YOSEMITE NATIONAL PARK, California (AP) — Air tankers were grounded Wednesday in California after one of the aircraft crashed into a steep canyon wall while fighting a blaze in Yosemite National Park, killing the pilot, officials said.

The agency normally does such a safety stand-down after a crash, State Department of Forestry and Fire Protection spokeswoman Alyssa Smith said.

It was not clear how long the planes would be out of service.

The agency has about 22 of the S-2T air tankers. Other aircraft were still available to assist with fires, officials said.

The pilot's family has requested no name be released until all immediate family members can be notified, Smith said. Rescue crews planned to recover the body on Wednesday. The pilot was believed to be the only person aboard.

Rescue crews hiking through extremely rugged terrain found the wreckage and confirmed the pilot's death several hours after the plane crashed on Tuesday, Smith said,

The plane went down within a mile of the park's west entrance, Yosemite spokesman Scott Gediman said.

California Highway Patrol Sgt. Chris Michael said he was stopping traffic along state Route 140 at the west entrance to the park when he saw the crash.

"I heard a large explosion, I looked up on the steep canyon wall and saw aircraft debris was actually raining down the side of the mountain after the impact," he told The Associated Press by telephone.

The fire was spreading up the canyon wall, and it appeared the pilot was trying to lay down fire retardant to stop its progress, Michael said.

Pieces of the aircraft landed on the highway and came close to hitting fire crews on the ground, but no one on the ground was injured, he said.

The airplane, manufactured in 2001 and based out of Hollister is flown by a single pilot and normally has no other crew members. The tanker uses twin turbine engines and is capable of carrying 1,200 gallons of retardant, said another CalFire spokesman, Daniel Berlant.

The missing pilot is an employee of DynCorp., a contractor that provides pilots for all CalFire planes and maintenance for the department's aircraft, said Janet Upton, a CalFire spokeswoman.

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Associated Press writers Don Thompson in Sacramento and Andrew Dalton in Los Angeles contributed to this report.