June 18, 2002 11:00 pm

By The Associated Press

An air tanker that nose-dived in Northern California killing all three crew members was repaired four years ago for cracks in one wing, a representative of the plane's owner said Tuesday night.

The downed C-130A Hercules, operated under contract with the U.S. Forest Service, had just completed a pass over the blaze Monday when its wings snapped off and the fuselage plunged in Walker, Calif.

George Petterson, the lead National Transportation Safety Board investigator at the crash scene, said he was not aware of the earlier wing problem but that it would be examined.

‘‘I have no idea if that's related to what we've got,'' he said.

The nation's C-130A tankers, workhorse of the firefighting fleet, were grounded Tuesday in the midst of what could become one of the worst fire seasons in history.

The C-130A that crashed Monday was fighting the 15,000-acre Cannon fire north of Yosemite National Park. Investigators were trying to determine if a practice campfire set by Marine trainees started the blaze Saturday.

The plane's operator, Hawkins & Powers Aviation Inc., notified the Federal Aviation Administration in April 1998 that an inspection discovered two 1-inch cracks in the surface or ‘‘skin'' of one of Lockheed-built plane's wings, according to an FAA document obtained by The Associated Press.

In the Service Difficulty Report, Hawkins & Powers described the cracks as near a rivet hole on the bottom of a wing. The damage was repaired and no subsequent problems were reported, a company employee said Tuesday night.

‘‘All I can tell you is there were some wing repairs done to the aircraft. I don't know the extent of that,'' said Diane Nuttall, an administrative assistant at Hawkins & Powers in Greybull, Wyo. She did not know when the repair work was done.

Records show the 46-year-old aircraft passed its last major inspection in October.