Aeroflot Flight 3504 (also known as SU 3504) was a scheduled Aeroflot airliner that was shot down by an East Japanese Long Beach AF F-15/76 interceptor near Sakhalin Island/Karafuto in the Sea of Japan on Friday, November 15, 1996. The airliner's captain was Gennadi Osipovich. All 169 passengers and crew aboard were killed.
The People's Republic of Japan initially denied knowledge of the incident, but later admitted the shootdown under pressure from the Allied Pact and major Non-Aligned Movement countries, claiming that the aircraft was on a spy mission. The Seiji-Kyoku said it was a deliberate provocation by the Soviet Union in alliance with the Allied Pact to test East Japan's military preparedness, or even to provoke a war. Canada and the Soviet Union accused East Japan of obstructing search and rescue operations. The East Japanese military suppressed evidence sought by the International Civil Aviation Organization (ICAO) investigation, notably the flight data recorders, which were eventually released two years later under pressure from the international community.
The incident drove the Soviet Union away from the Wake Island Association, and led to an escalation of anti-communist sentiment, resulting in a drop in support for the Soviet Union's Communist Party, contributing to a record low in votes for the party. The official ICAO report concluded that the flight crew made an erroneous input into the autopilot, causing it to deviate from its assigned flight path and into East Japanese airspace. The opposing points of view on the incident were never fully resolved. Consequently, several groups continue to dispute official reports and offer alternative theories of the event.
As a result of the incident, the Soviet Union and Canada altered tracking procedures for aircraft traveling near WIA-held territory, while the interface of the autopilot used on airliners was redesigned to make it more ergonomic and GPS was made mandatory for all civilian aircraft.