The downing of a Black Tusk Helicopter’s Kaman K-1200 helicopter into Jervis Inlet, north of Egmont, on Oct. 4, 2021 was the result of an in-flight rotor system breakup, according to an investigation by the Transportation Safety Board (TSB) of Canada.
“A blade on the left rotor collided with a blade on the right rotor,” a TSB release dated Oct. 30 states.
“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.”
According to the release, the pilot and lone occupant of the helicopter was fatally injured in the crash. The name of the pilot was not released.
Investigation results
The TSB described that the incident occurred while the aircraft was conducting logging operations. After a load of logs had been dropped into an ocean pen, the pilot turned the helicopter and initiated a climb to pick up another load. Soon after, the helicopter entered a rapid descent, impacted the water within the log pen and sank.
The company, which had been in regular radio contact with the pilot, initiated an immediate search of the area and then called emergency services. During the search and rescue operation, portions of all four main rotor blades were recovered. Eight days later, the helicopter was located using sonar. An earlier report noted it was found 150 metres west of the initial collision site, at a depth of approximately 110 metres.
A posting on the TSB’s website detailed that, “The occurrence helicopter was not equipped with a flight data recorder or a cockpit voice recorder, nor was either required by regulation. Although the availability of other sources of data provided significant information for this investigation, the helicopter’s exact manoeuvring during the final moments and the time elapsed between the final data point and the actual impact with the surface could not be determined."
Follow-up actions
The release cited that, “Following the occurrence, the TSB issued an Air Safety Advisory Letter to Transport Canada (TC) informing them of the need for further examination of servo flap fractures on Kaman K-1200 helicopters. In response, TC stated that it was satisfied with the current manufacturer instructions for continued airworthiness. Kaman Aerospace Corporation, the manufacturer, has since performed various tests on the servo flaps and plans to continue testing.”
With files from Keili Bartlett
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