2015-09380. Grand Canyon National Park Quiet Aircraft Technology Incentive: Seasonal Relief From Allocations in the Dragon and Zuni Point Corridors

AGENCY:

Federal Aviation Administration, Transportation; National Park Service, Interior.

ACTION:

Final notice to announce implementation and disposition of public comments.

SUMMARY:

On November 10, 2014, the Federal Aviation Administration (FAA) and the National Park Service (NPS) published in the Federal Register [79 FR 66763-66765] a notice of the agencies' proposal to provide a quiet aircraft technology incentive for commercial air tour operators at Grand Canyon National Park and a request for public comments. Specifically, the agencies proposed to provide seasonal relief from allocations in the Dragon and Zuni Point corridors for commercial air tour operators that convert or have converted to quiet aircraft technology. The FAA and the NPS have reviewed and considered all comments, and have decided to proceed with implementation of the incentive as proposed. This notice describes that decision and responds to the substantive comments received.

DATES:

This incentive is effective as of January 1, 2015.

FOR FURTHER INFORMATION CONTACT:

Keith Lusk, Program Manager, Federal Aviation Administration, P.O. Box 92007, Los Angeles, California 90009-2007; telephone [phone]; email [e-mail] Robin Martin, Chief, Office of Planning and Compliance, Grand Canyon National Park, P.O. Box 129, Grand Canyon, Arizona 86023-0129; telephone [phone]; email [e-mail].

SUPPLEMENTARY INFORMATION:

I. Authority

Authority: Moving Ahead for Progress in the 21st Century Act, Sec. 35001, Pub. L. 112-141, 126 Stat. 843; National Parks Air Tour Management Act, Sec. 804, Pub. L. 106-181, 114 Stat. 192.

1. The National Park Overflights Act of 1987, Pub. L. 100-91, directed the Secretary of the Interior and the Administrator of the FAA to take actions to provide for the substantial restoration of the natural quiet and experience of Grand Canyon National Park and the protection of public health and safety from adverse effects associated with aircraft overflight. As part of these actions, operational limits for commercial air tour operations at Grand Canyon National Park (the park) were imposed by FAA regulations at 14 CFR part 93 issued on April 4, 2000. With some exceptions not relevant to this notice, these regulations establish an allocation scheme for the park, require commercial air tour operators to use one allocation for each flight that is a commercial air tour, and prohibit operators from conducting more commercial air tours in any calendar year than the number of allocations specified on the certificate holder's operations specifications issued by the FAA. 14 CFR 93.319.

2. The National Parks Air Tour Management Act (NPATMA), Pub. L. 106-181, was signed into law on April 5, 2000. Section 804(a) required the FAA to designate reasonably achievable requirements for fixed-wing and helicopter aircraft to be considered quiet aircraft technology (QT) for purposes of the statute's provisions. In 2005, the FAA issued a final rule classifying aircraft operating in Grand Canyon National Park and designating aircraft that meet the noise criteria as QT. 70 FR 16084-16093. These regulations were codified at 14 CFR 93.303 and Appendix A to Subpart U of Part 93. Under NPATMA section 804(c), commercial air tour operations by fixed-wing or helicopter aircraft that employ QT and that replace existing aircraft are not subject to the operational flight allocations that apply to other commercial air tour operations at the park, provided that the cumulative impact of such operations does not increase noise at the Grand Canyon. Section 804(d) provides that a commercial air tour operation by an aircraft in a commercial air tour operator's fleet on the date of enactment of NPATMA that meets QT requirements or is subsequently modified to meet QT requirements may be used for commercial air tour operations under the same terms and conditions as section 804(c) without regard to whether it replaces an existing aircraft. In addition, NPATMA expressly states that it does not relieve or diminish the statutory mandate to achieve substantial restoration of natural quiet and experience at the park.

3. Section 35001 of the Moving Ahead for Progress in the 21st Century Act (MAP-21), Pub. L. 112-141, July 6, 2012, directs the Secretary of the Interior and the Administrator of the Federal Aviation Administration to provide incentives for commercial air tour operators that convert to QT, determined in accordance with the regulations then in effect. MAP-21 gives as an example of an incentive increasing the flight allocations for operators of QT on a net basis consistent with section 804(c) of NPATMA, provided that the cumulative impact of such operations does not increase noise at the Grand Canyon. MAP-21 also provides that all commercial air tour operators must convert to QT by 2027.

