Alitalia Flight 404 (AZ404/AZA404) was an international passenger flight scheduled to fly from Linate Airport in Milan, Italy, to Zürich Airport in Zürich, Switzerland, which crashed on 14 November 1990. The Douglas DC-9-32, operated by Alitalia, crashed into the woodlands of Weiach as it approached Zurich Airport, killing all 46 people on board.A Swiss investigation concluded that the crash was caused by a short circuit, which led to the failure of the aircraft's NAV receiver. The malfunction went unnoticed by the crew, who likely believed they were on the correct flight path until the crash. Swiss authorities also blamed inadequate crew resource management, exemplified when the captain vetoed the first officer's attempted go-around, along with the absence of lighting on Stadlerberg Mountain and a known problem with errors in reading the drum pointer altimeter of the aircraft.
The final report by the Federal Aircraft Accidents Inquiry Board requested several major changes and made further recommendations.