SACRAMENTO — U.S. Sen. Dianne Feinstein demanded Monday that the federal government solve problems grounding more than two-thirds of its big, aging firefighting planes this summer, prompting moves that may put another third of the fleet in the air.

California officials also scrambled for funds to fully muster the state's modernized air-tanker fleet in the wake of Oakland Tribune articles Sunday on aerial firefighting problems.

California's senior U.S. senator said she contacted the departments that oversee federal firefighting — the U.S. departments of Interior and Agriculture — seeking solutions to the problems.

"We urgently need to have tankers," said Feinstein spokesman Howard Gant-man.

He said letters dispatched to the departments asked essentially, "What are youdoing? These newspaper stories raise a number of very troubling questions and she wants to be assured they have the situation under control."

By the end of the day, the U.S. Forest Service said it had launched a study assessing the operational service life of another nine large air tankers — an effort that could clear the way for their use by June.

Other legislators in Washington and Sacramento said the federal government needs to modernize and expand its air-tanker firefighting fleet, following California's example.

A representative of the powerful House Armed Services Committee in Washington, chaired by Rep. Duncan Hunter of El Cajon — who lost his home in deadly wildfires that ravaged portions of Southern California two years ago — said his staff was looking into issues surrounding the lack of newer, military-surplus planes for conversion into air tankers.

At the same time, Republican lawmakers in the California Legislature — echoing majority Democrats — said they would not support fellow Republican Gov.

Arnold Schwarzenegger's proposed budget cut that could force the California Department of Forestry to ground three of its 23 modernized, fast-attack air tankers daily.

Schwarzenegger's aides said they were looking into augmenting their proposed budget for CDF, whose top officials said they were faced with either grounding some of the state-owned planes or cutting back on staffed fire engines.

State Sen. Dennis Hollingsworth, a Temecula Republican whose district was hit hard by recent wildfires, said that otherwise the Legislature will have to provide the funds.

"I think it's pretty clear that we have to provide the resources from the legislative branch to CDF to be able to be ready (with all 23 planes) for whatever fire season may come," Hollingsworth said.

"We've seen the value of having to have the entire fleet in service at one time and it's even more imperative to have that entire fleet flying with the reduction in the federal fleet," he said.

The Tribune reported Sunday that just seven of the 33 air tankers usually under contract to the U.S. Forest Service and Bureau of Land Management are mechanically sound enough to fly this summer. Another three are so unsafe they cannot operate over populated areas in case they crash.

Grounding of the rest follows recent crashes in which federally contracted air tankers broke up in mid-air.

In an attempt to offset the loss of big air tankers, which can drop 3,000 gallons, the U.S. Forest Service said it is bolstering its fleet with small, crop-duster type planes and helicopters, which officials said have some advantages.

"Air tankers are not the only tool in the box," said U.S. Forest Service spokesman Matt Mathes.

"The federal government has about 700 helicopters available this summer, including helicopters that can drop the same amount as large air tankers," Mathes said.

"They are more accurate than air tankers because they hover directly over the fire and drop the retardant or water," he said. "That pinpoint accuracy is particularly important in protecting homes."

Mathes said turnaround times also are shorter for helicopters, which don't have to fly back to a base with a long runway. 

Even without many of its big air tankers, the federal aerial firefighting program "is in very good shape," he said. Federal officials expect to maintain a 98 percent success rate of keeping fires at less than 100 acres.

Still, air tanker pilots and other veteran firefighters said air tankers are uniquely qualified for certain purposes, including laying long retardant firebreaks that halt, slow or direct flames.

Contact Sacramento Bureau Chief Steve Geissinger at sgeissinger@angnewspapers.com.