II. Background

Congress has encouraged the use of quiet aircraft technology (QT) as one means of addressing noise from commercial air tours at Grand Canyon National Park. The FAA was required by NPATMA to designate reasonably achievable requirements for fixed-wing and helicopter aircraft to be considered QT, and issued a final rule to accomplish this in 2005. This rule did not include QT incentives and did not relieve commercial air tour operators of their operational limitations. NPATMA's provision that allocations do not apply to QT operations only takes effect if the cumulative impact of such operations does not increase noise at the Grand Canyon. Although the FAA concluded that aircraft that meet the QT designation are consistently quieter than aircraft that do not, 70 FR 16088, neither the FAA nor the NPS had sufficient data at that time to determine whether noise would increase if limits on the number of QT operations were removed. In addition, NPATMA expressly states that it does not relieve or diminish the statutory mandate to achieve substantial restoration of natural quiet and experience at the park. Substantial restoration of natural quiet had not been determined to be achieved at that time. Various QT incentives were considered by the agencies following the 2005 final rule, but were not finalized.

MAP-21, enacted in July 2012, provided additional direction to the FAA and the NPS on QT incentives. In response to MAP-21, the NPS, in consultation with the FAA, reduced the fees applicable to commercial air tour operations at the Grand Canyon by 20 percent (from $25 to $20 per flight) for an air tour using QT effective January 1, 2014. On February 3, 2014, the FAA, in consultation with the NPS, announced its intention to distribute FAA-held allocations to commercial tour operators in proportion to the number of QT operations flown in the first six months of 2014. 79 FR 6267-6268. These allocations were subsequently distributed for use for QT flights during the 2014 air tour season and beyond.

III. Seasonal Relief From Allocations for QT in the Dragon and Zuni Point Corridors

Following notice and public comment, the FAA and the NPS have decided to provide an additional QT incentive in the Dragon and Zuni Point corridors where QT can have the greatest positive effect on park resources and where the need for relief from allocations has been demonstrated. Under this incentive, commercial air tour operators flying QT aircraft in the Dragon and Zuni Point corridors initially will be relieved from having such operations count against their annual allocations in the first quarter (January 1-March 31) of 2015. The FAA and the NPS will use the quarterly reports that are currently required to be submitted by the operators to determine the number of QT flights flown during the first quarter that will not count against their annual allocations. During this first quarter, QT flights will not use an allocation, while non-QT flights must still use an allocation. All commercial air tour flights, QT and non-QT, must use an allocation for the remainder of the year (April 1-December 31). However, operators will continue to benefit from the seasonal relief throughout the remainder of the year since they may use allocations in April through December that they would otherwise have used for QT flights conducted in January through March.

The first quarter of the calendar year, when park visitation and demand for air tours are seasonally low, has historically had the lowest level of commercial air tour operations. Providing this incentive initially in the first quarter of 2015 is a prudent action that gives the FAA and the NPS an opportunity to evaluate the impact of the incentive, including the extent to which commercial air tour operators continue to use QT in the remainder of the year which will produce additional noise benefits for the park. The FAA and the NPS want to incentivize commercial air tour operators to maximize the use of QT throughout the year. To that end, the seasonal relief from allocations may be extended to part or all of the fourth quarter (October 1-December 31) in 2016 and following years, in addition to the first quarter, based on an evaluation of the preceding year. In 2015, the more that increased QT use reduces the noise level below the noise baseline described in the following paragraph, the greater the prospect for operators to have additional seasonal relief from allocations in 2016.

To meet the statutory conditions in NPATMA and MAP-21, the FAA and the NPS must ensure that the cumulative impact of QT operations relieved from allocations does not increase noise at the park. Neither NPATMA nor MAP-21 specifies a methodology for calculating whether the cumulative impact of relieving QT operations from allocations would increase noise. After extensive consideration of the statutory language and the associated technical issues, the FAA and the NPS have determined that, for this seasonal relief incentive, the annual noise from both QT and non-QT commercial air tour flights conducted in the Dragon and Zuni Point corridors must not exceed the annual noise level of commercial air tour flights under the current Dragon and Zuni Point corridors allocation system.

