Russian investigators believe inadequate use of braking capabilities resulted in the overrun of a Nordavia Boeing 737-500 at Murmansk.

Investigators found that the aircraft overran the runway by 73m, according to the Arkhangelsk regional division of Russia's federal air transport regulator.

It states that the aircraft (VP-BQI), arriving from Moscow Domodedovo last 7 December, conducted a stable approach to runway 31 with flaps at 30°.

The coefficient of friction for the runway had been given as 0.42.

Cockpit-voice recorder information indicates the autobrake had been set to position '3', the inquiry says, less than the maximum. It adds that it has no fully-conclusive data confirming this setting.

The aircraft landed slightly beyond the touchdown zone, according to analysis by Murmansk airport's operator, at a speed of 135kt.

Reverse-thrust was activated some 800m from the threshold. The inquiry says this thrust was "close" to maximum, but not fully so. The aircraft was still travelling at around 100-110kt as it passed taxiway C, about 1,400m along the 2,500m runway.

Nordavia calculations suggested that, with the aircraft's configuration, the reverse-thrust setting would have increased the landing roll by 55m.

As the 737 slowed to 70kt the captain reduced the reverse-thrust setting but noticed "insufficient deceleration" and reverted to maximum reverse, using manual braking to assist.

This was not enough, however, to prevent the aircraft's overrunning the runway end. None of the passengers or crew members was injured.

Investigators attribute the incident to a "combination of factors", including the failure to apply maximum reverse over the first half of the runway.

Source: Cirium Dashboard