CHAPTER 10

 

CONCLUSIONS AND RECOMMENDATIONS

 

The information and analyses provided in the previous chapters lead first to general conclusions about the type and extent of impacts produced by overflights, and about the values associated with overflights. These general conclusions in turn lead to identification of issues that are addressed through NPS recommendations to Congress as requested in Public Law 100-91.

 

10.1 Conclusions

NATURE AND SCOPE OF PROBLEM: Aircraft overflights can and do produce impacts both on visitors and on park resources. These impacts, however, do not occur evenly throughout the park system, but occur at some parks to a considerably greater extent than at others. This was confirmed by the NPS Manager's Survey and the Visitor Survey. Based on the Visitor Survey for the National Park System where there was congruence between visitor and manager perceptions of problems in 29 of the 39 parks sampled, it is likely that there could be as many as 50 to 100 units of the park system where overflight problems are likely or certain to exist. (See Chapter 2). NPS managers have consistently identified 30-40 parks as priorities for research and problem solving for nearly a decade. Because of the congruence in perspective between visitors and managers, also confirmed in part by acoustic research, it is possible to conclude that there are significant overflight problems that need to be addressed in 15-30% of the National Park System.

Commercial and sightseeing operations are more common than other types of overflights. Military and park administrative overflights are the least common. Helicopters and low-level jets are more likely to be of concern to park managers than other types of aircraft. The nature of effects on parks is varied, as described below. Many relate to aerial sightseeing, others to low-level military overflights. Some are noise-related, some are visitor experience-related, and others are safety-related.

EFFECTS ON NATURAL QUIET: Natural quiet is an important natural resource in units of the National Park System. The indigenous sound levels in national parks, are often considerably lower than sound levels commonly experienced in most residential areas. In such park areas of low ambient sound levels, even distant aircraft can be easily heard. Complete preservation of natural quiet under these circumstances can mean that aircraft must fly several miles from the area to be protected. Natural quiet is an increasingly scarce resource in America. The NPS needs to protect some of these uniquely quiet places.

EFFECTS ON CULTURAL RESOURCES: Cultural and historical resources, sacred sites, and ceremonies can be affected by the sight and sound of overflights. The setting, ambiance, feeling or association can be disrupted, and vibrations may be induced that can be damaging to structures. If helicopters come too close to cliff dwellings, there is a potential for loss of cultural resource context and materials (pollen, small artifacts, etc.) Potential for impact depends upon the proximity of the aircraft overflight to the

 10.1

Previous Chapter
Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


 

resource, the frequency of overflight, and, for vibration impacts, the frequency-dependent responses of the resource to impinging sound or pressure waves. Resources should be examined on a case-by-case basis, but general guidelines suggest that historic structures exposed either to sonic booms or to helicopter flight at close range may be at risk of weakening or damage and should be examined to determine levels of sound-induced vibration. In the absence of such detailed information, eliminating sonic booms or keeping helicopters distant (probably about 2000 feet vertically and horizontally) should serve to protect most structures.

EFFECTS ON WILDLIFE: In general, wild animals respond to low-altitude aircraft overflights, although the manner in which they do so depends on life-history characteristics of the species, characteristics of the aircraft, flight activities, and a variety of factors such as habitat type and previous exposure to aircraft. Of most concern related to wildlife in parks are 1) low-altitude overflights by military aircraft, and 2) light, fixed-wing aircraft and helicopter activities related to tourism. The primary concern stemming from these low-level overflights related to wildlife is that the flights may cause physiological and/or behavioral responses that in turn reduce the wildlife's fitness or ability to survive. Overflights may cause excessive arousal and alertness or stress. If chronic, stress can compromise the general health of animals. Overflights may interfere with raising young, habitat use, and physiological energy budgets. Indirect effects on wildlife such as accidental injury, energy losses, habitat avoidance and abandonment are very difficult to detect, but some experts suspect they occur.

Recent concerns have focused on the significance of overflight impacts as they affect wildlife populations. Based on a limited number of studies it can be concluded that impacts to wildlife populations can occur from low level aircraft overflights. It would be valuable to have additional research to fully address population impacts, but waiting for and relying on future research results for current policy decisions is not possible. Criteria are identified in this report that the NPS proposes to use to trigger mitigation or prevention efforts.