The agencies have agreed that the cumulative noise impact ^[1] will be evaluated in terms of the total amount of commercial air tour noise energy occurring inside park boundaries averaged over an entire year. The agencies further agreed that the most suitable way to ensure that the seasonal relief from allocations incentive for QT operations in the Dragon and Zuni Point corridors does not increase noise in the park is to compute noise at a large number of grid points throughout the park, instead of only using grid points in the Dragon and Zuni Point corridors. Accordingly, the NPS and the FAA used a grid of 1224 points with 2 km spacing across the park. Technical experts from both agencies also determined that a single number provides the most straightforward means of determining whether there is an increase in noise. This number is calculated by taking the total noise energy calculated for a year's air tour data at each of the individual grid points and averaging it over the entire park—resulting in a single LEQ₁₂ value.^[2]

Using this methodology, the FAA and the NPS have modeled the annual noise of commercial air tour allocations in the Dragon and Zuni Point corridors as flown with the 2012 commercial air tour fleet mix and route structure—resulting in a noise baseline of LEQ₁₂ 58.1 decibels (dB). This single number serves as a reference criterion for measuring changes to the noise environment based on the cumulative impact of operations. It is the average noise level across the entire park as if a year's worth of flight allocations in the Dragon and Zuni Point corridors took place in twelve hours on a single day. It is not intended to represent a value which may be experienced by visitors to the park on any particular day.^[3]

A more detailed technical description of the methodology and calculations that resulted in the LEQ₁₂ 58.1 dB reference criterion has been placed in the docket. In order to accurately and reliably ensure compliance with the statutory mandate that the cumulative impact of operations under this QT incentive not increase noise at the park, the same calculation described above will be applied to each year's air tour data. The FAA and the NPS will model the annual noise from all commercial air tour operations conducted in the Dragon and Zuni Point corridors and compare the annual noise with the seasonal relief incentive in place with the noise baseline of all commercial air tour allocations in these corridors. Noise will be determined to increase if the annual modeled LEQ₁₂ noise of commercial air tour operations conducted in the Dragon and Zuni Point corridors exceeds LEQ₁₂ 58.1 dB in the park. If noise in any year exceeds the noise baseline, the seasonal relief incentive will be modified or discontinued as determined necessary to comply with the statutory condition.

To ensure that this incentive will not diminish the achievement of substantial restoration of natural quiet and experience at the park, all commercial air tour aircraft including QT must adhere to the existing route structure throughout the park, including the Dragon and Zuni Point corridors. Substantial restoration of natural quiet in the park will continue to be calculated based on the peak day of air tour operations using the percent time audible metric. The NPS will continue to monitor noise to evaluate substantial restoration of natural quiet.

This incentive applies only to commercial air tour operators that have allocations in the Dragon and Zuni Point corridors; i.e., operators must have allocations in these corridors in order to be relieved from allocations. It does not apply elsewhere in the Grand Canyon Special Flight Rules Area (SFRA). There is an ample unused surplus of commercial air tour allocations in the SFRA outside of the Dragon and Zuni Point corridors; therefore, operators conducting air tours in these other SFRA areas do not need relief from allocations and would not be incentivized to convert to QT by a seasonal relief incentive.

Seasonal relief from allocations is intended to provide an incentive for operators with non-QT aircraft to convert to QT in advance of the statutory requirement for full QT conversion, and to maximize use of QT already in the fleet. It rewards those operators who have already fully converted to QT by allowing them to take full advantage of the incentive. The number of air tours conducted by operators using QT can increase beyond the level permitted under the existing allocation system as long as the cumulative impact of the additional number of quieter aircraft operating in the park does not increase noise at the park.

Seasonal relief from allocations will not automatically increase the number of flights. Any increase in air tour flights will depend on the demand for air tours, which is influenced by factors such as general economic conditions and the amount of tourism. Seasonal relief allows air tour operators to save allocations that would have been used in the first quarter of the year and to use them during times of year when air tour demand is higher. The most immediate effect of the incentive is likely to be to provide a cushion of allocations to any qualifying operator in the Dragon and Zuni Point corridors that is at risk of running out of allocations before the end of the calendar year.

If the seasonal relief in the Dragon and Zuni Point corridors is a successful QT incentive, it is proposed to remain in effect unless it violates the statutory condition that the cumulative effect of such operations must not increase noise at the Grand Canyon, or diminishes the achievement of substantial restoration of natural quiet, in which case it will be either modified or discontinued; or until a longer term approach for managing air tour noise in the park is in place.

The FAA and the NPS commit to developing a long term approach for managing noise in the park in an expeditious manner. Any long term approach will continue to incentivize conversion to QT and will not penalize earlier conversion to QT realized through the seasonal relief incentive.

