Occurrence
On an IFR night passenger flight from Toronto, Ontario, to Saint John, New Brunswick, Air Canada Regional Airlines Flight 8610 (TCN8610), a Fokker F-28 MK 1000 aircraft (C-FCRK), landed on Runway 05 at Saint John Airport at 0030 Atlantic standard time. After nosewheel touchdown, the aircraft drifted uncontrollably to the left. The left main wheels departed the runway for approximately 900 feet before re-entering the runway surface. The furthest point of excursion was 15 feet from the runway edge. Damage was limited to minor cuts in the tires of the right main gear and nosewheel. No injuries occurred.
Weather and Runway Conditions
Saint John Airport is an uncontrolled airport with two runways: Runway 05/23 (7000 feet long) and Runway 14/32 (5100 feet long), both 200 feet wide and asphalt surfaced. At 0006, the flight contacted the Saint John Flight Service Station (FSS) and received weather: visibility ¾ mile in light snow, ceiling 800 feet, winds 140° magnetic at 9 knots, temperature −2°C, dew point −5°C, altimeter 30.38. The airfield was snow covered; an RSC report was being prepared.
Snowfall began at 2308. Temperature had fluctuated around freezing; at 2300 it was 0.1°C. Prior to this, no precipitation for days, runways bare and dry. Snow removal personnel were recalled after snowfall commenced.
At 0012, the RSC for Runway 05/23 indicated 100% snow cover up to ¼ inch. The Canadian Runway Friction Index (CRFI) average was 0.52, equated with good friction characteristics. This report was relayed to the flight at 0020, about 10 minutes before landing. The crew declined a centreline sweep, which would have taken 11–13 minutes.
At 0022, Runway 14/32 was reported 100% snow covered to ¼ inch with a CRFI of 0.23. This was not passed to the crew, nor did they request an update.
Flight and Landing
The crew conducted an uneventful ILS approach with Vref 117 KIAS, using flap 42. Flight data recorder indicated touchdown near centreline at 0030, speed 114 KIAS, heading 054° (3° right of runway heading). Nosewheel touched at 106 KIAS about two seconds later. After nosewheel contact, heading increased to 065° while the aircraft drifted left. The drift was likely due to crosswind and a small pre-existing left drift, but the extent of each could not be established.
Crew used rudder and nosewheel steering but the aircraft continued leftward and off the runway, despite increased right heading. Left main wheels were off the runway for about 900 feet, slewed 15–20° right of runway heading. Partial control regained as left main wheels returned to runway. Steering remained ineffective; aircraft slid with nose slewed right. Left engine was shut down at about 60 KIAS, and the aircraft aligned with the runway, then stopped and taxied to the ramp. Crew reported very poor braking action.
Post-Occurrence
Ground personnel confirmed the excursion. Both runways were cleared; subsequent RSC indicated 1/8 inch slush contamination on the cleared centre 100-foot portion. CRFI for cleared portion of Runway 05/23 was 0.36; for Runway 14/32, 0.34. No significant tire skid marks were found.
After the flight, crew inspected for damage, consulted maintenance, and reinspected next morning. No apparent damage, and aircraft departed for revenue flights. Later, it was discovered that tires had struck a runway edge light, broken but not noticed due to snow cover. Small cuts—typical of gravel runways—were found on right main and nosewheel tires. They were replaced as a precaution. Braking and steering functioned normally.
Additional Information
Surface conditions greatly influence friction. Poor friction decreases stopping and steering performance. RSC/CRFI reports are snapshots; they do not indicate accumulation rate, melting, or freezing. Transport Canada's Aerodrome Safety Circular describes when reports are required. CRFI measurements are accurate only for packed snow or ice; not taken with slush. No CRFI equivalence for slush exists in the chart. The AIP Canada crosswind limits table recommends minimum CRFI of 0.3 for the crosswind (90° at 9 knots); the crew received 0.52, above this minimum. The ICAO Airport Services Manual emphasizes contaminant removal as priority.
Despite rudder and nosewheel steering inputs, drift continued, indicative of poor friction at landing. The crew relied on the CRFI reported 10 minutes before touchdown, not expecting significant change. However, melting snow may have turned to slush, reducing friction. The CRFI for Runway 05/23 was 0.52, but for Runway 14/32 it was 0.23, despite similar contamination—likely due to melting on Runway 05 after measurement.