SACRAMENTO U.S. aviation safety officials said Tuesday structural or mechanical failures could have figured in the latest crash of a P-3 aerial firefighting tanker, though the Forest Service is optimistically putting its small, remaining fleet into service after two aging-tanker breakups in recent years.
Paul Schlamm, a spokesman for the National Transportation Safety Board, said his agency has not ruled out causes linked to problems with the plane, any more than it has pilot error, in the April 20 crash of a former Navy P-3 Orion submarine chaser in Northern California.
"We've made no conclusions, preliminary or otherwise," Schlamm said in an interview with the Oakland Tribune.
Within two days of the crash, in widely circulated news reports, the U.S. Forest Service declared it was "cautiously optimistic" structural failure wasn't to blame, and it would not ground the remainder of its aging air tankers.
The Forest Service cited NTSB observations at the scene and, later, data on the service life of the aircraft from its builder, Lockheed, and former operator, the Navy.
On Tuesday at the aviation management division of the Idaho-based National Interagency Fire Center, Forest Service spokeswoman Rose Davis acknowledged that the NTSB hasn't "made any conclusions."
"They have not expressed any firm assessment of the cause," Davis said. She still insisted, however, Schlamm indicated the position of the wreckage "made it look like it probably was not" a problem with the aircraft.
Schlamm said the NTSB may not finish its investigation for six months late in the fire season.
In the meantime, the Forest Service is continuing to contract with private firms for use of seven remaining P-3 tankers, together with two P-2Vs that are being electronically monitored for stress.
But the federal fleet is a fourth its normal size due to groundings last year after two other types of retired military aircraft converted to air tankers broke up in midair.
The Forest Service and Bureau of Land Management have contracted for additional single-engine tankers and helicopters to make up for the loss.
The Forest Service's efforts include looking at converted Boeing airliners being pitched by Oregon-based Evergreen International Aviation and at Nevada-based Minden Air's idea to convert a British BAE-146.
In addition, a federal contractor is evaluating old DC-4, DC-6 and DC-7s, used by the military for cargo.
The Forest Service is ruling out use of the A-10 jet Warthog tank killer as unsuitable and a Russian supertanker citing problems gaining Federal Aviation Administration permission to fly them in this country.
Contact Sacramento Bureau Chief Steve Geissinger at