IV. Discussion of Comments

The public comment period was open until December 10, 2014. The FAA and the NPS received 147 comments on the November 10, 2014 notice describing the proposal to provide seasonal relief from allocations in the Dragon and Zuni Point corridors, including 60 comments which were posted after the close of the comment period. Commenters included individuals identifying themselves as hikers, backpackers, river rafters and back-country visitors to the Grand Canyon; groups representing those types of park users; environmental and conservation organizations (collectively referred to as “recreational and environmental interests”). Joint comments were filed by a helicopter trade association and a coalition of Grand Canyon air tour operators (collectively referred to as “air tour interests”). Most of the comments expressed appreciation for the unique qualities of the Grand Canyon, including natural quiet, and the desire that these qualities be protected. The agencies reviewed and considered all comments, and have responded below to comments of substance on the QT seasonal relief incentive. Comments and responses are organized under subject matter headings.

Statutory Basis for Incentives

Comment: Several commenters representing recreational and environmental interests questioned the authority for QT incentives and expressed concern about the consistency of this seasonal relief incentive with other laws protecting national parks. The air tour interests offered their view of Congressional intent and criticized the agencies for delay in implementing the legislative directive.

FAA and NPS Response: This QT incentive is offered pursuant to MAP-21 and to implement Section 804(c) of NPATMA, as described in this notice. MAP-21 and NPATMA include protections to Grand Canyon National Park, namely that the cumulative impact of QT operations relieved from allocations must not increase noise at the park and that the achievement of substantial restoration of natural quiet and experience at the park shall not be relieved or diminished. This latter provision in NPATMA ensures that this QT incentive is consistent with the mandate in the 1987 Overflights Act to achieve substantial restoration of natural quiet. Further, the NPS has an affirmative responsibility to protect the resources and values of national park units, including park soundscapes. To that end, since this measure provides incentive for air tour operators and owners to improve their fleets commensurate with industry advancements in quiet aircraft technology, this incentive holds promise for the continual reduction of noise in Grand Canyon National Park. The FAA and the NPS describe the history of events that affected the time line of QT incentives in the Background section of this notice.

Quiet Technology Incentives

Comment: Commenters questioned whether the proposed incentive is necessary in light of other incentives and the fact that operators are already converting to QT. Some commenters representing recreational and environmental interests objected to what they view as subsidizing a private industry and suggested that operators should pay the cost of converting to QT. The air tour interests noted that over $200 million has been invested in QT aircraft by the air tour industry.

FAA and NPS Response: Both NPATMA and MAP-21 contemplate allowing increased flights, i.e., relief from allocations or operational caps, by QT. This incentive addresses those provisions, i.e., it creates an incentive for air tour operators to maximize use of QT aircraft by allowing them to fly additional air tours beyond their current allocations. Operators are financially responsible for the aircraft they use for air tours and have already acquired a significant number of QT aircraft at their own cost. MAP-21 requires all commercial air tour aircraft operating in Grand Canyon National Park to fully convert to QT not later than 2027.

Comment: Some commenters representing recreational and environmental interests suggested the proposal actually gives an incentive to retain and operate noisier helicopters. The air tour interests commented that operators already need to maximize use of QT to recoup costs.

FAA and NPS Response: Air tour operators that have already converted to QT aircraft will have an additional incentive to maximize use of those aircraft; other operators will have an incentive to convert to QT. Because the cumulative impact of the incentive will be evaluated based on the annual commercial air tour operations conducted in the Dragon and Zuni Point corridors, the use of QT aircraft at any time of the year will contribute to a determination that noise has not increased and will increase the potential for the incentive to be continued and extended to the fourth quarter in subsequent years.

Comment: Commenters questioned the basis for classifying aircraft as QT and asked who would validate aircraft in an air tour operator's fleet as QT.

FAA and NPS Response: Appendix A to Subpart U of 14 CFR part 93 contains the procedures for determining the QT designation status for each aircraft. Additional guidance can be found in the FAA's Advisory Circular 93-2, Noise Levels for Aircraft used for Commercial Operations in Grand Canyon National Park Special Flight Rules Area. The FAA is responsible for designating aircraft as QT and for determining which aircraft comply with that designation.

Comment: Some commenters suggested that air tour operators should be required by regulations to use QT aircraft all of the time or convert over a period of time, while others called for a transition as soon as possible to QT.