EFFECTS ON PARK VISITORS: Visitors report impacts (interference with enjoyment, annoyance, and interference with appreciation of natural quiet), depending upon the levels of overflight sound which the visitors may have experienced. However, reported impacts are highly variable from location to location, and the results of the dose-response work and the survey of Grand Canyon visitors suggest that visitor sensitivity to overflight-produced sound is greater for activities where visitors remove themselves from automotive transportation and, possibly, from other visitors. Backcountry visitors, people on oar-powered river trips, and visitors who take short hikes away from their cars, consistently show greater sensitivity to the sound of overflights than do frontcountry visitors, including visitors at easily accessible overlooks. These findings lend credence to the need for a systematic approach to problem solving of park overflight issues, but one which can target specific problems in specific areas.

OVERFLIGHTS AND SAFETY: Although there is no evidence of serious or wide spread safety problems for on - ground visitors or park employees tied to aircraft overflights, there are at least 18 parks where safety from an on-ground perspective needs further investigation and evaluation. Virtually no visitors perceived a threat to their safety from overflights. Some organizations and individuals in the outdoor recreation community expressed concerns, but the overflight incidents triggering these concerns may be isolated incidents or reactions to other types of impacts. As in the case with other overflight impacts, identifying and correcting safety problems should be done on a park-by-park basis. The NPS needs to clearly communicate the FAA process by which park managers should identify, document and request assistance from the FAA to resolve these issues.

 10.2

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


Airspace over public lands is in demand from many sources-military operations, general aviation, air tourism operations, and by land management agencies that operate the second largest fleet of aircraft in the country. The potential for conflict, especially during fire fighting or other major incidents, is real and growing. The NPS and other land management agencies need to work with DOD and FAA to develop procedures that will resolve these airspace / park management issues in complex airspace. Improving communication links is vital.

VALUES ASSOCIATED WITH AIRCRAFT OVERFLIGHTS: Aviation helps the NPS effectively administer the National Park System, many visitors enjoy the experience of seeing parks from a different perspective, and it is a special opportunity for the disabled, elderly, and infirm. But given the potential for impacts to on-ground visitors and park resources, air tour passenger enjoyment adds to the complexity of the situation. Should the NPS consider air tour passengers as park visitors since their enjoyment derives from the resources that park preserves? But unlike for other visitors where the NPS controls visitor activity to prevent or minimize degradation of park resources and experience opportunities, the impacts of these "visitors" are not controlled by the NPS. This situation is a source of great frustration to NPS managers that needs to be appreciated by the FAA. It is essential that the FAA and NPS find a way to mitigate these impacts.

The marketability of air tours also adds to the complexity of the situation because it suggests continued growth of tours over parks. The willingness of vacationers to take air tours, and to endorse that "product" suggests to entrepreneurs that there may be opportunities for expanded air tour services. This, in turn, suggests that the problems may get worse.

 The NPS believes that these " aerial visitors " should be treated as park visitors, subject to similar benefits and restrictions as other visitors. This will be possible if there is a way to feasibly mitigate or regulate the effects of these users.

OVERALL NPS CONCLUSION: Aircraft overflights can cause impacts to park resources and values. For certain visitors, for visitors engaging in certain activities, and for certain areas, there is a very real potential for overflights to impact parks' natural and cultural resources, visitor experiences, and solitude and tranquility - the very fabric of many national parks. A systematic framework for addressing these problems is a first step; it should be flexible enough to address the unique airspace/park use issues identified in this report. NPS priorities should be used to effectively focus problem-solving efforts. At the same time, aviation confers benefits to the parks and to some park visitors. The NPS needs the assistance of FAA and the Department of Defense so that the scarce resources of natural quiet and airspace can be most effectively conserved for the common good and benefit of the American public, while also preserving the benefits provided by aviation. All of the involved agencies have very different missions with little tradition for working together for effective solutions. This needs to change, and there is some evidence that this is possible.

The issue is not whether there is an impact, but rather how much impact does there have to be before NPS can be assured of relief. Through this report, the NPS has made an important first step at defining how significant these impacts can become before they should "trigger" FAA action. The NPS recommends that these definitions of impact be accepted as a starting point, ones that can be refined over time as research and experience in application dictate.

 10.3

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


Aircraft overflights of national parks are variable in number and nature. Solutions to airspace / park use issues are likely to be equally diverse. There may be solutions or partial solutions to many problems identified to many problems identified in this report; however, the NPS recognizes that resolution may not be possible for some issues at this time. Getting to solutions dictates that issues be clearly identified and addressed by the agencies involved.

