Capt. Greg Gormelly of Tehama County Search and Rescue said the crash location just south of Lassen National Forest's Ishi Wilderness was first reached by ground at 8 a.m. Thursday about 10 hours after rescuers set out.

"Even though the (California Highway Patrol) helicopter pilot said there was no sign of survivors, you have to proceed as if

Emergency crews investigate the scene Thursday of an air tanker crash northwest of Cohasset. The plane, normally used during fire season to drop retardant on wildfires, was on a training flight when it crashed Wednesday evening, killing all three on board.

 there might be," Gormelly said.

Rescue turned to recovery, however, when no signs of life, and initially very few signs of what once was a P-3 Orion tanker plane, were found.

The death of three pilots employed by Aero Union Corp. of Chico, also the owner of the plane, were confirmed by the Tehama County Coroner's Office Thursday.

They were identified as captains Brian Bruns of Minden, Nev., Paul Cockrell of Fresno, and Tom Lynch of Redding.

A company official said Lynch is Aero Union's chief pilot. All three men are veteran pilots believed to be in their 30s or 40s, but the company official said their exact ages weren't immediately available.

The men flew out of Chico Wednesday on a training exercise and were over a remote area about 30 miles northeast of the city when the plane went down at 6:55 p.m. near the southwest corner of the Ishi Wilderness Area.

It sparked a wildland fire which intensely burned about two acres and started numerous spot fires all quickly extinguished by crews from the Lassen National Forest.

A fire ball from the crash was reportedly seen by residents in communities up to 20 miles away.

The plane, which carried the tail number 26, appeared to crash while making a downslope run near Brushy Mountain. Its trajectory suggested it was practicing a water drop but officials with the National Transportation Safety Board said that couldn't yet be confirmed.

"We'll be looking at records from training missions that day to determine if the plane was carrying water," said Ellen Engleman-Conners, chairman designate for the NTSB. P-3's are capable of delivering up to 3,000 gallons of water or premixed retardant.

A team of seven federal investigators arrived in Chico Thursday and did a cursory review of the crash scene. A complete investigation will commence today with investigators concentrating on the plane's power plant, airworthiness and records concerning its maintenance and the training and backgrounds of the pilots, Engleman-Conners said.

"We may also fly the path of the plane in a helicopter to determine if there were any tree strikes or other obstacles it may have hit," she stated.

"We'll be ruling things out, as well as ruling them in."

The plane carried no flight recorder equipment, she said. It's flight path was tracked by a satellite navigation system, which recorded its position every two minutes.

Federal investigators will be assisted by officials from Aero Union, Lockheed-Martin and Rolls Royce Allison, the maker of its turbine engines.

The crash site investigation may be wrapped up in a week or so, Engleman-Connners said, but conclusions about the crash may not be reached for a year.

Parts of the plane may be shipped to Washington, D.C., for examination and testing, she said.

Remains of the three men may be recovered today, Tehama County Undersheriff Dennis Garton told the Red Bluff Daily News.

Going unnoticed by aerial reviews of the crash site Thursday, which revealed near total disintegration of the plane, was a second debris field on a nearby plateau where a number of intact pieces of the plane were reportedly found. The discovery will aid the investigation, officials said.

The crash devastated Northern California's tight-knit air tanker community. Aero Union closed its Chico headquarters for the day Thursday and was referring calls to an office near Washington, D.C.

At an air attack base near the Chico airport operated by the California Department of Forestry and Fire Protection, Capt. Dan Reese said crews were unable to hold back tears as they remembered the men as friends and valued allies on the fire lines.

He said money from a benevolent fund CDF maintains may be made available to assist families of the three pilots.

The NTSB confirmed that four Aero Union tanker planes currently under contract to firefighting agencies in various states would be temporarily taken out of service. Following the crash, Aero Union has seven P-3 Orion tanker planes available for duty.

If not contracted for by May 1, the plane that crashed would have been flown to Coeur d'Alene, Idaho, its designed Forest Service administration base during fire season.

Matt Mathes, spokesman for the U.S. Forest Service in California, said the aircraft had previously completed inspections conducted by DynCorp International and Sandia National Laboratory. The tests included verifying the plane's structural integrity.

He said the P-3 Orions as a whole are fast, solid planes.

"We have a lot of faith in the structural integrity of the P-3 Orions," Mathes said.

A search of federal aviation accident and incident databases show the aircraft wasn't involved in accidents investigated by the NTSB, nor any incidents or mid-air mishaps reported to the FAA.

The airplane, built in 1966, was involved in four safety mishaps logged in the Interagency Aviation Safety Communique database between 2001 to 2004. Incidents include landing the plane through a flock of seagulls at Moses Lake, Wash., in July 2004, attempting to take off from Chester Airport while the main runway was being repaired in October 2002 and having a mechanic's service car scratch a propeller blade in Redding in July 2001.

Staff writer Greg Welter can be reached at 896-7768 or gwelter@chicoer.com. Staff Writer Ryan Olson contributed to this story.