FAA and NPS Response: MAP-21 requires all commercial air tour aircraft operating in the Grand Canyon National Park Special Flight Rules Area to fully convert to QT not later than 2027. In the meantime, MAP-21 directs the FAA and the NPS to provide QT incentives to encourage earlier conversion and use of QT.

Comment: Some commenters representing recreational and environmental interests suggested that flights using “saved” allocations should use QT. Other commenters suggested that each QT flight should use a fraction of an allocation.

FAA and NPS Response: The agencies structured this incentive to be consistent with the NPATMA Sec. 804(c) provision relieving commercial air tour operations by QT from operational flight allocations, subject to protections with respect to noise and substantial restoration of natural quiet in the park, and with the MAP-21 provision that references increasing flight allocations consistent with NPATMA Sec. 804(c). Neither NPATMA nor MAP-21 requires additional conditions to be placed on flights using allocations, as suggested by commenters. As a practical matter, the FAA expects an air tour operator's fleet to include the same proportion of QT for an entire year that it uses in the first quarter of the year, which means that QT would be used for allocations. Furthermore, the overall air tour activity in the Dragon and Zuni Point corridors, whether using QT or non-QT, cannot increase noise at the park.

Comment: Some commenters representing recreational and environmental interests advocated a 1-2 year trial period for the incentive that expires on date certain. The air tour interests suggested that the incentive include the fourth quarter at the outset.

FAA and NPS Response: The agencies have determined that providing this incentive initially in the first quarter of the year is a prudent action that gives the FAA and the NPS an opportunity to evaluate the noise impact of the incentive, which will depend not only on the first quarter QT use but also on the extent to which commercial air tour operators continue to use QT in the remainder of the year. The incentive may be modified or discontinued as determined necessary to comply with the statutory condition at the end of the first year or any subsequent year.

Noise Calculation and Impact

Comment: Some commenters were uncertain as to what the LEQ₁₂ 58.1 dB metric represents and asked how the baseline was developed.

FAA and NPS Response: The LEQ₁₂ 58.1 decibels (dB) reference criterion is a basis for judging changes to the noise environment, and is not intended to represent a value which may be experienced by visitors to the park on any particular day. Additional information has been provided in this final notice, and a more detailed technical description of the LEQ₁₂ 58.1 dB reference criterion, including how it was calculated, has been placed in the docket.

Comment: Some commenters representing recreational and environmental interests disagreed with using a cumulative metric or annual average and said that noise increases should be measured based on peak day or each and every day. Commenters also suggested that supplemental noise metrics be considered.

FAA and NPS Response: The statutory language “cumulative impact of such flights” calls for a metric that calculates noise cumulatively over a period of time. LEQ₁₂ is one of several metrics that is used to evaluate air tour noise in Grand Canyon and other national parks and was selected by technical experts in the FAA and the NPS as the most appropriate to use to determine cumulative impact. A daily noise calculation is not appropriate for this purpose. Substantial restoration of natural quiet, another required criterion, will continue to be calculated based on the peak day of air tour operations using the percent time audible metric.

Comment: One commenter suggested that the annual evaluation of the incentive's impact should reflect conversion to any QT aircraft that produces more noise than an aircraft in the baseline.

FAA and NPS Response: The annual evaluation will calculate the noise of all QT and all non-QT aircraft and will account for any additional noise, whether from a noisier aircraft or from more aircraft operations.

Comment: Commenters questioned the baseline against which the cumulative impact of QT operations will be compared (i.e., the annual noise of commercial air tour allocations in the Dragon and Zuni Point corridors as flown with the 2012 commercial air tour fleet mix and route structure). Commenters representing recreational and environmental interests suggested there should be an improvement in the noise level over the status quo measured by actual operations rather than allocations. The air tour interests questioned use of a 2012 fleet mix rather than a fleet mix representative of either the year 2000 or 2005 and suggested that the comparison should be to sound levels that would have been present if all aircraft were non-QT. The air tour interests also suggested that the baseline should be substantial restoration of natural quiet.

