Still waiting to learn the cause of a large air tanker crash that killed three pilots on a training mission in April, U.S. Forest Service officials in May were cautiously optimistic that large air tankers would continue to support firefighters through the season.

The April 20 crash of Aero Union Corp.'s P-3B Orion tanker near Chico, Calif., killed Brian Bruns of Minden, Nev.; Paul Cockrell of Fresno, Calif.; and Tom Lynch of Redding, Calif. — and renewed fears that the few large air tankers returned to service just days earlier might be grounded again.

Forest officials were awaiting more information about the cause of the crash from the ongoing investigation by the National Transportation Safety Board. The preliminary investigation indicated that “all of the aircraft structure was accounted for at the wreckage site,” a sign that the accident wasn't caused by structural weakness.

Pending more information from the NTSB, the remaining large air tankers under contract would keep flying, said U.S. Forest Service spokesperson Rose Davis. “Seven of them are P-3 Orions that we have operational service life data on, and the other three we don't have that information, but we have them wired up with monitoring equipment, so we're going to take the risk of returning them to service so we can gather data on the firefighting environment.”

Davis said the Forest Service paid for an engineering study for the P-2Vs, and was hoping to get those results in early June. “We may see enough data to give us confidence in returning the P-2Vs back, but nothing is a given. Safety is the bottom line, and [having] some sort of confidence that they're safe to fly.”

In January, the Forest Service began soliciting bids for 20 large air tankers for this year's wildland season. To win a contract, operators must produce a paper trail documenting the aircraft's service life and establish the number of hours each aircraft can be expected to operate safely. Inspectors must also clear the tankers before they're eligible.

But some called the shortage of large air tankers a “crisis” in what may be another heavy wildfire season and urged the use of foreign air tankers to help fight American wildfires. Rep. Dana Rohrabacher (R-Calif.) sharply criticized the Forest Service for relying on a “handful of contractors” to supply air tankers, when offers from Russian and Canadian wildland officials were on the table.

“The U.S. Forest Service regulations establishing the requirements for airplane-based firefighting are obviously designed to protect the good old boys and to discourage anyone else with new approaches and new alternatives,” Rohrabacher said before Congress April 26. “I am suggesting that the U.S. Forest Service drop its obstructionist policies that have prevented, among other things, the use of foreign firefighting aircraft to extinguish major fires in the United States.”

According to a report in the Los Angeles Times, the Russian Ilyushin-76 Waterbomber can soak an area the size of 12 football fields with one 10-second drop of 11,000 gallons. That's about four times the capacity of the largest American air tankers.

“Yet the U.S. Forest Service has blocked the Russians from providing their services here, even as we endured massive fire destruction in places like Florida, New Mexico and in California," Rohrabacher said.

Davis said it's not that simple. “The main thing is that's not up to us completely,” she said. “These aircraft from other countries have to be certificated [sic] by the Federal Aviation Administration in the United States to fly for whatever operation they're going to fly.… That would be the first step. Before we'd even look at them, the FAA would have to tell us that they're legal to fly in this country.”

Davis noted that the Forest Service is looking at several new ideas to update its fleet of air tankers. It's currently in discussions with Evergreen International Aviation of McMinnville, Ore., which has equipped a Boeing 747 as a “supertanker” for wildland firefighting. It has a tank capacity of 24,000-gallons.

The Forest Service is currently awaiting an operational assessment of the Evergreen aircraft, Davis said. It's weight and large size are of concern. “What can it do? Where can we use it? Can it land on our tanker bases? Some of them may not have runway weight strength to hold it. So all those things still have to be assessed on the aircraft.”

Davis said companies with ideas for air tankers that the Forest Service is evaluating include Minden Air of Minden, Nev., which is developing the BAE-146, a British Aerospace jet, as a wildland jet tanker, and another company she declined to name.