National Park Service staff, while explaining their approach to crafting an air tour management plan for Bryce Canyon National Park in Utah, acknowledged that they never considered a ban on the commercial overflights.

In a response to a number of questions raised by the National Parks Traveler, Park Service staff said the management plan grew out of the Interim Operating Authority for overflights that dates to 2000, when Congress passed the National Parks Air Tour Management Act that directed the Park Service and Federal Aviation Administration to develop plans for park overflights. Terms of the IOA, in essence, created the baseline for the management plans.

"The park evaluated the potential impacts of the Air Tour Management Plan when compared to conditions under the Interim Operating Authority. This evaluation determined that the proposed ATMP would not result in significant impacts to park resources, and that no significant impacts from air tours have been observed at the park in the past," Park Service spokesperson Jeffrey Olson said in an email to the Traveler on Monday. "This lack of significant impacts allowed the park to pursue a 'categorical exclusion' to comply with the National Environmental Policy Act and to attempt to meet the U.S. Court of Appeals for the District of Columbia Circuit’s timeline to complete the ATMP by August of this year.  

"Due to the categorical exclusion’s finding of no significant impacts, such a substantial change as banning all air tours was not justifiable," he added. "The plan’s purpose was instead to balance protection of park resources with reasonable opportunities to continue to experience the park from the air. This balance was achieved by authorizing no more than the same number of flights per year as the average number of flights from 2017-2019."

Under the Bryce Canyon plan, which takes effect in January, up to 515 air tours per year may be flown over the park on defined routes. At Public Employees For Environmental Responsibility, Jeff Ruch has said the two agencies were bypassing the NEPA requirements and simply grandfathering in existing numbers of allowed flights.

"... NPS and FAA took the [overflight] average for the past three years and adopted it as their plan. There were no noise surveys or studies, no NEPA compliance or serious consideration of alternatives," Ruch told the Traveler earlier in November after Bryce Canyon released its plan.

Mike Murray, chair of the Coalition to Protect America's National Parks, was disappointed by the Park Service's approach.

"We have serious concerns about the process," Murray said during a recent podcast on the National Parks Traveler. "We've commented on every proposed air tour management plan that's come out. I personally was involved in all those comments. So I've researched it heavily, every one of them. Having been involved in some very complicated planning processes when I worked for the Park Service, it's inexplicable to me why the Park Service is not doing a better job on the NEPA analysis."

Kristen Brengel, senior vice president for government affairs at the National Parks Conservation Association, added during the podcast that categorical exclusions don't "really move forward an in-depth analysis of the effects of air tours on parks. And so what you get is just a very basic version of how they see the world. ... From our perspective, it's a missed opportunity to actually manage to the resources and the values and the visitor experience. And that's where the Park Service gets into trouble, by allowing these damaging uses in parks and not putting together plans that are actually the most protective that they could put in place."

Olson, however, said the Park Service at Bryce Canyon took a close look at noise levels created by the overflights.

"To determine the severity of noise at ground level [the Park Service] considered not just the presence of noise and potential for disturbance, but also the duration, frequency, and amplitude of noise," he said. "Analysis determined that ground level noise above 35 decibels—a level at which quieter natural sounds would be masked—would be heard for less than 20 minutes on a peak day in most of the park."

"The ATMP also consolidated flight paths and moved them east," he said. "In much of the southern end of the park, this places flight paths east of the park boundary and its proposed wilderness areas. In the more-developed northern end of the park, it ensures flight paths are completely outside the Bryce Amphitheater’s popular historic trails and buildings district.  Though noise and visual intrusions from air tours may temporarily disrupt the opportunity for solitude in recommended wilderness, because of the limited number of flights, the limited duration of noise, and the routes used it is unlikely that the majority of visitors will experience these disruptions. If a visitor in recommended wilderness does hear noise from an air tour, it is unlikely that the visitor will hear more than a few per day and the noise exposure will be for a very short duration of time."

The agency spokesperson also said that while the interim plan failed to set a minimum altitude for the park overflights, "the new ATMP requires helicopters to fly a minimum of 1,000 to 2,600 feet above-ground-level and fixed-wing to maintain a minimum of 1,500 to 2,600 feet AGL depending on terrain. Though higher altitudes can increase the area where noise is heard, it is generally expected to attenuate noise levels within the park."

While the ATMP plans for Bryce Canyon, Arches, and Canyonlands national parks all contained incentives to allow for overflights later in the day if aircraft were outfitted with "quiet technology," Olson said the plans didn't require such technology because "[A] requirement for 'quiet technology' first requires the park and FAA to define it; however a fixed definition for quiet technology in this ATMP was not practicable. This is due to the fact that aviation technology continues to evolve and advance and because the FAA periodically updates its noise certification standards. An aircraft that may qualify as quiet technology today may be out of date 10 years from now."

Nevertheless, the Park Service does not believe the overflights will greatly disturb visitors on the ground at Bryce Canyon, he said. 

"Though noise and visual intrusions from air tours may temporarily disrupt the opportunity for solitude in recommended wilderness, because of the limited number of flights, the limited duration of noise, and the routes used it is unlikely that the majority of visitors will experience these disruptions," he said. "If a visitor in recommended wilderness does hear noise from an air tour, it is unlikely that the visitor will hear more than a few per day and the noise exposure will be for a very short duration of time."

Bryce Canyon is among 24 parks in the National Park System for which the agencies are developing air tour management plans or voluntary agreements. Each air tour management plan or agreement is developed to allow air tours to be managed in a way that is consistent with the NPS’s mission and the FAA’s authority to ensure flight safety, according to the park release.

An exception to the current approach most parks are taking with developing these plans can be seen at Glacier National Park. Park staff there say the overflights harm the visitor experience. In its air tour management plan the park calls for all commercial air tours to be phased out by the end of 2029.

The preservation of natural sounds, protection of natural and cultural resources, wilderness character, and preserving visitor experience by addressing noise issues are priority NPS management objectives for the Park. -- Glacier National Park