 

10.2 Airspace Management Issues: The NPS Perspective

Public Law 100-91 studies and investigations conducted by the NPS suggest that the following issues should be addressed:

 10.4

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


 

 

 

10.2.1 The FAA and The NPS: Learning How to Work Together

On December 22, 1993, Secretary of Transportation Federico Pena and Secretary of Interior Bruce Babbitt, in an important act of reinventing government, committed the FAA and the NPS to learning how to work together to resolve airspace / park use issues. In March, 1994, the two agencies issued a joint Advance Notice of Proposed Rulemaking (ANPRM) in the Federal Register1 soliciting public ideas on how to reduce adverse effects from commercial air sightseeing tours on parks such as the Grand Canyon, Hawaii Volcanoes and others. (See Appendix E.) Questions were solicited on a number of policy and technical questions that will be important to guiding the two agencies on how to proceed on this issue.

 

10.2.2 Military Airspace / Park Use Issues: Prospects for Change

There are some encouraging signs that the military services may be more amenable to resolving airspace/ park use issues than has been the case in the past. The following provides evidence of this trend:

 

 

---------------

1. "Overflights of Units of the National Park System", Federal Register Volume 59, No. 52, Thursday, March 17, 1994.

 10.5

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


 

the FAA, Air Staff, Major Commands, Air Force Reserve, Army National Guard, Army, Navy, and Marines are becoming part of the process.

NPS and the other land management agencies, for the first time, have clearly defined and centralized points of contact to deal with on airspace issues that involve the ANG. To the extent that this approach to airspace management is adopted by the Department of Defense as a whole, it will facilitate both problem solving and problem avoidance.
 

 10.6

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


 

 

 In addition, military and Fish and Wildlife Service representatives identified field level contacts to facilitate implementation of agreements and to address additional problems as they occur. The solutions are being monitored to ascertain how to ensure that these processes are permanently established. All parties understand that good communication is critical to sustain these agreements.

In a response to Senate Armed Services Committee Report on the National Defense Authorization Act for Fiscal Year 1994, Report No, 103-112, the Department of Defense reported that the coordinating group may be an important vehicle for establishing procedures and dispute resolution mechanisms between the Department of Defense and the Department of Interior. (See Appendix H). The Department of Defense has committed to reporting to the Senate Armed Services Committee by January 1, 1995 on airspace resolution procedures and recommendations developed by this ad-hoc coordinating group.

 

10.3 NPS Recommendations to Congress

10.3.1 Recommendation 1: Develop Airspace / Park Use Issue Resolution Processes

 The NPS recommends that the Department of Transportation-Department of Interior Interagency Working Group be maintained as a functioning entity to manage interagency problem solving through to the operational level of both agencies. Their priorities should be to identify and document processes that can be clearly communicated to field offices where problem solving should occur. Although many of the recommendations that follow are tied to this process, there may be some airspace / park use issues that go beyond the scope of the following recommendations. The general shape of this process should be as follows:

 10.7

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


 

The NPS also recommends that NPS and DOD use the newly established Federal Interagency Airspace/Natural Resources Coordination Group (See Section 10.3.2 and Appendix H) to develop similar issue resolution processes for low-level military overflights.

 

10.3.2 Recommendation 2: Establish and Maintain Agency Points of Contact

The NPS strongly recommends that agency points of contact be officially established and maintained as follows:

NPS: Deputy Director and Overflight Studies Coordinator

FAA: Air Traffic Operations (AAT), Flight Standards (AFS), and Environment and Energy (AEE).

DOD: To be requested through the new Federal Interagency Airspace / Natural Resources Coordination Group.

 

10.3.3 Recommendation 3: Use the Full Range of Methods and Tools for Problem Solving

The NPS recommends that all reasonable methods and tools be used in airspace / park use issue resolution processes. The following is a partial list of methods, any of which might be reasonably effective, feasible, and verifiable for use on a specific situation. The NPS has developed tools that permit identification of locations impacted by overflights, that compute, in terms of sound levels, the effects of changes in aircraft operations and that can be used to measure the reductions in impacts that result from such changes. The tools are based on a number of studies including, dose-response results, simplified sound level measurement techniques and computer programs that estimate sound exposure results from aircraft overflights.

The partial list of methods includes the following:

VOLUNTARY AGREEMENTS: Voluntary agreements can have a role in resolving or mitigating airspace / park use issues if some fundamental weaknesses can be addressed. The FAA, the NPS, and air tour operators need reasons to enter into these agreements. Furthermore, there are no enforcement or penalties involved should operators withdraw from or refuse to participate in agreements. If rulemaking and penalties result if voluntary agreements do not work, then all parties will have incentives to make and comply with these agreements.

