Huh. Why wouldn't the US show proof of this? Seems pretty easy to do.
From the page:
> According to the Iranian government, the cruiser negligently shot down the aircraft, which was transmitting IFF squawks in Mode III, a signal that identified it as a civilian aircraft, and not Mode II as used by Iranian military aircraft.
Given the US response (diplomatic note from Reagan), it seems that the error was on the USS Vincennes, not the Iranians.
From the page: > According to the Iranian government, the cruiser negligently shot down the aircraft, which was transmitting IFF squawks in Mode III, a signal that identified it as a civilian aircraft, and not Mode II as used by Iranian military aircraft.
Given the US response (diplomatic note from Reagan), it seems that the error was on the USS Vincennes, not the Iranians.