Occurrence
A Fokker F-28 MK 1000, registration C-GKCR, serial number 11101, operated by Canadian Regional Airlines as flight 8604, was on a scheduled night passenger flight from Toronto, Ontario, to Fredericton, New Brunswick. On board were 42 passengers and four crew members. After landing on runway 09 at Fredericton Airport, the aircraft overran the end of the runway. There were no injuries to passengers or crew, and no damage to the aircraft.
Flight and Weather
The en route flight was uneventful. At 0122 Atlantic standard time, the crew advised the Fredericton Flight Service Station (FSS) that they were 18 minutes from the airport and requested current weather. The FSS specialist reported visibility as low as 4 statute miles in snow, winds from 020° magnetic at 7 knots, and temperature 0.4°C. The FSS also reported that sweepers were clearing a thin layer of slush from runway 15/33, but the official runway surface condition (RSC) was 100% bare and wet. The crew requested runway 09 be swept; vehicles began sweeping at 0125.
At 0134, the flight was cleared for a straight-in approach to runway 09 with the option to circle for landing on runway 33. At 0135, the FSS passed an RSC report for runway 09: on a 100-foot centreline, 50% bare and wet and 50% thin slush with ¼ inch of slush on the sides. The crew acknowledged and requested snow removal vehicles clear all runways. At 0137, an updated RSC report for runway 15/33 indicated it was 100% covered in wet snow and, on a 100-foot centreline, 1½ inches of slush. The crew were not informed that slush was accumulating rapidly on both runways. At 0138, visibility was reported as 2 to 3 statute miles; just before touchdown, winds were relayed as 010° at 7 knots.
Landing and Overrun
The aircraft flew a straight-in VOR approach using flap 42 and a Vref of 117 knots indicated airspeed. Speed brakes were selected at approximately 100 feet above ground level. At 0144, the aircraft touched down at 118 knots indicated airspeed, about 1400 feet beyond the threshold of runway 09, within the touchdown zone. Lift dumpers auto-deployed, and the captain manually activated them. Brakes were applied about one second after nosewheel touchdown. The crew sensed poor braking action but noted the anti-skid system cycling. The aircraft overran the runway end at 58 knots and came to rest about 320 feet beyond the end, near the perimeter fence. The crew shut down engines and started the auxiliary power unit. Two airfield firefighting vehicles responded; first arrived about 1½ minutes after alarm.
Post-Occurrence Findings
Fifteen minutes after the occurrence, an RSC report on runway 09 showed most of the runway covered in ¼ inch of slush, with the departure end 50% wet and 50% ¼ inch slush. The cockpit voice recorder overwrote occurrence information; the flight data recorder provided useful data indicating a routine flight and normal touchdown parameters. Stopping performance was significantly below that on a standard wet runway. No mechanical discrepancies were found. Aircraft loading was within limits; tires were in good condition. Intermittent tire skidmarks were found slightly left of centreline starting about 150 feet before the runway end. Brake systems functioned normally in post-occurrence tests.
The Canadian Runway Friction Index (CRFI) Recommended Landing Distances table was available, but CRFI measurements are not taken for slush-covered runways. The crew had no means of estimating a CRFI equivalence for slush. The RSC report did not indicate that slush was accumulating rapidly.
Causes and Contributing Factors
Slush reduced the stopping performance of the aircraft, and the aircraft was not able to stop in the runway length available. The crew was advised that the landing surface was 50% thin slush and 50% bare and wet, but their decision to land was based on bare and wet runway conditions. The crew was not advised that slush was accumulating rapidly on the runway surface during the approach. The Canadian runway friction index equivalence chart does not indicate a value for runways contaminated with slush. Runway surface condition reports do not indicate if a contaminant is accumulating or the rate of such accumulation.