History of the Flight
The flight, MYT6286, was scheduled to depart from Harstad/Narvik Airport Evenes (ENEV) at 2100 local time on 25 November 2004, for a return trip to Norwich, UK. The crew arrived at the airport one hour prior, after a 1-hour 15-minute journey from company-provided accommodation. Upon arrival, flight plan and briefing documents were not immediately available, so the crew proceeded to the aircraft for pre-flight preparation. There had been light snowfall during the day, and very light snow was falling at the time. The crew obtained airfield operating conditions from the Automated Terminal Information Service (ATIS), which included a note of "8 mm dry snow."
The minimum braking action required for take-off, as per company Standard Operating Procedures (SOP), was "MEDIUM" in all three sectors of the runway. The braking coefficients from the ATIS were checked against the FCOM and MyTravel UK OM Part A, and both pilots agreed that a braking coefficient of 0.29 or greater was required; 0.30 and greater satisfied the minimum "MEDIUM" requirement.
After pushback to the de-icing area, the aircraft was de-iced with a one-step procedure using Type II fluid. At 2207 hours, a new friction measurement was performed and reported as 35/26/24 for runway 35, with 0 to 6 mm of dry snow. MyTravel Airways flight MYT6286 was informed of these numbers and indicated a requirement of minimum friction number 29. Airport personnel then initiated additional sanding of the runway north of taxiway D. The crew was assured that the friction numbers would improve to around 30 for the northern part.
Asymmetric Thrust and Runway Excursion
The aircraft was taxied by the First Officer for departure on runway 35. During the application of take-off power, an asymmetric build-up of engine thrust occurred, causing the left engine to lag the right engine. This resulted in a yawing moment that led to a loss of directional control. The aircraft yawed approximately 40° and departed the partially snow-covered runway, despite the crew selecting engine idle, applying nose wheel steering, and braking. The aircraft continued forward at a slow speed off the paved area onto an area of snow-covered soft ground. The nose wheel created a large furrow as the aircraft came to a stop in snow and soil at an angle of approximately 40° to the runway centre line. The tail and nose were 12 m and 35 m from the runway edge, respectively; the distance from the runway centre line to the edge was 22.5 m.
Damage and Conditions
Damage to the aircraft was limited to a punctured left nose wheel tyre, a separated and deformed left nose wheel hubcap, and a broken nose leg taxi light. The last reported friction numbers for runway 17 were 30-32-32 measured with a Skiddometer with high-pressure tire (BV-11/SKH). The runway was covered with up to 8 mm of loose dry snow upon sanded ice.
The lagging engine rpm of the left engine was probably caused by icing on the fan blades during the taxiing and holding before take-off.
No injuries to persons were reported, and no other damage was noted.