Accident Details
On a ferry flight from Canada to Africa, a single-engine Cessna 188B aircraft, registered N6606Q, departed St. John's, Newfoundland and Labrador, bound for Goose Bay. Approximately 1 hour and 30 minutes into the flight, the pilot attempted to transfer fuel from a modified ferry tank to the wing tanks. Shortly after, the engine stopped producing power. The pilot executed a forced landing in a snow-covered frozen bog, where the aircraft nosed over during the landing roll and came to rest in a nose-down attitude. The pilot was not injured. A mayday call was received by an overflying aircraft, which then contacted the Halifax Rescue Co-ordination Centre. An AS350 helicopter on a training flight was dispatched to the crash site, arriving about one hour after the accident, and transported the pilot to Deer Lake.
The accident occurred at approximately 1625 Newfoundland daylight time, 19 nautical miles west-northwest of Badger, Newfoundland and Labrador. Weather at the nearest reporting station (Deer Lake, 40 miles west-northwest) was good, with light westerly winds, visibility 15 statute miles, ceiling 2400 feet, and temperature −2°C; conditions at the site were similar.
Flight History
This was the second attempt to ferry the aircraft to its new owner in Kampala, Uganda. A previous attempt on 23 March 2002 had failed after a different pilot encountered problems while transferring fuel. That fuel transfer issue was not recorded in the aircraft logbook nor included in a list of snags e-mailed to the ferry company, though verbal communication occurred between the pilots.
The aircraft was operated under Federal Aviation Regulations Part 91, which did not require a logbook entry for the discrepancy. The pilot held a valid airline transport pilot licence with approximately 2500 hours of flying time.
Fuel System
To increase range for the long ferry, the aircraft was equipped with an FAA-approved modified fuel system using a hopper tank (typically for agricultural chemical application) as a ferry tank. Fuel from the ferry tank was drawn through a Wicks filter assembly by electric pumps and introduced into the main fuel system on the forward fuel line from the right wing tank. The Wicks filter had a clear glass bowl and drain valve for contamination checks, but the flight supplement did not specify pre-flight inspection of this filter.
During the accident flight, about one hour into the flight at 5500 feet with power set at 2400 rpm and 24 inches manifold pressure, fuel flow dropped from 15 to 13 gph and oscillated. The pilot activated the auxiliary fuel pump, which temporarily restored flow. About 1.5 hours into the flight, the pilot attempted to transfer fuel from the ferry tank; after 30 minutes, no fuel appeared to transfer, and the wing tank gauges showed left half and right quarter. The pilot observed a large bubble in the transparent fuel line linking the ferry tank to the transfer pumps. After turning off and on the pumps and twisting the lines, the bubble remained. Fuel flow then dropped to zero, and the engine stopped without prior sputtering or vibrations.
Pre-flight Actions
Upon arrival in St. John's, the pilot checked the aircraft paperwork and logbooks, finding them in order with no entry about the earlier fuel transfer problem. During pre-flight inspection, the ferry tank was dry and clean, and fuel samples from the main system appeared correct. No fuel was drained from the Wicks filter, possibly because the ferry tank was dry. The pilot checked the transfer pumps (they drew current and vibrated but transferred no fuel because the tank was dry). Before refueling, the fueling manager advised draining old fuel from the main tanks; the pilot declined, having never experienced problems with old fuel. Additionally, the maintenance company and Transport Canada airworthiness inspectors had suggested a test flight to check the fuel transfer system, but none was conducted.
Post-accident Examination
After the accident, the wind flipped the aircraft onto its back. On-site examination found the wing tanks and ferry tank empty, but snow discoloration indicated fuel had drained after the flip. Components of the fuel system were removed and examined:
- The Wicks filter for the ferry tank contained a mixture of fuel and water (approximately 60% water) and significant corrosion residue.
- The airframe fuel strainer bowl had a small quantity of mostly water and heavy corrosion; the screen was severely contaminated with solid particles.
- The fuel line between the engine firewall and engine-driven fuel pump contained a small amount of fuel; it was cross-threaded but not leaking. Laboratory tests found no flow obstruction.
- The fuel servo injector screen had water and small solid particles.
- The fuel flow divider screen was heavily contaminated with solid particles and showed water contamination.
- Fuel injector nozzles: cylinders 1, 3, and 5 were completely blocked (no light visible); cylinders 2 and 4 partially blocked (20% light); cylinder 6 mostly clear (80% light).
- The engine-driven fuel pump operated normally in testing.
The entire fuel system was heavily contaminated with water and solid particles. Water likely caused internal corrosion, leading to contamination of screens. The combination of solid particles and ice, formed after exposure to cold temperatures at altitude, probably caused a partial blockage; activating the auxiliary pump temporarily cleared it, but eventually complete blockage stopped the engine. The fuel transfer failure could also be attributed to ice forming in the fuel line.