Cessna 310I Crash in Calgary Due to Icing and Fuel Exhaustion

Flight Details and Accident Sequence On an instrument flight rules flight, a Cessna 310I (registration C-GWWO, serial number 310I0161) departed Manning for Calgary, Alberta, with Lethbridge as the alternate airport. During the initial descent into the Calgary area, the aircraft encountered light rime icing. While on radar vectors for an instrument landing system (ILS) approach to runway 34, the aircraft entered moderate icing conditions. The first approach was unsuccessful, and the pilot was vectored for a second approach. During the second approach, the aircraft descended into a rail yard 4.5 statute miles short of the runway at 1910 mountain daylight time. The aircraft collided with a structure on the roof of a diesel locomotive maintenance building and came to rest inverted. The pilot and two passengers evacuated unassisted; the pilot sustained serious injuries, while the passengers sustained minor injuries. ## Pilot Qualifications and Aircraft Condition The pilot was certified and qualified for the flight, with 2,200 total hours and 615 hours on Cessna 310s. The aircraft was not certified for flight into known icing conditions. Examination of the wreckage revealed no airframe failure or system malfunction prior to or during the flight. Both engines showed no indication of malfunction. The right propeller detached during impact, while the left propeller remained attached. Damage to the propellers indicated the right engine was turning but not producing power at impact, while the left engine was producing power. ## Weather and Icing Conditions A cold front was bisecting Alberta through the Edmonton area at 1200, with moderate icing forecast between 5,000 and 14,000 feet above sea level. Pilot reports indicated moderate rime icing and light freezing rain in the area. At 1900, weather at Calgary International Airport included winds of 030 degrees at 21 knots gusting to 26 knots, a ceiling of 500 feet broken, and a temperature of 1 degree Celsius. The pilot departed despite the aircraft not being certified for flight into known icing conditions, basing the decision on the low catch rate of ice and the absence of icing reports from other pilots. ## Fuel and Engine Power Loss The aircraft departed Manning with approximately 485 pounds of fuel, below the 564 pounds required for IFR flight to Calgary with Lethbridge as an alternate. The gas combustion heater used fuel from the right main tank at approximately three pounds per hour for most of the four-and-a-half-hour return trip. Auxiliary fuel gauges read empty en route, and main tank gauges read close to empty towards the end of the flight. The right auxiliary tank was the only fuel tank that did not rupture and contained a small quantity of fuel. The low fuel quantity, combined with lateral movement of the aircraft, likely caused the right main fuel tank port to become exposed to air, resulting in power loss on the right engine. ## Seat Installation and Injuries All occupied passenger seats broke free from the aircraft. The passenger seats were secured by lap belts attached to the seats, not the airframe. The seat rails were installed on top of carpet and foam underlay that had not been cut out around the attachment points, as required by the Cessna 310 Maintenance Manual. This incorrect installation prevented the seat rails from mating directly with the cabin floor structure, and the elasticity of the carpet and underlay contributed to the detachment of the seats. The pilot's seat was equipped with a lap belt and adjustable shoulder harness affixed to the aircraft structure. The pilot flew with the shoulder strap loosened to allow better movement, which resulted in serious head injuries to the right side of the face when his head hit the glare shield.