​Investigation of US regional carrier PenAir's Saab 2000 overrun in Alaska has turned into a fatal accident inquiry after a passenger succumbed to critical injuries.

Investigation of US regional carrier PenAir's Saab 2000 overrun in Alaska has turned into a fatal accident inquiry after a passenger succumbed to critical injuries.

The US National Transportation Safety Board has sent a team of nine to probe the landing accident involving flight 3296 from Anchorage to Unalaska airport on 17 October.

Two passengers were critically injured in the accident, during which the turboprop came to rest some 150m off the far end of Unalaska's runway 13, perched on a shoreline embankment and almost in the water.

Ten others received medical attention. Thirty-nine passengers and three crew members had been on board.

PenAir president and chief operating officer Brian Whilden has confirmed one fatality, after a passenger succumbed to injuries sustained in the overrun.

"Our entire team is devastated by this tragic incident," says RavnAir Group president Dave Pflieger. RavnAir is the parent of PenAir.

A preliminary US FAA notification identifies the airframe as N686PA and states that the aircraft "landed and exited [the] runway" and came to rest "with nose in harbour water".

Investigators have yet to confirm runway and weather conditions at the time of the accident, and the type of approach being conducted.

Fleets data from Cirium lists the Saab 2000 involved as a 24-year-old aircraft originally delivered to Air Marshall Islands, and operated by various carriers before its transfer to PenAir in mid-2017.