By John Driscoll
Eureka Times-Standard
Part of the tail rotor on a firefighting helicopter fell off moments before it crashed into the Klamath River outside Happy Camp, killing its two pilots, a preliminary report says.
The fatal crash of the Sikorsky CH-54A Skycrane chopper on Aug. 4 was caused by the failure of a spindle connected to the tail rotor gearbox, the National Transportation Safety Board report reads. The report does not point to any human errors being to blame for the malfunction.
The helicopter was flown to Happy Camp on July 29 to help fight the Happy Camp Complex fires, which now total 3,800 acres. Killed in the wreck were Terry “Jake” Jacobs, 48, of Kern County and 38-year-old Andrei Pantchenko of Oregon, both veteran pilots.
No one from the safety board returned repeated calls.
After flying for two hours on Aug. 4, the helicopter returned to the base to refuel and was examined by mechanics. Then it left to begin a second round of firefighting.
“The helicopter conducted one uneventful dip and water drop during the second cycle and was in the process of conducting its second dip when the accident occurred,” the report reads.
The helicopter had filled its tanks with water from the Klamath River at the site near Independence Bridge several times that day. On its final run to get water, a witness heard a loud bang, and ran toward the river. When he reached a road next to the river, the report reads, he saw the helicopter flying toward the bridge. A large piece of equipment — later identified as the gear box — fell off the chopper, reads the report.
The helicopter’s nose pitched sharply forward, and without the tail rotor to counter the torque of the main rotor, the fuselage spun around until it crashed, the report says.
The twin engines of the helicopter transfer power down a series of shafts connected by universal joints to the gear box at the tail. Each tail rotor blade is connected to the gear box by a spindle. In this case, the blade associated with the failed spindle has not been found, according to the report.
On the morning of the accident, the helicopter went through a series of maintenance tests after having an engine replaced the day before. It was cleared by mechanics with chopper owner Heavy Lift Helicopters of Apple Valley and a U.S. Forest Service helicopter manager.
The tail rotor hub was overhauled on Dec. 22, 2005. That included using an X-ray like technique to inspect the spindle, a part that can be reused. The fractured spindle was sent to the safety board’s materials laboratory in Washington, D.C.
A military helicopter pilot and maintenance expert consulted by the Times-Standard said that the material failure probably happened without warning — until the loud bang. The crack in the spindle likely happened after the inspection, the expert said.
A helicopter can safely land after losing its tail rotor section, under certain conditions. The helicopter must be moving forward, possibly as fast as 100 mph. Or, if a tail rotor is lost at a hover, the engine can be idled and the craft settled vertically. But that can be exceptionally difficult in tight conditions like a river canyon, even for experienced pilots.
The Sikorsky CH-65A is considered a workhorse helicopter that first saw military duty in the 1960s. The wrecked chopper was built in 1966, and had been rebuilt and redesigned for firefighting by Heavy Lift Helicopters.
They can carry up to 750 gallons of water, making them valued by firefighting efforts around the world.
Marty Pociask, communications director and editor for Helicopter Association International, said both the CH-54A and Heavy Lift Helicopters have a solid reputation. Flying wildfire duty is unpredictable, and pilots and equipment are constantly operating in less than ideal conditions, Pociask said.
“These guys go out there and risk their lives and do a yeoman’s job,” Pociask said.
Pociask and others said a final determination by the transportation safety board could take a year or more.