American Airlines Flight 444 was a scheduled American Airlines flight from Chicago to Washington, D.C.'s National Airport. On November 15, 1979, the Boeing 727 serving the flight was attacked by "the Unabomber", Ted Kaczynski, who sent the bomb in the mail and set it to detonate at a certain altitude. The bomb partially detonated in the cargo hold and caused "a sucking explosion and a loss of pressure," which was then followed by large quantities of smoke filling the passenger cabin, forcing the pilots to make an emergency landing at Dulles International Airport. Twelve passengers had to be treated afterward for smoke inhalation.