FAA and NPS Response: Both NPATMA and MAP-21 include the QT limiting provision: “. . . provided that the cumulative impact of such operations does not increase noise . . .” at the park. Neither statute provides for further reductions in noise with respect to QT incentives. The prohibition on increasing noise is not defined or elaborated on in either statute. The FAA and the NPS considered various possible baselines and determined that the baseline should reflect the amount of noise that can be generated by the number of commercial air tour operations that are permitted under the current allocation system. If noise exceeds a level that is currently permitted under the allocation system, the agencies will consider it to be an increase in noise. The alternative selection of a noise baseline using the actual level of air tour operations in 2012, as recreational and environmental interests suggested, would constitute a reduction from what is currently allowed since the actual 2012 level of air tour operations was lower than what is authorized. It would not be a QT incentive to set a baseline that is lower than what air tour operators would be allowed to do under the current allocation system. In addition, the agencies chose 2012 as the year to model baseline noise. MAP-21 provided renewed direction for QT incentives in July 2012 and directed the agencies to provide such incentives not later than 60 days after the date of enactment of MAP-21. While the agencies could not meet the 60-day time frame, it was clear that the Congress gave meaning to 2012 with respect to QT incentives. An additional consideration by the agencies was the availability and currency of air tour fleet and operational data in 2012, as opposed to looking back to previous years. The alternative of selecting either the year 2000 or 2005, as the air tour interests suggested, was considered by the agencies, but was not adopted because of concerns about re-creating earlier data for modeling input to obtain a noise baseline and whether the selection of a past year would adequately ensure no increase in noise and no diminishment of the achievement of substantial restoration of natural quiet. This latter consideration was involved in deciding not to model the noise baseline with an all non-QT fleet, which would not reflect the noise environment in the Dragon and Zuni Point corridors in 2012. The agencies are also cognizant that an incentive must be based on a stable baseline that can be relied on by air tour operators as they make QT conversion decisions; therefore, the 2012 noise baseline will continue to be used for this seasonal relief incentive in future years. With respect to using a baseline of substantial restoration of natural quiet, this is a separate applicable standard in NPATMA; not a substitute for the no cumulative noise increase requirement. Both requirements must be met. To ensure that this incentive will not diminish the achievement of substantial restoration of natural quiet by exposing new areas of the park to air tour noise, all commercial air tour aircraft, including QT, must adhere to the existing route structure in the park.

Comment: The air tour interests suggested that any noise increase should be substantial or perceptible in order to justify discontinuing the incentive. Commenters representing recreational and environmental interests called for transparency and accountability, continued modeling and/or monitoring to ensure noise does not increase, and suggested that noise data should be made public.

FAA and NPS Response: The FAA and the NPS are responsible and accountable for ensuring that this QT incentive does not increase noise at the park or diminish the achievement of substantial restoration of natural quiet. The LEQ₁₂ 58.1 dB baseline is a fixed baseline against which noise increases will be judged. Noise above the baseline level will be considered to be an increase, regardless of whether it is considered to be either “substantial” or “perceptible”. The agencies will monitor the air tour operators' use of QT for air tours as required to be reported in the operators' quarterly reports submitted to the FAA, and will annually model noise as described in this notice. Annual noise results will be publicly available. In addition, the NPS will use periodic on site monitoring consistent with industry standards. The NPS routinely uses monitoring to supplement modeling results. Monitoring data would enable the NPS to check the number of flights flown on each route segment, providing cross-validation for the numbers reported by air tour operators. Monitoring data also would provide the single event level (SEL) and maximum sound level (Lmax) for each flight, enabling the NPS to confirm the benefits of QT aircraft.

Comment: Some commenters noted that ambient noise levels at the Grand Canyon are very low and even QT aircraft can be heard. Commenters representing recreational and environmental interests expressed concern that overall noise will increase even if QT operations result in a reduction in noise per flight and that park visitors will be in worse position if the result is more constant noise from more frequent flights.

FAA and NPS Response: The overall noise cannot increase under the statutory mandate that provides for the QT incentive to be allowed subject to the cumulative impact not increasing noise at the park. The LEQ₁₂ metric used to evaluate cumulative impact takes into account aircraft noise levels, the number of aircraft operations, and the duration of noise. In addition, the incentive cannot, by statute, diminish the achievement of substantial restoration of natural quiet at the park.

Comment: Commenters representing recreational and environmental interests expressed concern that noise would increase in backcountry or elsewhere in the Grand Canyon; that noise would increase in off-season when backpacking and hiking is most comfortable and visitors enjoy a respite from noise; or that the incentive would result in increased flights of loud aircraft in summer.

