Ukrainian investigators have determined that the autothrottle of a Belavia Boeing 737-300 was left active before the aircraft touched down long and overran at Kiev Zhulhany.
The jet had been operating from Minsk on 12 July last year, and had been descending in darkness and rain to Kiev’s downtown airport.
Ukrainian investigation authority NBAAI says that, during the descent, the runway in use was changed from 08 to 26.
As the aircraft passed through 500ft – at a distance of about 2km from the airport – the autopilot was disengaged and the crew continued manually with the autothrottle still active.
The crew was informed about the condition of the runway, being told that it was wet, with good braking and a friction coefficient of 0.52. Maximum autobrake was set.
Examination of the aircraft’s profile shows it crossed the displaced threshold at 36ft and 141kt, but that the flare lasted 14.5s. The jet only touched down 970m beyond the threshold, and the inquiry says the autothrottle’s engagement was a “major factor” contributing to the long landing.
Full reverse-thrust and maximum automatic braking was applied 4s after the landing. But the crew also applied manual braking after sensing that the jet was not decelerating fast enough.
The crew disengaged reverse-thrust at 61kt and the inquiry says the jet then received an “additional impulse” of direct thrust which prevented the crew was stopping within the runway length.
Analysis of the incident shows the aircraft experienced hydroplaning and tyre overheating, further contributing to the overrun.
While the coefficient of friction of the runway, measured after the event, was lower than the figure given to the crew, the inquiry says the aircraft should still have been able to stop in time, adding that reverse-thrust should have remained engaged until the 737 had slowed sufficiently.
Only minor damage to the aircraft (EW-336PA) resulted from the overrun. The inquiry says the crew experienced “high emotional and physical exertion” which, it states, led to incorrect decision-making.