Event Summary
On October 11, 2019, at approximately 0902 Kenya daylight time, a Silverstone Air Services Fokker 27 Mark 050, registered as 5Y-IZO, was involved in a runway excursion during takeoff from runway 14 at Wilson Airport. The aircraft was operating a scheduled flight to Mombasa and Lamu, with a planned return to Wilson. There were 55 persons on board, including 5 crew members and 50 passengers.
Sequence of Events
The aircraft was fueled and passengers boarded prior to the commencement of normal pre-takeoff procedures, which were reported as uneventful according to flight data recorder (FDR) information. During engine start, the right-hand engine lagged behind the left-hand engine in start-up, as indicated by recorder parameters. The subsequent phases of engine start, taxi, lineup on runway 14, power application, and initial ground roll were also uneventful.
At 06:02:50 GMT, while still in the ground roll phase of takeoff, the left-hand engine's inter-turbine temperature (ITT) began to fluctuate, dropping from 707.8 to 175.8 degrees Celsius. The right-hand engine's ITT remained stable, and other parameters of both engines were stable. At 06:03:01 GMT, power was reduced, and the indicated airspeed dropped from 110.2 knots. The aircraft's magnetic heading gradually increased to 144 degrees, consistent with a deviation to the right of the runway axis. The aircraft left the paved surface of the runway, struck the airport perimeter fence, traversed an embankment, and came to rest tilted to the right after the starboard wing made contact with a tree.
Aftermath
Passengers were evacuated through the two left-hand side front and rear exit doors. The Wilson Airport Air Traffic Services issued a crash alert, and the Wilson Airport Fire Service responded promptly. Firefighters found that passengers had already evacuated and applied foam to sections of the aircraft where fuel was leaking. Runway 14/32 was closed, and all incoming and departing traffic utilized the remaining runway space.
Investigation
Preliminary information retrieved from the flight data recorder regarding the left-hand engine ITT correlated with flight crew statements about observed fluctuations in that engine. The investigation continued to examine the circumstances of the event.