Czech investigators have determined that a Boeing 737-800 crew's failure to comply with sterile cockpit procedures during an approach to a wet runway contributed to its landing long and overrunning onto rough ground.
The US-registered Swift Air aircraft had been operating from Heraklion to Pardubice on 1 August last year.
Cockpit-voice recordings captured a "lively discussion" between the pilots on topics "not directly related to the flight performance" for the "whole time of approach and landing", says Czech investigation authority UZPLN.
The aircraft overflew the threshold of runway 27 at a height of 64ft and touched down at 965m (3,166ft) – almost 40% along the 2,500m runway – after a prolonged flare.
UZPLN says the crew "did not perform" a landing calculation in spite of acknowledging the wet runway status from approach control and the tower.
The selection of 30° flap and the 'autobrake 2' setting was "most likely only by guess and prior experience" with landing at Pardubice, it adds.
While the first officer, who was flying, queried whether to use a higher autobrake setting, the captain responded that this would not matter because reverse-thrust would be available.
The crew did not take into consideration tailwind information reported by air traffic control, says the inquiry, and a factored calculation should have warned the pilots that the true stopping distance could be longer than the landing distance available.
UZPLN adds that the crew also "failed to determine the go-around point".
The jet touched down with a groundspeed of 152kt and the pilots immediately applied reverse thrust.
As the aircraft decelerated through 80kt the captain took control of the aircraft – the investigators say that this was done "indifferently" – and commenced manual braking. Only after the aircraft had reached this 80kt threshold did the crew observe visual markings indicating it was approaching the runway end.
"It was this 'pace' of [the captain's] decision-making which, together with all the previous mistakes, was the last error which resulted in [the captain's] failure to brake [the] aircraft home on [the runway] after taking control," says the inquiry.
The aircraft overran onto grass and stopped with its main landing-gear about 12m beyond the end of the runway.
UZPLN says the distraction resulting from non-compliance with sterile-cockpit procedures meant the crew lost situational awareness.
"Both the pilots stopped being 'inside the flight' and were relying only on a routine approach and superficial assessment of risks," it states.
In testimony to the inquiry the captain and the first officer each underestimated the touchdown point. The captain had also believed the runway was wet, owing to reflective glare, and that the aircraft aquaplaned.
But investigation says the runway had only a low level of water contamination and suggests: "It is possible that, in fact, no aquaplaning was experienced."
None of the 159 passengers and six crew members was injured, and the aircraft (N624XA) – which was operating on behalf of Smartwings – was undamaged.