An in-flight breakup of the helicopter’s rotor system, following a collision of two blades, caused a fatal Kaman K-1200 crash in British Columbia in 2021, an investigation by Canada’s Transportation Safety Board (TSB) has found.
The incident took place Oct. 4, 2021, during a logging operation in Jervis Inlet, in B.C.’s lower mainland. It fatally injured Gary Weber, who at the time was chief pilot at Black Tusk Helicopter Inc.
Investigators said a blade on the K-1200’s left rotor collided with a blade on the right rotor.
The aircraft’s twin main rotor blades are out of phase by 90 degrees and tilted outward by 12.5 degrees from the vertical axis to allow each blade to clear the opposing rotor hub, per the TSB investigation report.
Investigators said the blade contact sequence started with a fracture of the bond joint between the servo flap’s inboard closeout and afterbody on a left rotor blade.
“The fracture likely initiated a fatigue crack in the servo flap skin that progressed until the afterbody separated in flight,” investigators said.
“This separation caused sudden vibrations in the left rotor system, the flutter of the three other rotor blades, and the failure of the left pylon structure that allowed for the blade contact.”
The aircraft entered a rapid descent shortly after dropping off a load of logs in an ocean pen. It turned around and initiated a climb to pick up another load but then began to fall, impacted the water within the log pen and sank, per the TSB report.
The company had been in regular radio contact with Weber and initiated an immediate search of the occurrence area, then called emergency services, the TSB found.
During the search, portions of all four main rotor blades were recovered. A search team found the helicopter eight days later using sonar.
The TSB issued an air safety advisory letter to Transport Canada (TC) following the incident, indicating the need for further examination of servo flap fractures on K-1200 helicopters.
In 2023, the U.S. National Transportation Safety Board (NTSB) determined that a servo flap failure caused a fatal K-1200 crash during firefighting operations in Pine Grove, Oregon, claiming the life of pilot Tom Duffy in August 2020.
“In response, TC stated that it was satisfied with the current manufacturer instructions for continued airworthiness, and that the United States Federal Aviation Administration is responsible for the airworthiness of these helicopters,” said the TSB.
“Kaman Aerospace Corporation, the manufacturer, has since performed various tests on the servo flaps and plans to continue testing.”
Weber, 60, was also an active farmer who logged almost 24,000 flight hours in a career that began in 1986, according to an obituary published in the Salmon Arm Observer.
He joined Black Tusk in 2007 and worked his way up to chief pilot, and also flew for several other operators over the years.
Weber is remembered as a man of “many private charitable acts and kindnesses for which he expected no recognition.”