INCENTIVES TO ENCOURAGE USE OF QUIET AIRCRAFT: NPS research suggests that quieter aircraft can play an important role in substantially restoring or maintaining natural quiet in parks. Although there is no Federal requirement for air tour types of aircraft to be manufactured to produce less noise than Stage 3 standards for large commercial aircraft, some aircraft are significantly quieter than others and more appropriate for use in air tour operations. Because of the significant expense, incentives need to be developed to encourage air tour operators to replace equipment with quieter aircraft. Internally, the NPS will need to work with the Department of Interior's Office of Aircraft Services to also provide incentives for parks to use quiet aircraft. P.L. 102-581, an "Act to amend the Airport and Airway Improvement Act of 1982 to authorize appropriations, and for other purposes, "requires the FAA to identify" any

 10.8

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


measures to encourage or require the use of quiet aircraft technology by commercial air tour operators." The NPS defers to FAA expertise on this subject, but strongly recommends that FAA facilitate the introduction of quiet aircraft technology to benefit national parks, among many others.2

SPATIAL ZONING: Flight-free zones and flight corridors have been implemented in the Grand Canyon with some success. Experience has shown that, to preserve or restore natural quiet, flight-free zones must be quite large in extremely quiet places, approximately 20-30 miles minimum dimension. The problem, discussed in Chapter 3, is that some park environments are so quiet that the sound of aircraft can be heard at great distances from flight paths.

ALTITUDE RESTRICTIONS: Minimum altitudes can help, but for tour aircraft or low altitude military training, the altitudes necessary to significantly reduce impacts may essentially defeat the purpose of the overflight. On the other hand, altitude restrictions used in Yosemite and Haleakala have helped to reduce the most egregious impacts even though overflight impacts have not been eliminated.

OPERATING SPECIFICATIONS FOR OPERATORS: As part of its certification processes, FAA may require operators to conform with certain operational requirements. These requirements generally identify the types of operations authorized, the types of airplanes permitted, airports authorized for use and time limitations for maintenance, and training. Operations specifications that relate directly to park overflight operations may provide a reasonable method to address some documented adverse effects of overflights.

TREATMENT OF AIR TOUR OPERATIONS AS CONCESSIONS: National parks treat all commercial services provided to visitors in parks as concessions (i.e. regulated industries) which insures services will conform to minimum standards, are not priced unreasonably, and are consistent with park values. In some ways, air tour operations are similar to ground-based services. In fact, where airstrips are inside parks, the NPS has several air tour operations under concession permit. If a joint FAA-NPS permitting process can be developed, similar arrangements may be possible where it is determined that air tour operations use the resources of the national parks. The purpose of this is to reduce resource impacts and to provide a specific visitor service.

NOISE BUDGETS: Noise budgets have been used at some airports (Denver-Stapleton was one of the first) to allot responsibility for and control of noise among operators. Such budgets assume that the total noise generated by the airport, and by each operator, can be quantified. Each operator can be allocated an amount of "noise," generally based on an existing or previous level of operations. If an operator uses quieter aircraft, through retrofit or new purchases, more flights can be conducted while staying within the budget. Budgets are negotiated rather than imposed. Noise budgets may provide a means for limiting growth in air tour traffic over parks in that they focus on the goal of limiting or reducing the impact of the sound of overflights, not on directly limiting the number or type of aircraft operations. A draw-back for park application may be the need for tracking numbers of operations by time and type of aircraft. Another drawback is that adverse effects to visitor experience may not necessarily be addressed.

 

---------------

2. The FAA is awaiting completion of the NPS Report to Congress before it completes the report required by the Airport and Airway Safety, Noise Improvement, and Intermodal Transportation Act of 1992.

 10.9

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


Limits on Times of Operations Some sensitive areas on the ground may have cyclical daily, weekly or seasonal high and low visitation periods. Aircraft operations may be timed to coincide with low use periods. Alternatively, air tours may have slow days, periods or seasons, and visitors in search of tranquility and natural quiet could be informed of the best times to visit the park and avoid significant numbers of overflights. Limited "No Fly" periods could provide visitors with certainty of natural quiet in some parks and should be further evaluated.

 

10.3.4 Recommendation 4: FAA to Address High Priority NPS Airspace / Park Use Issues

The NPS recommends that NPS / FAA / DOD jointly commit to resolving and mitigating airspace / park use issues beginning with identified priority areas. Such a commitment may enable the agencies to develop and more effectively communicate how issues can be resolved at the local level.

