PRESQUE ISLE, Maine (AP) The National Transportation Safety Board is investigating why a United Express regional jet slid off a runway, injuring a pilot and four passengers.

The Presque Isle International Airport reopened Tuesday, but the 50-seat Embraer 145 remained where it came to a rest the day before. An official said the pilot aborted the first landing attempt during a snowstorm and requested that the runway lights be turned on.

The jet came to a rest in deep snow on the second landing attempt.

Part of the jet’s landing gear ripped away and ended up wedged in the cowling of one of the turbofan engines. The nose cone also was damaged.

The CommutAir-operated flight from Newark, New Jersey, had 28 passengers and three crew members. The injured were treated and released.