The Labour government then faced fresh public unease about the direction of the country and a damaging series of strikes during the winter of 1978–79, dubbed the "Winter of Discontent". The Conservatives attacked the Labour government's unemployment record, using advertising with the slogan "Labour Isn't Working". A general election was called after the Callaghan ministry lost a motion of no confidence in early 1979. The Conservatives won a 44-seat majority in the House of Commons and Thatcher became the first female British prime minister.
The Revolutionary Guard, or Pasdaran-e Enqelab, was established by Khomeini on 5 May 1979, as a counterweight both to the armed groups of the left, and to the Shah's military. The guard eventually grew into "a full-scale" military force,becoming "the strongest institution of the revolution."
American Airlines Flight 191, a McDonnell Douglas DC-10-10, crashed on May 25, 1979, shortly after lifting off the runway at Chicago O'Hare Airport after the number one (left) engine and pylon separated from the wing. This broke hydraulic lines, causing leading edge lift devices to retract on that side of the aircraft and resulted in an asymmetrical lift and loss of control. The accident was attributed to improper maintenance procedures. The crash resulted in the deaths of all 271 passengers and crew on board, as well as two people on the ground. It remains the deadliest commercial aircraft accident in United States history