 

10.3.4.1 NPS Managerial Priorities

NPS believes its managers' identification of areas with aircraft overflight problems is a relatively accurate indicator of where airspace / park use issues exist. There is basic congruence between manager and visitor perceptions. Many of the 98 areas identified by managers have some type of overflight-related problem. Mitigation is possible for some areas and unlikely for others. The NPS seeks resolution of its top priorities and recognizes that the others (See Appendix B) merit further investigation as well. Based on top priority NPS areas for resolution of airspace issues include:

 

  • Grand Canyon National Park
  • Hawaii Volcanoes National Park
  • Haleakala National Park
  • Great Smoky Mountains National Park
  • Glacier National Park
  • Bryce Canyon National Park
  • Bandelier National Monument
  • Statue of Liberty National Monument

The NPS will further evaluate the complex air traffic patterns over Yosemite National Park and Cumberland Island National Seashore to see if mitigation appears to be possible and will then discuss those situations with FAA.

 

10.3.4.2 NPS Priorities for Protection of Natural Quiet

The following is a list of parks where the NPS believes maintaining or restoring natural quiet is an immediate priority. Natural quiet is an increasingly scarce resource in the United States. There ought to be national parks were this can be experienced. Criteria for the selection of these areas is listed in section 10.3.6. Highest priority areas meeting these criteria include:

 

  • Glacier National Park
  • Zion National Park
  • Southeast Utah Group Parks
  • Haleakala National Park
  • Crater Lake National Park
  • Isle Royale National Park
  • Mesa Verde National Park
  • Rocky Mountain National Park
  • Chaco Cultural Nat'l Historical Park

The NPS will work with the FAA to further refine the criteria and how they may apply to other parks.

 10.10

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


10.3.4.3 NPS Priorities for Resolution of Safety Concerns

The NPS recommends that its perceived on-ground safety concerns related to overflights be investigated by FAA to see if these problems can be resolved or mitigated. The FAA and the NPS are cooperating in an effort to identify and put into effect recommended air tour patterns and altitudes that will enhance aviation safety around the Statue of Liberty and reduce other impacts there as well. Additionally, the FAA is developing a Special Federal Aviation Regulation that will improve the safety of commercial air tour operations in Hawaii. The priorities for the NPS include:

The process exists for the FAA to use its authority and expertise to resolve reported safety issues. These and any other issues that are identified by park managers will be forwarded to the FAA for investigation and resolution through the FAA's compliance and enforcement program.

 

10.3.4.4 NPS Priorities for Problem Solving with Department of Defense

The NPS recommends that NPS and DOD agencies explore resolution of airspace issues at the following priority areas through the Federal Interagency Airspace / Natural Resources Coordination Group. It will be important for the FAA to be involved in this process as well. This group will report to their respective policy representatives by the end of 1994 on recommendations for resolving existing and potential airspace conflicts. NPS priorities for areas to be examined during this search for procedures include the following:

 

  • Congaree Swamp National Monument
  • Sequoia-Kings Canyon National Parks
  • Organ Pipe Cactus National Park
  • Death Valley National Monument
  • Channel Islands National Park
  • Joshua Tree National Monument
  • Petrified Forest National Park
  • Pu'ukohola Heiau Nat'l Historic Site
  • Gulf Islands National Seashore
  • Everglades Nat'l Park/Big Cypress Nat'l Preserve/Dry Tortugas National Park

DOD is required to report back to the Senate Armed Services Committee on development of procedures to resolve airspace / park use issues by January 1, 1995. The NPS will also report to the Subcommittee on National Parks, Forests, and Public Lands as well as to the House and Senate Armed Services Committees on the success and utility of this approach to problem solving.

 

10.3.5 Recommendation 5: Develop an FAA Operational Rule Triggered by NPS

The NPS recommends that FAA develop an operational rule to regulate air tour operations where they have or may have adverse effects on national parks. If voluntary agreements are not adequate, the NPS should be able to trigger action by the FAA to delineate aerial sightseeing areas defined by FAA Handbook 92.01 for Principal Operations Inspectors. The NPS would forward recommendation on the size, altitudes and routes to effect noise abatement and mitigate impacts to persons and property on the ground in parks. The FAA may adjust the recommendations and incorporate them into tour operators' operation manuals. The rule would need to specify that tour operators operate in accordance with Part

 10.11

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


 

135 FAA Regulations. Any request by an operator to the FAA to fly below 2,000 feet or within 2,000 feet horizontally of sensitive areas and structures would need clearance from the FAA only after coordination and concurrence by the park manager.

