FLAGSTAFF, Ariz. -- The National Park Service is once again trying to balance sightseeing with silence in the Grand Canyon.
The effort comes after more than two decades of rancor, including multiple lawsuits and a congressional order that has led to cutbacks in sightseeing flights over the canyon and howls by tour group operators -- but not enough quiet to please environmental groups, according to the Arizona Daily Sun.
The Park Service opened a new public comment period late last month to hear from affected groups as it works on a new plan to regulate noise in the park.
The final plan, due out in 2008, will set air tour routes and flight schedules for canyon overflights.
The decisions will ultimately determine the fortunes of those who make a living flying over the canyon, the ability of tourists to view the canyon from above, and the experience of those who hike the canyon or float down the Colorado River.
Suggestions from the public will be reviewed by a group representing Indian tribes, the Park Service, air tours, the Federal Aviation Administration and environmental groups.
Previous negotiations failed amid lawsuits and turf wars between the Park Service and the Federal Aviation Administration.
Grand Canyon Superintendent Joe Alston said that because of earlier restrictions, most of the park's 4 million annual visitors never hear the tourists flying overhead in helicopters and planes.
"The majority of the noise has been moved away from where people are," Alston said, with flights now routed over more remote areas.
Environmental groups disagree, and hikers and backpackers on backcountry trails periodically send in written complaints.
"It is well out of compliance, far from compliance," said Dick Hingson, who represents the Grand Canyon Trust and National Parks Conservation Association.
Tour operators flying out of Tusayan in northern Arizona and Las Vegas flew 53,077 tours in 2004, 60 percent fewer than in earlier peak years, showing about 500,000 people around the canyon by air. There are 90,000 total tour flights allowed each year.