FAA and NPS Response: There are statutory protections to preclude an overall, i.e., cumulative, increase in noise and to prevent diminishing the achievement of substantial restoration of natural quiet, as described in this notice and in the response to the previous comment. QT aircraft must adhere to the current route structure defined for air tour operations; no new areas of the Grand Canyon will be opened to air tours under this incentive. The agencies do not anticipate a significant increase in the number of air tours operated in the winter months when tour demand is low. The incentive should increase the proportion of QT aircraft used for air tours in the Dragon and Zuni Point corridors and decrease the number of louder non-QT aircraft. Air tour operators that convert or have converted to QT for the seasonal relief are anticipated to continue to operate those quieter fleets during the summer season. Seasonal relief allows air tour operators to save allocations that would have been used in the first quarter of the year and to use them during times of year when air tour demand is higher; therefore, there may be increases in the number of air tour flights at other times of year above the number that has been allowed under the allocation system. If an increase in the number of flights rises to the level that results in a cumulative increase in noise, the seasonal relief incentive will be modified to reduce noise or will be discontinued.

Comment: Commenters suggest agencies mandate one “quiet day” per month.

FAA and NPS Response: This suggestion would presumably involve a prohibition on air tours for one day each month, which is outside the scope of approved measures currently in place at the park and is not a QT incentive.

Comment: One commenter called for assurance that incentives will not degrade substantial restoration of natural quiet.

FAA and NPS Response: The agencies will ensure that this incentive does not diminish substantial restoration of natural quiet as required by NPATMA.

Impact on air tour operations

Comment: Commenters representing recreational and environmental interests suggest this is an attempt to increase number of operations by labeling them as quieter. The air tour interests express concern that operators who have already converted to QT may not see a permanent increase in their allocations. Commenters representing recreational and environmental interests noted that they expected to see flights shift from peak to off-peak as part of a QT incentive. One commenter expressed the view that the seasonal relief incentive will result in vigorous marketing of air tours in January through March.

FAA and NPS Response: Currently, air tour operators can use allocations at any time throughout the year based on the demand for air tours and individual business decisions. This incentive does not change that situation. The demand for air tours is expected to remain highest in the peak season.

Comment: Commenters representing recreational and environmental interests advocated a cap on operations.

FAA and NPS Response: Rather than imposing a numerical cap, the statutory noise conditions effectively provide a limit.

Comment: Commenters asserted that more frequent flights will produce more air emissions.

FAA and NPS Response: FAA and NPS air quality specialists do not expect air tours to significantly affect air quality in national parks.

V. Implementation Steps

The FAA and the NPS will use the quarterly reports that are currently required to be submitted by the operators to determine the number of QT flights flown during the first quarter that will not count against their annual allocations. The FAA will implement the incentive by amending the operations specifications of commercial air tour operators holding allocations in the Dragon and Zuni Point corridors to allow them to conduct air tours with QT aircraft without using an allocation for such tours in the specified seasonal time periods. The FAA and the NPS will cooperatively ensure that the statutory conditions protecting the park are met.

VI. Environmental Considerations

This action involving the FAA's amendment of operations specifications is categorically excluded from more detailed environmental review because it would not have a significant effect on the environment. The FAA and the NPS have designed this incentive to ensure compliance with the statutory conditions that the cumulative impact of QT operating without allocations does not increase noise and that the incentive does not diminish the statutory mandate to achieve the substantial restoration of natural quiet at the park.

Issued in Hawthorne, CA, on March 19, 2015.

Glen A. Martin,

Regional Administrator, Western-Pacific Region, Federal Aviation Administration.

Issued in Lakewood, CO, on March 23, 2015.

Sue E. Masica,

Regional Director, Intermountain Region, National Park Service.

Footnotes

1.  Cumulative noise impact is not the same criterion as the substantial restoration of natural quiet (SRNQ). SRNQ is calculated and determined on the peak day of air tour operations using the percent time audible metric.

2.  LEQ₁₂ stands for Equivalent Sound Level for 12 hours, which is a cumulative measure of the noise exposure of A-weighted sound levels over a 12-hour period. LEQ₁₂ is one of several metrics used to evaluate air tour noise in Grand Canyon and other national parks. The metric takes into account aircraft noise levels, the number of aircraft operations, and the duration of noise. A 12-hour LEQ is used since air tour operations occur during the day, rather than over a 24-hour period.

3.  This LEQ₁₂ value is not an average day noise level. To produce a noise level representing an average day at an average location in the park, further calculations of the 2012 LEQ₁₂ 58.1 dB value would need to be made and would produce an LEQ₁₂ average day noise level of 32.5 dB.