Air tour operators say noise overstated in Grand Canyon

Air tour operators who fly thousands of visitors over Grand Canyon National Park are challenging rules restricting the location of their flights because of the noise. They say the rules are based on a faulty government study.

A new noise analysis, commissioned by a member of the Helicopter Association International, says National Park Service data overstate noise levels from aircraft.

A spokesman for the U.S. Air Tour Association said the original aircraft noise study by the National Park Service is so flawed it deserves a congressional oversight hearing.

"The National Park Service appears to have deceived Congress, the air tour industry and the public when it stated that natural quiet had not been restored at the Grand Canyon," said Steve Bassett, president of the U.S. Air Tour Association, which is fighting flying restrictions over national parks nationwide. "We believe there is ample evidence here for Congress to be more than a little suspicious of the information they are receiving from the National Park Service."

Environmentalists, meanwhile, look at the USATA's study as irrelevant. Park Service officials aren't commenting on the study, which they have yet to see.

The noise issue is important to the Las Vegas economy because most Grand Canyon air tour operations are based in Southern Nevada. The Grand Canyon Air Tour Council estimates 800,000 passengers fly on air tours to the canyon from Southern Nevada, resulting in a $250 million economic impact locally.

Tour operators are gearing up for their busiest season of the year in a time when advanced bookings are down. Since the majority of air tour passengers are from Japan, operators are attributing this year's downturn in reservations to poor economic conditions in Asia.

Bassett said his organization intends to make sure key legislators are aware of the findings of its noise report conducted by aviation acoustics expert John Alberti of J.R. Engineering, of Kirkland, Wash. Bassett said knowing the Alberti report would be controversial, an independent peer report also was commissioned. K.K. Ahuja, a professor of aerospace engineering at Georgia Tech University, did the peer review and concurred with Alberti's findings.

Alberti's report said the National Park Service altered an industry-standard computer program that resulted in a computer model showing more aircraft overflight noise in the Grand Canyon than actually appeared. The report also said the Park Service used a lower sound level than initially prescribed and used a 12-hour day instead of 24 hours to measure daily impact on canyon users.

Alberti said Thursday that a big factor in the Park Service interpretation of the data is whether the terrain absorbs or reflects the sound of aircraft engines.

"Our analysis shows ... that the government studies were biased and misleading due to several invalid and unscientific assumptions that overstate the sound levels and sound detectability," Alberti says in his report. "For example, their studies zero out the sound attenuating effects of trees, loose soil and other surface features. Their studies further assume a threshold of detectability that is lower than that shown by the government's own research.

"When these errors are corrected, the result is that over 95 percent of the park will meet the Park Service's own definition of 'natural quiet' in the busiest month for air tours (July)," the study says.

Alberti said the project took about 500 to 600 man hours to complete. He would not say how much Papillon Grand Canyon Helicopters of Tusayan, Ariz., paid to have the study done.

Key legislators have not seen Alberti's report. A spokesman for Rep. John Duncan, R-Tenn., who leads the House Aviation subcommittee, said the congressman would review the report when it is made available to the subcommittee. A spokeswoman for Sen. John McCain, R-Ariz., said he has been wrapped up in tobacco industry reform legislation and has not seen the report either.

Environmentalists criticized the efforts of the air tour operators.

"The USATA doesn't have a lot of credibility when it brings arguments like this to the debate," said Tom Robinson, director of conservation policy for the Flagstaff, Ariz.-based Grand Canyon Trust, an environmental policy group.

"They say the data should be judged on a 24-hour day? Fine. They can fly their planes at night and then the 24-hour period can be considered," he said.

"I'm not surprised by the airplane people coming up with anything and everything to protect their industry," added Randy Harness, conservation chairman for the Southern Nevada group of the Sierra Club.

"Our members did their own study. They got tired of the constant drone of airplanes in the Grand Canyon so they went to the Park Service to do something about it. We know that very few people actually stop in and complain to park officials about the noise. But they complained to us."

Harness said he felt the Park Service's limitation on what hours tour flights can operate and where they can go is a good compromise to limiting noise in the canyon.

"They're (tour operators) just like every other user," said Harness. "The Park Service needs to set quotas and they have to stand in line for the number of people they can fly. Can you imagine what the beaches along the Colorado River would look like if they didn't set limits on the number of boats they allow?

"The Park Service needs to protect resources and few people consider natural quiet to be a resource. But it is. And the canyon is not quiet."

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