A House Interior subcommittee approved legislation yesterday that would ban sightseeing flights below the rim of the Grand Canyon, where 25 persons died in an aircraft collision last week.

The bill also would ban air traffic below 2,000 feet over Yosemite National Park in California and 9,500 feet over several popular tourist attractions in Haleakala National Park in Hawaii.

"We're not trying to restrict access to these beautiful parks to people who can't get there otherwise," said Rep. Tony Coelho (D-Calif.), whose initial version of the bill called for a three-year study of air traffic problems over national parks. "We are responsible for making sure it remains a safe experience."

But Rep. Morris K. Udall (D-Ariz.), who drafted the more stringent provisions, said the measure was mainly directed at reducing aircraft noise in the canyon and preserving one of the park's most treasured esthetic features -- its silence.

"The highest priority is getting it quiet down there," he said. "We have got to ban all flights below the rim except for emergency and administrative flights."

The bill, approved on voice vote, comes eight days after a deHavilland DHC6 Twin Otter and a Bell 206 helicopter collided over a remote area of the canyon, killing all aboard. National Park Service officials have speculated that the pilots were flying below the rim, but federal investigators have not confirmed this theory.

In a brief debate yesterday, several members of the national parks subcommittee acknowledged piloting planes below the Grand Canyon rim. "I've flown up and down the canyon, and not as safely as I should have," said Rep. James V. Hansen (R-Utah).

Udall, also a licensed pilot, acknowledged dipping into the canyon as well, but said that the proliferation of air-tour operators in recent years demands regulation. "If in making it available to the public you destroy much of what's there, then what do you do about it?" he said.

According to the Park Service, small airplanes and helicopters make more than 50,000 flights over the Grand Canyon each year. In the peak summer tourist season, as many as 20 flights an hour pass over the canyon, and most air-tour operators advertise that their planes go below the rim.

Environmentalists contend that engine noise, magnified by the sheer canyon walls, destroys the serenity of the park for hikers, campers and rafters.

If enacted, the measure would give the Park Service and the Federal Aviation Administration 90 days to adopt an aircraft management plan that would ban below-rim flights, assure public safety and restore "the natural quiet and experience of the park."

Air-tour operators have argued that limiting flights to certain altitudes above the park would compound safety problems by crowding more aircraft into a narrower band of air space, and some panel members suggested yesterday that limiting the number of flights may be necessary.

"It does not end sightseeing flights over the canyon," said Rep. John S. McCain III (R-Ariz.), who noted that the Park Service already sets limits on the number of rafts permitted on the Colorado River and the number of hikers on certain trails.

The measure also would give the park service three years to study aircraft impact over as many as 10 national parks, and recommend protective action. The bill specifies Cumberland Island National Seashore, Yosemite, Hawaii Volcanoes National Park, Haleakala, Glacier National Park and Mount Rushmore National Memorial.

At Yosemite and Haleakala, however, aircraft restrictions would not await the outcome of the study. Planes and helicopters would be required to stay at least 2,000 feet above Yosemite. In the Hawaiian park, pilots would have to stay 9,500 feet above the Haleakala Crater, several scenic trails and "any designated tourist viewpoint."