This rule would minimize the effect on other types of aviation by targeting specific problem areas. The rule's existence would facilitate the use of voluntary agreements. The NPS recommends FAA consider a special sub-part of 135 regulations to be developed for air tour operations.

Areas where this rule is most needed include the national parks in Hawaii, Glacier National Park, Canyonlands National Park, Great Smoky Mountains National Park, Zion National Park, Bryce Canyon National Park, and Rocky Mountain National Park.

 

10.3.6 Recommendation 6: Develop an FAA Rule to Facilitate Preservation of Natural Quiet

The NPS recommends that FAA, under the authority of Section 611 of the Federal Aviation Act3, implement a rule which would provide for the protection of natural quiet.

Several nationally applicable environmental statutes and regulations recognize that there are circumstances where special protection - beyond ordinary performance standards or requirements - may be necessary to adequately protect nationally significant resource values.

Class I Designations under the Clean Air Act require new air pollution sources which may affect designated airsheds -- including many in national parks -- to prevent significant deterioration of existing air quality so that resources including air quality-related values such as scenic vistas are not adversely affected. The absence of air pollution in some areas is what makes us aware of air pollution in others; if all areas are equally polluted, we have no way to know what is natural. Most Class I areas are at least 5,000 acres in size.

Outstanding National Resource Waters (ONRW) designations under the Clean Water Act often mean that no new point source discharges of pollutants are permitted in streams or other water bodies designated as ONRW. Waters in national parks are specifically referred to in the regulation that implements ONRW and several states have designated ONRW in parks. Their overall purpose is to keep the cleanest of the nation's waters clean.

The provisions of Section 522, Designating Lands Unsuitable for all or certain types of mining, of the Surface Mining Reclamation and Control Act, allow for the protection of unique resources, such as those in the National Park System, by prohibiting all or certain types of coal mining in certain areas. In one such designation, the Secretary of Interior found some federal lands adjacent to Bryce Canyon National Park to be unsuitable for surface mining because of the potential for adverse effects to scenic resources and quiet.

Each process shows that what is generally applicable may not adequately safeguard the unique resources and attributes of special, nationally significant lands and that as a consequence, designations or categories need to be implemented that establish a higher standard of protection. The NPS believes that there are parallels between these processes and overflight-related adverse impacts to units of the National Park

 

---------------

3. 45 U S C Section 44715 is . see also 49 U.S.C. 303 (a) and (c).

 10.12

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


 

System. Practices that are generally suitable for aircraft elsewhere may not be suitable in a limited number of cases where natural quiet or especially sensitive cultural resources or threatened or endangered species can be adversely affected by overflights. The NPS believes the following criteria can provide a starting point for establishing a similar process for outstanding natural quiet parks: 

In some cases these criteria could be used as the basis to petition the FAA to implement, through their rulemaking process, an aircraft management plan for that park to establish flight corridors or flight tracks that would keep areas naturally quiet and preserve the visitor experience of them.

 

10.3.7 Recommendation 7: Develop a Movie Waiver Policy

The NPS recommends that FAA amend its policy relating to the conditions and limitations for movie filming operations conducted in national parks. The new policy should require the operator flying the filming crew to have the following:

 

10.3.8 Recommendation 8: Develop an Interagency Airspace Coordination Guide/Training

The NPS recommends that the NPS, FAA, and the military services complete an Interagency Airspace Coordination Guide that would incorporate what the agencies learn about how to resolve airspace / park use conflicts. The NPS and the Air National Guard are currently developing a proposal to DOD's Legacy Program for that purpose. It is further recommended that this be the basis for training interagency planners from all the agencies involved, pilots from the Armed Services, etc.

 10.13

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


 

10.3.9 Recommendation 9: Seek Continued Improvements in Safety and Interagency Planning Related to Airspace Management.

The NPS makes he following recommendations with respect to safety and planning:

 

10.3.10 Recommendation 10: Improve SFAR 50-2 to Effect and Maintain the Substantial Restoration of Natural Quiet at Grand Canyon National Park.

Section 3(b)(3) of P.L. 100-91 requires the NPS to discuss:

... such other matters, including possible revisions in [special Federal Aviation Regulation 50-2], as may be of interest.

