Flight Background
At 2320 Newfoundland daylight time on 03 April 2001, a Royal Cargo flight, a Boeing 737-200, departed Mirabel, Quebec, on a scheduled instrument flight rules cargo flight with two pilots. The flight was routed to Hamilton, Ontario; Mirabel; Halifax, Nova Scotia; St. John's, Newfoundland; and Mirabel. The initial segments from Mirabel to Halifax proceeded without incident.
Weather and NOTAMs
Before departure from Halifax, the pilot flying (PF) received the latest weather for the St. John's leg from company dispatch but did not request or receive the latest NOTAMs. At 0545, the aircraft departed Halifax. After departure, the PF contacted Halifax Flight Service Station and received the 0530 METAR for St. John's: wind 050° magnetic at 35 knots gusting 40, visibility 1 statute mile in light snow and blowing snow, ceiling 400 feet overcast, temperature -1°C, dew point -2°C, altimeter 29.41 inches of mercury. The FSS also provided RSC reports for both runways, including CRFI readings of 0.25 for Runway 11/29 and 0.24 for Runway 16/34. Additionally, the FSS relayed NOTAMs for St. John's, including one issued over five hours earlier advising that the ILS for Runway 11 was unserviceable.
Crew Actions and Decision-Making
The crew initially planned an ILS approach to Runway 11. Due to marginal weather, the loss of Runway 11/29, and the training captain's greater experience, the training captain and PF switched seats, with the training captain assuming duties as captain and PF. Returning to Halifax was not considered because the aircraft would be overweight for landing there. The crew discussed diverting to the alternate but concluded a safe landing at St. John's was achievable.
At 0638:27, the PF contacted St. John's tower to inquire about Runway 34. The controller indicated that Runway 34 was likely the only option due to wind (050°M estimated at 35 gusting 40). The ILS on Runway 11 was unserviceable, and the glidepath for Runway 29 was unserviceable. Only the localizer back course Runway 34 and ILS Runway 16 approaches were available. Around 0638, Gander ACC suggested obtaining the 0630 ATIS, which reported surface winds of 055°M at 20 gusting 35, but the crew did not obtain it due to a simultaneous transmission. At 0641, Gander ACC reported St. John's winds as 040°M at 13 gusting 18. The PNF noted the discrepancy, but the PF did not acknowledge its significance. It was later determined that the anemometer at St. John's was unserviceable due to ice accretion, providing incorrect wind data to Gander ACC.
At 0644, Gander ACC transmitted a SIGMET issued at 0412, valid from 0415 to 0815, forecasting severe mechanical turbulence below 3000 feet due to surface wind gusts exceeding 50 knots. The crew may not have listened; they were discussing an 18-knot quartering tailwind for the Runway 16 approach. They did not acknowledge the SIGMET until prompted by the controller.
Before descent, the crew discussed approach options. Runway 11 was discounted due to unserviceable ILS; Runway 34 was below minimums. They decided to attempt the ILS to Runway 16 despite the PNF's tailwind concerns, as the Gander ACC wind data was within aircraft limits. In calculating approach speed, confusion arose in applying tailwind and gust corrections. The crew established a Vref of 132 KIAS for flap 30 and an approach speed of 142 KIAS, derived from the incorrect wind data. They added a 5-knot gust increment (Vref+10), consistent with company practice. During descent, they struggled to complete checklists.
Approach and Landing
Clearance for the ILS Runway 16 approach was obtained from Gander ACC, and the crew was advised to contact St. John's tower. Just over two minutes before landing, the tower reported wind 050°M estimated at 20 gusting 35 and provided an RSC for Runway 16: full length 170 feet wide, surface 30% very light dusting of snow and 70% compact snow and ice; remainder 20% light snow, 80% compact snow and ice; windrow along east side; friction index 0.20; temperature -1°C at 0925.
The aircraft crossed the final approach fix on the glideslope at 150 KIAS. During final approach, airspeed increased to 180 KIAS (ground speed 190 knots), with a descent rate of 1000 feet per minute. From 1000 feet above sea level, no airspeed calls were made; altitude calls were made and acknowledged. The Royal Boeing 737 operations manual requires the PNF to call significant airspeed deviations. At about 900 feet, turbulence caused uncommanded roll and pitch deviations and airspeed fluctuations of ±11 knots. Around 300 feet above decision height, the crew acquired visual references. Approximately one minute before landing, the tower transmitted runway visual range, repeated the estimated wind, and issued landing clearance, which the PNF acknowledged.
The aircraft touched down at 164 KIAS (27 KIAS above desired Vref), 2300 to 2500 feet beyond the threshold. Radar ground speed at touchdown was 180 knots. The wind was determined to be about 050°M at 30 knots. Shortly after touchdown, speed brakes and thrust reversers were deployed; an engine pressure ratio (EPR) of 1.7 was reached 10 seconds after touchdown. Longitudinal deceleration was -0.37g within 1.3 seconds, indicating effective wheel braking. With approximately 1100 feet of runway remaining, at 64 KIAS, reverse thrust increased to about 1.97 EPR on engine 1 and 2.15 EPR on engine 2. As the aircraft approached...