Search teams returned for a second day Friday to the crash site of American adventurer Steve Fossett's plane in eastern California.

The plane's wreckage is seen in this photo, released by the Mono County Sheriff's Search & Rescue. The California Civil Air Patrol had flown over the crash site 19 times during the initial search. (Associated Press)

They were scouring the Sierra Nevada mountain range for traces of the 63-year-old aviator, who disappeared 13 months ago after taking off from an airfield in Nevada on a solo flight that was supposed to last only a few hours.

Recovery teams finished hauling away scattered parts of metal before a snowstorm was predicted to hit late Friday.

The mangled parts and other debris were shipped to a warehouse in Sacramento, where they will be examined by investigators.

Many of the pieces were "consistent with a high-energy impact, which means the aircraft was travelling at great speed," said Mark Rosenker, acting chairman of the U.S. National Transportation Safety Board.

"We'll be looking at the entire fuselage to make sure nothing broke off to cause the accident," he said.

Any suspected human remains were to be taken to a state crime lab for testing.

Crews with cadaver dogs located a few personal effects amid the single-engine plane's wreckage on Thursday, along with a bone fragment, measuring five centimetres by four centimetres, Madera County Sheriff John Anderson said.

Anderson said the bone fragment had not yet been confirmed as human and that DNA tests would have to be conducted. Earlier, Rosenker said searchers had found "human remains, but there's very little."

Earlier in the week, a lone hiker walking his dog near Mammoth Lakes stumbled across a pilot's licence and other ID cards belonging to Fossett, about 400 metres from where the plane was later spotted.

U.S. adventurer Steve Fossett, shown here in 2006, disappeared Sept. 3, 2007, after taking off from a Nevada ranch in a single-engine plane. (Kirsty Wigglesworth/Associated Press)

Investigators said the aircraft appears to have hit the mountainside head-on. The debris, hidden from easy view for more than a year, littered an area longer than a football field and nearly as wide.

"It was a hard-impact crash, and he would've died instantly," said Jeff Page, emergency management co-ordinator for Lyon County, Nev., who assisted in the search.

In a statement, Fossett's widow, Peggy, said the discovery of the plane's wreckage may bring her some emotional comfort after more than a year of uncertainty.

"I hope now to be able to bring to closure a very painful chapter in my life," she said. "I prefer to think about Steve's life rather than his death and celebrate his many extraordinary accomplishments."

Fossett made a fortune in the Chicago commodities market and gained worldwide fame for setting records in high-tech balloons, gliders, jets and boats.

In 2002, he became the first person to circle the world solo in a balloon.

With files from the Associated Press