In Chapter 9, the NPS concluded that natural quiet in Grand Canyon National Park (GCNP) had not been substantially restored and recommended SFAR 50-2 be revised to effect a more substantial restoration. The following sections propose revisions to Special Federal Aviation Regulation 50-2 for the purpose of not only achieving substantial restoration of natural quiet but also for maintaining that restoration over time, as increases in the air tour industry occur. If he FAA determines that there are no safety concerns4, these revisions can be introduced into the FAA rulemaking process where they would undergo analysis, public review and comment. The NPS is supportive of anything the FAA can do to lessen the regulatory burden of the SFAR.

 

---------------

4. Section 3(b)(2) of P.L. 100-91 requires the FAA to review NPS recommendations to determine whether implementing them would adversely affect aviation safety.

 10.14

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


Aircraft overflight activity at GCM can be viewed as consisting of the following major elements:

This recommendation is organized by the same categories and is based on the following general concepts: simplification of the commercial tour route structure; expansion of flight-flee zones; accommodation of the forecast growth in the air tour industry; phased in use of quiet aircraft technology; and institution of changes in approaches to park management.

One of the key changes in park management will be the establishment of an acoustic monitoring program by the MS in coordination with the FAA. The MS will replace its current monitoring program with one designed to measure sound levels on the ground where the agency seeks to protect natural quiet. The MS will identify benchmark sites and establish a protocol for collecting acoustical data at those sites for the purpose of establishing "action triggers" (described in section 10.3.10.3). The "trigger" will specify a noise level that should not be exceeded. The consequences proposed for exceeding the trigger are also described in Section 10.3.10.3.

 

10.3.10.1 GCNP Airspace Structure Recommendations

The proposed airspace structure, including flight-flee zones and flight corridors, recommended to effect a more substantial restoration of natural quiet for GCNP is displayed in Figure 10.1.

GENERAL

The NPS recommends that:

 10.15

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


FLIGHT-FREE ZONES

The NPS recommends that:

FLIGHT CORRIDORS

The NPS recommends that:

 10.16

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


 

Figure 10.1 Recommended Special Flight Rules Area: NPS Proposal For Flight Free Zones and Corridors

 10.17

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


eliminated. During the five-year period, traffic along these quiet-aircraft routes would be one-way only. Minimum altitudes along these routes would remain unchanged. General aviation aircraft, like non-quiet commercial tour aircraft, would no longer have access to the Dragon Flight Corridor since it would have ceased to exist.
 

GCNP SFRA

The NPS recommends that:

 10.18

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


aircraft (including NPS aircraft) would have their access phased out. Access by general aviation and military aircraft would continue unless results from the NPS acoustic monitoring programs indicate a need for change (i.e., action triggers were met or exceeded).

ROUTES

The NPS recommends that:

 

10.3.10.2 Aircraft Equipment Recommendations 

NPS recommends that:

 10.19

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


 

applicable to developing this definition. NPS would expect that the quietest aircraft currently operating in the SFRA would qualify - the deHavilland DHC-6-300 Twin Otter ("Vistaliner" version), the Cessna 208 Caravan, as well as the McDonnell Douglas "No Tail Rotor" (NOTAR) helicopters and other quiet aircraft which would qualify to operate there. The definition should also be such that retrofitted aircraft are able to be added to the "quiet aircraft" category. This cooperative effort between the FAA and the NPS coincides with the spirit of the amendment to the National Environmental Technologies Act introduced by Senator John McCain (AZ) and recently passed by Congress.
 

 

10.3.10.3 Aircraft Operations Recommendations

Based on NPS experience in GCNP, it is apparent that a new regulation must also incorporate some form of use limits to accomplish a substantial restoration of natural quiet. It is very likely that part of the gain in noise abatement accomplished by SFAR 50-2 has been invalidated by the continuing increases in aircraft operations. The NPS has every reason to believe that this trend will continue.

Consequently, to ensure maintaining the substantial restoration of natural quiet once this recommendation is implemented, the NPS further recommends that:

 10.20

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


10.3.10.4 Flights Outside the SFRA

The NPS recommends that:

 

10.3.10.5 Miscellaneous Recommendations

The following miscellaneous recommendations are also made:

 

