CHEYENNE, Wyo. (AP) — The National Transportation Safety Board says a combination of mechanical failure and inadequate monitoring by the pilot likely caused an American Airlines passenger jet to go off the runway at Jackson Hole Airport.

The plane sustained minor damage but nobody was hurt among the 185 passengers and crew. The plane had just landed when it overshot the pavement and rolled into deep snow in December 2010.

The board determined Tuesday that the plane's thrust reversers did not engage. A defect then prevented automatic deployment of the plane's speed brakes.

Speed brakes are wing flaps that create air drag. The board determined that the pilot became too preoccupied with the thrust reversers and failed to deploy the speed brakes manually.

The Jackson Hole Airport is a notoriously challenging place to land.