tour noise to park visitors on the ground.

  1. Minimum Altitudes – We have several concerns about Alternative 4’s proposed minimum altitudes for helicopters (900 feet AGL) and airplanes (1,300 feet AGL). First, we are particularly concerned about the adequacy of the 900 feet AGL requirement for helicopters. Many of our members have experience working in and around helicopters during the course of their NPS careers (e.g., for wildland firefighting or search and rescue purposes). Our observation is that helicopters typically fly lower and slower and are perceived as being much louder and more annoying to people on the ground than a single-engine airplane flying higher and faster overhead.

Our observation is borne out by multiple references that document that helicopters noise is widely perceived as being louder and more annoying than airplane noise. For example, see: https://executiveflyers.com/why-are-helicopters-so-loud/;https://www.noisequest.psu.edu/sourcesofnoise-helicopternoise.html; and https://vtol.org/files/dmfile/12HelicopterNoiseLeverton2.pdf. According to the Helicopter Association International (HAI), the sound of a helicopter flying at 500 feet is about 87 decibels. At 1,000 feet, the sound drops to 78 decibels, which is still louder than a vacuum cleaner and nearly as loud as a hair dryer (see: https://aerocorner.com/blog/why-are-helicopters-so-loud/).

Can you imagine having your once-in-a-lifetime visit to Mount Rushmore ruined by having to listen to someone next to you on the Avenue of Flags using a vacuum cleaner or a hair dryer? Obviously, that is unlikely to happen; yet, NPS is proposing essentially the same sound level equivalent of that (i.e., the same intensity of noise impact) with 900-foot minimum altitude for helicopters at MORU. We could continue identifying references about the how loud and annoying people perceive low flying helicopters to be. However, our point is that the proposed minimum altitude of 900 feet AGL for air tour helicopters is clearly insufficient to minimize nuisance noise intrusions and prevent visitor disturbance within the primary Sculpture viewing areas at MORU.

Our second concern relates to the fact that significant portions of the proposed air tour routes would fly directly over the Black Elk Wilderness adjacent to the memorial. The proposed minimum altitudes are clearly insufficient to prevent significant noise impacts on wilderness character. We recommend that all air tour aircraft be required to fly at least 2,000 feet AGL over designated wilderness.

Last but not least, the proposed minimum altitudes at MORU are considerably lower than FAA’s own recommendations for minimizing aircraft noise impacts over national parks, wilderness areas, and other “noise sensitive areas.” Specifically, 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: https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/list/AC%2091-36D/$FILE/AC91-36d.pdf. Similarly, NPS has adopted AC No. 91-36D’s recommendation that “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: https://www.nps.gov/articles/mitigating-the-impacts-of-aviation.htm#:~:text=All%20aircraft%20are%20requested%20to,UFWS%2C%20or%20USFS%20Wilderness%20areas.

Given each agency’s recommendations about minimum flight altitudes, the NPS and the FAA have presented no justification for proposing to deviate so significantly from their respective longstanding minimum altitude standard of 2,000 feet AGL over national parks and wilderness areas. To address these concerns and provide a wider range of Attributes for analysis, we recommend that NPS consider minimum altitudes of no less than 1,500 feet AGL for both helicopters and airplanes conducting commercial air tour over the memorial; and at least 2,000 feet AGL over the adjacent wilderness area. If, for aircraft safety reasons, it is necessary to provide altitude separation between helicopter and airplane tour routes, then we recommend that NPS consider a minimum altitude of 1,500 feet AGL for helicopters and 1,800 feet AGL for airplanes. Air tours that wish to fly lower than that can and should remain outside the ATMP Planning Area.