10.3.10.6 Modeling The NPS Recommendation for GCNP

The NPS recommendation for GCNP was modeled for this report using the National Park Overflight Decision Support System-NODSS (Reddingius 1994). This same system was used previously in evaluating whether natural quiet had been substantially restored to GCNP (see Chapter 9, Section 9.2.3) (also Fidell, Sanford, et. al. 1994). Based on data from a 1989 FAA survey of Grand Canyon air tour operators, the NPS modeled the various phases of the recommendation. line modeling for each phase takes into account forecast increases in the Grand Canyon air tour industry over the next 15 years, with some conversions to quiet aircraft. The phases (Year 1, Year 5, Year 10, and Year 15) are summarized as follows:

 10.21

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


 

By the year 2010, acoustical modeling predicts that the NPS recommendation could substantially restore natural quiet to approximately 64 percent of the park (Figure 10.2). As in Chapter 9, the white color in Figure 10.2 represents areas of the park where natural quiet has been restored 100 percent of the time, green depicts areas restored more than 75 percent of the time, and the color red portrays areas of the park where natural quiet exists 75 percent of the time or less. Regions of the park classified as "white" and "green" are areas where the NPS considers natural quiet to have been substantially restored.

Acoustic modeling also suggests that by the year 2010, nearly 45 percent of the park could experience natural quiet 100 percent ("white") of the time. Figure 10.3 depicts the steady improvement of "100 percent natural quiet" at each five-year phase in the form of a bar chart. .

The improvement brought about by the NPS recommendation is especially obvious when compared to a "no action" scenario. Modeling this scenario for the year 2010 indicates that natural quiet ("white") has been reduced to less than 1 percent of the park, down from nearly 45 percent under the NPS recommendation.

 

10.3.10.7 Summary of GCNP Recommendation

As discussed in Chapter 9 (Section 9.2.3) and graphically compared in Figure 10.4, unless action is taken to effect the substantial restoration brought about by the NPS recommendation, the legislative mandate of P.L. 100 cannot be met.

It is clear that a "no action" alternative is unacceptable. It is equally clear that achieving the substantial restoration mandated by P.L. 100-91 can only be accomplished by the proposed restructuring of the space with its larger flight-free zones and the gradual conversion of the air tour fleet to quiet aircraft, a process already well under way. The 15 year phased approach is designed to allow the air tour industry time to acquire such technology, either through purchasing new equipment or retrofitting existing equipment.

 10.22

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


 

The NPS recommendation extends prompt relief to some areas impacted most under SFAR 50-2 and ends with the substantial restoration to natural quiet mandated by Public Law 100-91. The NPS position is crafted carefully to maintain viable air tour access. The recommendation also offers immediate and long-term incentives and rewards to those companies which have voluntarily invested in quiet aircraft technology and to those companies willing to do so in a timely manner. Access to certain air tour routes over Grand Canyon, combined with other economic incentives, could very well result in equipment conversions or retrofitting to meet quiet aircraft standards within the 15 year time frame or sooner.

Results of the acoustic modeling indicate that the sum of the individual recommendations outlined in the preceding sections represent an effective approach to effecting and maintaining a substantial restoration of natural quiet for GCNP, the legislative mandate in Section 3 of P.L. 100-91. Phasing this restoration over time allows for equipment conversions while ensuring the continued economic viability of the air tour industry and the opportunity for visitors to the area to experience a quality aerial tour. The NPS recommendation strikes an appropriate balance between resource protection and visitor enjoyment.

EPILOGUE

Achieving an equitable balance between the impacts and benefits of aviation in parks is a difficult but desirable task, one that is still in its infancy. It is a long-term goal for both the NPS and FAA to seek that balance. Prior to the establishment of the Department of Interior -- Department of Transportation Interagency Working Group and the emerging dialogue between the FAA and the NPS, there was no method to address the issue. The NPS is confident that with FAA 's continued cooperation and good faith that both agencies will be part of the balanced resolution of potential difficulties. It is a new way of doing business for both NPS and FAA and one that holds promise for the future.

 10.23

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


Figure 10.2 Substantial Restoration of Natural Quiet -- Year 2010: The Result of the NPS Recommendation

10.24

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


 

Figure 10.3 Percent of GCNP in Natural Quiet (100%) If NPS Recommendation Adopted

10.25

Top of Chapter 10
Table of Contents
Return to NPC Library 
Return to NPC Home Page


 

Figure 10.4 Percent of Park Where Natural Quiet Substantially Restored: A Comparison Between NPS Recommendation and No Action

 10.26

References
Top of Chapter 10
Table of Contents

NPC Menu Bar NPC Home Page Support NPC Ask NPC Search the NPC Home Page NPC QuietNet NPC Resources NPC Hearing Loss and Occupational Noise Library NPC Noise News NPC Law Library NPC Library