1 fatality

2011-04-01: Casa 212 Aviocar (C-FDKM) — Fugro Airborne Surveys Canada — Saskatoon, Canada

Saskatoon, CanadaLanding (descent or approach)

On April 1, 2011, a Casa 212 Aviocar (registration C-FDKM) operated by Fugro Airborne Surveys Canada was involved in an aviation accident near Saskatoon, Canada during landing or approach. One person was killed. Investigators recorded the probable cause as: Findings as to Causes and Contributing Factors: 1. The right engine lost power when the intermediate spur gear on the torque sensor shaft failed. This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A).

Sourcesthe Bureau of Aircraft Accidents Archives (B3A)Primary reportUpdated 1781195549Data APIEditorial standards

A CASA C-212 CC40 experienced right engine failure followed by left engine flameout during approach, leading to a forced landing and impact with a noise abatement wall. The survey operator sustained fatal injuries.

Accident Overview

At 1503 Central Standard Time, a Construcciones Aeronauticas SA (CASA) C-212-CC40, registration C-FDKM (serial number 196), operated by Fugro Aviation Canada Ltd., departed from Saskatoon/Diefenbaker International Airport, Saskatchewan, under visual flight rules. The aircraft was conducting a geophysical survey flight to the east of Saskatoon, with two pilots and a survey equipment operator on board.

During the flight, at approximately 1814, the right engine lost power. The crew shut down the engine, performed the appropriate checklist procedures, and initiated an approach for Runway 27. While on final approach, approximately 3.5 nautical miles from the runway, the left engine lost power. The crew executed a forced landing adjacent to Wanuskewin Road in Saskatoon. The aircraft struck a concrete roadway noise abatement wall and was destroyed. The survey equipment operator sustained fatal injuries, the first officer sustained serious injuries, and the captain sustained minor injuries. No ELT signal was received.

Engine Power Loss and Contributing Factors

According to the official investigation, the right engine lost power because the intermediate spur gear on the torque sensor shaft failed, resulting in a loss of drive to the high-pressure engine-driven pump, leading to fuel starvation and immediate engine stoppage.

The left engine's No. 2 ejector pump's ability to deliver fuel to the collector tank was compromised by foreign object debris (FOD) in the ejector pump nozzle. As the fuel level in the left collector tank decreased, the left fuel level warning light likely illuminated but was not noticed by the crew. The pilots did not execute the fuel level warning checklist because they did not perceive the illumination of the warning light. Consequently, the fuel crossfeed valve remained closed, and fuel was supplied only from the left wing to the left engine. The left engine flamed out due to depletion of the collector tank and fuel starvation, leading to the forced landing and impact with the noise abatement wall.

Risk Findings

The investigation identified several risk factors. In single-engine uncoordinated flight, depending on fuel level and bank angle, the ejector pump system may not have the delivery capacity to prevent collector tank depletion when the No. 1 ejector inlet is exposed, especially with the engine at full power. The master caution annunciator does not flash, which could result in the crew not noticing an annunciator panel segment illumination and failing to take corrective action. The absence of cockpit voice and flight data recordings may preclude the identification and communication of safety deficiencies. Additionally, because the ejector pump inlets are unscreened, FOD in the fuel tank may become lodged in an ejector nozzle, reducing fuel delivery to the collector tank.

Other Findings

The crew's decision not to recover or jettison the birds immediately resulted in extended operation with minimal climb performance. The composition and origin of the FOD, as well as how or when it entered the fuel tank, could not be determined. The SkyTrac system provided timely position information that would have assisted search and rescue personnel if needed. Saskatoon police, firefighters, and paramedics responded rapidly and provided effective assistance to the survivors.

Probable cause

Findings as to Causes and Contributing Factors: 1. The right engine lost power when the intermediate spur gear on the torque sensor shaft failed. This resulted in loss of drive to the high-pressure engine-driven pump, fuel starvation, and immediate engine stoppage. 2. The ability of the left-hand No. 2 ejector pump to deliver fuel to the collector tank was compromised by foreign object debris (FOD) in the ejector pump nozzle. 3. When the fuel level in the left collector tank decreased, the left fuel level warning light likely illuminated but was not noticed by the crew. 4. The pilots did not execute the fuel level warning checklist because they did not perceive the illumination of the fuel level left tank warning light. Consequently, the fuel crossfeed valve remained closed and fuel from only the left wing was being supplied to the left engine. 5. The left engine flamed out as a result of depletion of the collector tank and fuel starvation, and the crew had to make a forced landing resulting in an impact with a concrete noise abatement wall.