  1. Time of Day – As proposed, Alternative 4 would allow air tours to fly from one hour after sunrise until one hour before sunset for non-QT flights; and from sunrise to sunset for QT flights, the same as Alternative 3. The proposed schedule will make it extremely difficult for park visitors to plan to see the Sculpture when air tours are not occurring. We believe that park visitors traveling to western South Dakota for a once-in-a-lifetime visit to Mount Rushmore should have a reasonable opportunity to see the Sculpture in its natural setting, absent intrusive air tour noise, for at least a few hours every day. For this reason and to provide a broader range of Attributes and related impacts to analyze in the EA, we recommend that in Alternative 4 NPS consider time of day restrictions that would allow air tours to fly from three hours after sunrise until three hours before sunset. This minor adjustment would triple the amount of air tour noise-free quiet time in in the morning and the afternoon.

While we have read what the newsletter says about Quiet Technology Incentives (QTI), NPS has provided no description or data regarding how much measurable sound reduction QTI would provide. For example, would it reduce sound levels by 10 dBa, 20 dBa, or more? And is it reasonable to think that a local air tour company in western South Dakota would have the financial resources to invest in technologically advanced but expensive QT helicopters?

As a result, we cannot offer an informed comment about what time of day restrictions would be appropriate for QT aircraft; and we do not know if it is financially realistic for the tour operator(s) to implement in this case. However, since NPS does propose a Quiet Technology Incentive in the newsletter, we ask NPS to provide more detailed information in the EA about what the public could expect in terms of the measurable sound reduction when QT aircraft are used. If the noise reduction is substantial, then we recommend that Alternative 4 allow QT aircraft to fly from one hour after sunrise until one hour before sunset not. If the noise reduction is not substantial, then we recommend that QT aircraft be limited to the same time of day restrictions as other aircraft. Our intent in making these recommendations is to eliminate early morning and late afternoon air tour noise so that park visitors have at least a small opportunity each morning and afternoon to experience the natural sounds of the memorial without hearing intrusive air tour noise.

  1. Operator Training and Education – As described in Table 6, operator training and education is “mandatory if requested and/ or made available by the NPS.” What does this really mean? If requested by whom? It sounds like training is actually optional unless NPS decides it is mandatory, presumably at the park level. We understand that the MORU newsletter is using boilerplate language that has been previously used in other ATMP newsletters and that the decision of whether to require training is likely to be made at the park level. However, since this newsletter applies specifically to MORU, why can’t the park decide if it wants to require training or not, and then present that as the proposed Attribute for this alternative?

Having dealt with a variety of other commercially guided tours in parks, we would highly recommend that under Alternative 4 NPS require and provide annual air tour operator and pilot training at MORU (i.e., train not only the owners/operators/permittees, but also their pilots). It would not only increase the chances of operator and pilot compliance with the ATMP requirements, it would also provide an opportunity for NPS to share accurate information with operators regarding park history, significance, and interpretive themes – all information the operator could and should share with its customers to provide a more informative experience to people visiting the park “from above.”

  1. Amendments – As described in Table 6, the ATMP may be amended at any time upon notification of either agency to the other. Similar to our concern under Alternative 2, the way this Attribute is written creates tremendous uncertainty about the longevity of whatever ATMP details the agencies decide upon this time. It opens the door for political pressure and industry lobbying to expand the numbers of flights allowed or to “relax” (i.e., weaken) measures intended to minimize the adverse impacts of air tour noise.

Since it has taken NPS and the FAA over 20 years (since the passage of the Act) to begin preparation of the park’s first ATMP, we would hope the new ATMP would provide stable, long-term guidance for the management of air tours at MORU. However, something that can be “amended at any time” is neither stable nor long-term. We therefore recommend that NPS revise the wording of this Attribute for Alternative 4 to convey the notion that “the ATMP is intended to provide long-term guidance for the management of air tours at MORU. However, future minor adjustments may be made in the ATMP upon the request of either agency to address concerns that arise after its implementation.”

  1. 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: See: https://www.nps.gov/subjects/nepa/upload/NPS_NEPAHandbook_Final_508.pdf.

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).” (Emphasis added)

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 finally moving forward with the ATMP planning process at MORU, 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 now 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



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

Bert Frost, Director of Regions 3, 4, and 5, 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