Horizon Airlines turboprop stolen at Sea-Tac Airport apparently crashes in Pierce County by KOMO Staff Friday, August 10th 2018 SEATAC AIRPORT, Wash. - Sea-Tac Airport was put on ground stop Friday night due to a security scare, according to Alaska Airlines. A source at JBLM said it involves a stolen plane, which two F-15's have been tasked to intercept and forced to land. The source says the military jet made contact with the stolen plane, which then began to nose dive and crashed in North Pierce County. Alaska Airlines said via Twitter they are aware of an incident involving an unauthorized take-off of a Horizon Air Q400. They believe there are no passengers on board. The Pierce County Sheriff's office said it was an airline mechanic stole the plane and was apparently doing stunts in the air then crashed into Ketron Island. Sea-Tac Airport officials said an airline employee conducted an unauthorized takeoff without passengers and the aircraft has crashed in south Puget Sound. They said normal operations at Sea-Tac Airport have resumed. Alaska Airlines tweeted that the plane involved is a Horizon Air Bombardier Q400 turboprop. The Alaska Airlines web page on that plane says it is 107 feet long with a wingspan of 93 feet 3 inches and a cruising altitude of 25,000 feet. It normally contains 76 seats. The Q400 has a cruising speed of 414 miles per hour and a crew of 2 pilots and two flight attendants.