An air tanker fighting a wildfire near Yosemite National Park in Northern California crashed Tuesday, but there was no immediate word on the condition of the pilot, who was the only person aboard, officials said.
The plane went down about 4:30 p.m. within a mile of the park's west entrance, Yosemite spokesman Scott Gediman said. Rescue crews were working their way through difficult terrain to reach the plane.
"It's very rugged terrain," said Janet Upton, a spokeswoman for the California Department of Forestry and Fire Protection. "We determined there was a crash, but they're still trying to work their way through pretty rugged terrain to determine the status of the pilot. Obviously we're hoping for the best, but the situation is very serious."
The airplane, manufactured in 2001, is an S-2T air tanker, which is flown by a single pilot and has no other crew members. The tanker uses twin turbine engines and is capable of carrying 1,200 gallons of fire retardant, said another CalFire spokesman, Daniel Berlant.
A California Highway Patrol spokesman, Officer Steven Lewis, said CHP Sgt. Chris Michael witnessed the crash as he was helping to close state Route 140 where it enters the park.
"All the tourists and residents were being turned away," Lewis said, when Michael reported that he had just witnessed "a bomber collide into the river canyon, the canyon wall, and watched it explode in flames and reported there was plane debris landing in the highway."
The canyon wall is above the highway and the Merced River, Lewis said.
"It's almost vertical canyon walls," Lewis said, "and the road was cut in 100 years ago right along the river. Anything that falls from the top is going to fall right on the roadway."
There were no reports of any injuries on the ground as a result of debris.
Don Talend, of West Dundee, Illinois, said he may have seen the plane go down. Talend and friends were vacationing at the park when they stopped to snap some photographs of the fire, which was several miles away.
He told The Associated Press by phone that he saw a plane flying low through heavy smoke near a burning ridge when a wing appeared to waggle or flip up.
The plane "disappeared into the smoke and you heard a boom," he said.
"I couldn't believe what I saw," Talend said. "There was actually a ranger there behind us. ... He had a look of disbelief on his face."
The missing pilot is an employee of DynCorp., which provides the pilots for all CalFire fixed-wing aircraft and the maintenance for the department's planes and helicopters, Upton said. Cal Fire Capt. Kendal Bortisser said neither air tanker stationed in San Diego was involved in the Yosemite effort.
It was unclear if the pilot was flying to or from the fire or was in the process of dropping retardant.
The fire had broken out about 90 minutes earlier Tuesday near Route 140, which leads into the heart of the park. It had grown to about 130 acres by Tuesday evening and forced the evacuation of several dozen homes near the community of Foresta.
The National Transportation Safety Board and Federal Aviation Administration were investigating the crash and were expected to arrive at the crash site Wednesday morning, FAA spokesman Ian Gregor said.
FAA records show the plane is registered to the U.S. Forest Service, which originally provided the plane to CalFire, Upton said.
The last time a CalFire air tanker crashed was in 2001, when two tankers collided while fighting a fire in Mendocino County, killing both pilots, Berlant said.
The agency had another plane crash in 2006, when a fire battalion chief and a pilot were killed while observing a fire in a two-seat plane in Tulare County.
