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Carburetor icing possible factor in downed Island plane that sent pilot to hospital

TSB report released on 2022 emergency landing that put plane in ditch near Qualicum Beach airport
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(Parksville Fire Department photo)

The Transportation Safety Board of Canada (TSB) has released its investigation report on an emergency landing by a small aircraft near Qualicum Beach Airport last summer that sent the pilot to hospital.

The Cessna 172P crash landed in a treed area along the edge of a farmer’s field the evening of July 24, 2022. Its lone occupant and pilot, Akhilesh Shere, was transported by air ambulance to hospital with serious injuries.

The aircraft landed nose down on the sloped bank of a water-filled ditch, with its propeller embedded in the ditch. One blade was damaged significantly, while the other was not damaged at all — this is consistent with the engine producing low power or not operating on impact, the report said.

“Based on the conditions at the time of the occurrence, there was a potential for serious carburetor icing at descent power,” the report said. “Even though the investigation was unable to determine if carburetor icing was a factor in this occurrence, pilots are reminded that carburetor icing can occur even in warm temperatures.”

The Cessna 172P Pilot Operating Handbook states that carburetor ice may result in “[a] gradual loss of RPM and eventual engine roughness.” To prevent carburetor icing, the handbook includes the application of carburetor heat on various checklists.

“For the duration of the occurrence flight, the carburetor heat was in the OFF position,” the report said.

READ MORE: Pilot taken to hospital after emergency landing at Qualicum Beach Airport

Based on the weather conditions recorded closest to the time of the emergency landing, carburetor icing was charted as moderate icing during cruise power and serious icing during descent power, according to the report.

The investigation revealed that a pilot had reported a rough-running engine on the right magneto 52.9 air time hours before the incident. However, an aircraft maintenance engineer was unable to duplicate the fault during an engine run-up on the ground, and the aircraft was returned to service.

The aircraft departed CYYJ (Victoria International Airport) shortly before 7 p.m. and flew at cruising altitude for approximately 27 minutes. During his approach to CAT4 (Qualicum Beach Airport), the pilot conducted a reduced power descent, first to 2000 feet, then to 1300 feet, according to the report.

“Shortly after the aircraft had levelled off at 1300 feet, the pilot increased throttle and the engine began to sputter and its speed decreased from approximately 2300 rpm to 1200 rpm,” the report said. “The pilot further increased throttle, but the engine did not respond.”

The pilot initially manoeuvred in the direction of Runway 29, but opted to conduct an emergency landing on Runway 11 and announced his intention on the airport’s mandatory frequency. He initiated a left turn, reduced throttle, added full flaps, and entered a forward slip in a steep descent, the report said.

At 7:38 p.m., the aircraft briefly contacted the surface of Runway 11 beyond Taxiway C, at which point less than 1850 feet of runway remains, and became airborne again. The pilot initiated a go-around and increased the throttle to full power, raised the flaps, and the aircraft entered a climb. Seconds after the initial touchdown, the pilot initiated a steep right turn immediately before reaching tree-covered, down-sloping terrain, and the aircraft began a rapid descent in a right bank and nose-down attitude. The pilot declared a Mayday on the airport’s frequency.

First responders found the pilot secured with lap belt only and no shoulder harness, but the TSB investigation later determined the stitching of the shoulder harness webbing failed at the aft anchor bracket. As a result, the shoulder harness webbing pulled through the bracket during the impact. The aircraft’s safety belts were inspected 10 days before the occurrence, during the aircraft’s annual inspection, according to the report.

Canadian Aviation Regulations require that each part of the safety belt assembly be marked. The aircraft’s lap belts each had an attached label that included the rated strength of the belt, however, the shoulder harness did not have a label the report found.

The plane’s engine was removed and an examination found its overall condition “unremarkable,” the report found. The examination found two anomalies of note: the right magneto was firing intermittently below 1800 rpm. and the oil sump contained significant magnetic metal particles.

“It is unlikely that the intermittent firing of the magneto would have significantly degraded engine operation,” the report said. “The metal particles found in the oil sump could not be sourced to the failure or absence of an internal engine component. There were no signs that the particles caused secondary damage to the internal engine components or precluded the engine from operating.”

First responders noted that fuel was initially leaking from the right wing and TSB investigators recovered approximately 4.5 U.S. gallons of fuel that remained in the aircraft.

Because oil and fuel leaked from the aircraft, the area underwent an extensive environmental rehabilitation that included removal of contaminated water and soil, the report said.

The TSB report is intended for information purposes and is not meant to assign blame or fault for the incident.

— NEWS Staff

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