By Steve Geissinger
Inside Bay Area (California)
Copyright 2006 MediaNews Group, Inc. and ANG Newspapers
All Rights Reserved
SACRAMENTO — U.S. investigators were unable to determine the cause of a front-line federal firefighting air tanker crash last year in Northern California that killed three aviators, the National Transportation Safety Board reported Sunday.
The NTSB concluded the four-engine P-3 — the type of military-surplus plane that has become the mainstay of the federal firefighting fleet this summer — did not break up in mid-air like older types of firefighting planes that have been grounded.
The agency also said Tanker 26 did not suffer engine or control problems, but was so close to the ground that a wing tip smashed into rugged terrain.
A private aviation-consulting firm hired by MediaNews Group said that pilot error likely caused the crash of the plane that was practicing a low-altitude, fire-retardant drop the evening of April 20, 2005, near Chico, 150 miles northeast of the San Francisco Bay Area.
Virginia-based JM Associates concluded the crash apparently occurred due to controlled flight into terrain.
“Prior to the accident, the aircraft was flight worthy and there were no identifiable mechanical malfunctions or catastrophic failures contributing to the crash,” said James Munsterman of JM Associates, in an analysis of the NTSB’s preliminary and factual reports.
The NTSB approved a report on the probable cause of the accident last week and posted it on the agency’s Internet Web site Sunday.
The findings clear a cloud over P-3s, former Navy submarine attack planes, which have become the backbone of the federal heavy aerial firefighting tanker fleet, as California and the West continue to face the threat of devastating wildfires.
NTSB investigators said that although they could not determine a cause, mid-air failure was unlikely because of the small debris field. The control surfaces and engines appeared to be working, as well.
The weather was clear, there was enough light to fly safely and the crew had been healthy and was not under the influence of drugs.
There were no distress calls and air tankers are in a class of aircraft notequipped with flight data or cockpit voice recorders.
The big red and white turboprop planes are scrambled almost daily to fight wildfires. Though they mix in the sky over wildland fires, the federally contracted fleet is in no way connected with the state-owned fleet of twin-turboprop S-2s.
U.S. Forest Service officials, who contract with private aviation firms to supply air tankers and crews, were not immediately available for comment.
Aero Union Corp. of Chico, which owns and operates the federally contracted P-3s, has consistently cited it emphasis on safety and maintenance.
Representatives of Aero Union, a defense contractor for the U.S. and several other nations, said refurbished military-surplus P-3s are tough, swift and particularly suited to firefighting.
Tanker 26, a P-3 Orion manufactured by Lockheed, was delivered to the Navy in 1966 and later refurbished as a firefighting plane that carried 3,000 gallons of retardant. Hundreds of Orions, many of which are newer models or have been refurbished, are being flown by the U.S. and other nation’s forces for surveillance.
“It isn’t the age of the aircraft,” Al Ross, a Washington-based spokesman and lobbyist for Aero Union, said in a recent interview. “It’s how it’s maintained.”
In the industry, the firm is generally considered an example of a company that is able to surpass the standards of the Federal Aviation Administration and military, while competing for government low bids.
P-3 air tankers, supplied solely by Aero Union, constitute about half the Forest Service’s remaining heavy tanker fleet.
The agency already has suffered permanent grounding of other big military-surplus planes -- converted to air tankers -- after mid-air breakups pointed to inherent weaknesses in the aging aircraft.
Officials announced greater and likely permanent reliance on helicopters and smaller single-engine planes in the absence of a big fleet of large air tankers.
But the federal government is expected to alter that direction in December. A report is expected to call for continuation of an array of aerial firefighting tools, including big tankers.