PC-12 Landed on Sea Ice after May 2024 Engine Failure

A Pilatus PC-12 made a successful landing on sea ice near Rankin Inlet, Nunavut, on May 7, 2024, after suffering an in-flight engine failure. Investigators later found midspan power turbine blade fractures, according to a Transportation Safety Board of Canada (TSB) report, but “the cause of the power turbine blades fracture could not be established.” All three occupants were uninjured.

The airplane landed upright and intact on snow-covered sea ice. Several fairings were cracked or broken, and the lower fuselage and trailing-edge flaps sustained abrasion damage. TSB investigators found the most significant structural damage at the bottom aft fuselage, where a navcom antenna had broken loose and “tore open approximately 0.5 sq ft of the fuselage.” Two of the four propeller blades were bent from contact with snow and ice. There was no fire nor any oil or fuel leakage.

Initial inspection revealed that both power turbine stages had suffered catastrophic midspan blade fractures. The TSB reported that “all the blades had experienced midspan fractures,” with most fragments exiting through the exhaust ducts. While the exhaust ducts and turbine vane ring were “heavily dented,” the fragments did not damage the fuselage or windscreen.

According to the TSB, the compressor section and combustion chamber showed no abnormalities, and the compressor turbine displayed only “a small piece of material missing” from a single blade.

The PC-12 was en route on one of a series of northern flights for Kudlik Aviation when the engine failure occurred. During a flight from Gjoa Haven to Taloyoak the previous day, the crew heard “an unusual bang.” Troubleshooting produced no anomalies, and the noise could not be reproduced. The report notes that it “was possibly caused by a momentary bleed-off valve fault.”

On the morning of May 7, the crew departed Taloyoak for flights to Naujaat and Chesterfield Inlet, with both legs uneventful. Operating as flight KUK761, the aircraft departed Chesterfield Inlet for Rankin Inlet at 9:37 a.m. under IFR with two pilots and one passenger aboard.

According to the TSB, the PC-12 “performed normally until the power was reduced for descent.” Shortly after descending through 4,000 feet agl, “the engine emitted a series of bangs with flames appearing from the exhaust ducts followed by a sharp reduction in power.” Attempts to restore thrust were unsuccessful, and the crew declared a mayday to Rankin Radio.

At 9:51 a.m., the aircraft touched down on the sea ice approximately 5 nm east of Rankin Inlet Airport with the landing gear retracted. The emergency locator transmitter failed to activate automatically, and the crew manually switched it on. Local emergency personnel arrived about an hour and 20 minutes later by snowmobile. There were no injuries, and the TSB noted that cargo restraints were in use and occupants evacuated through the main cabin door.

The aircraft’s Pratt & Whitney Canada PT6A-67B- engine logged 13,498.6 hours and 8,694 cycles since new. It was overhauled in 2020 in accordance with the manufacturer’s specifications, and all ADs and service bulletins were up to date. At the time of the accident, the engine was operating under a Transport Canada-approved extension to a 5,000-hour overhaul interval.

Engine condition monitoring system data recovered by the TSB laboratory showed normal parameters before the failure. The aircraft was being operated “within the power settings recommended” for altitude, temperature, and configuration. After the engine failed, propeller speed did not decrease enough to indicate a feathered condition. Magnetic chip detector findings were consistent with a major internal failure. The front gearbox detector plug “was covered with metal contaminants.”

A full teardown at the manufacturer’s facility confirmed damage “consistent with midspan fractures of the power turbine blades,” along with overheating and galling on bearing surfaces in the reduction gearbox. Metallurgical analysis found that the blade material met specifications and showed “fracture by tensile overload,” but the cause for this is unknown.

Kudlik Aviation operates four aircraft under Canadian Aviation Regulations Subpart 703. The captain held an ATP licence with 15,300 hours TT, including 14,200 hours in type and approximately 13,000 as PIC. The first officer had 712 hours TT, 502 of them as PC-12 first officer. Both held valid medical certificates and ratings.

The aircraft’s weight and balance were within limits. A previous maintenance cycle had been completed at 13,701.2 airframe hours, and there were no outstanding defects.

“The correct use of safety belts and cargo restraints can improve survivability outcomes during forced landings,” the TSB noted.