On an unspecified date in 1985, a flight of unidentified aircraft entered the airspace surrounding Crescens Island, a Belkan territory at the time. Belka sent the Silber Team to respond. Silber proceeded to shoot down the unidentified aircraft.
The Wellow Incident was not officially named in English until Aces At War: A History 2019. Until then, Acepedia used a best guess to deduce the name "Wellow Incident".
The kanji ヴェレ (ヴェーレ without ー) translates to welle, the German word for "wave". Therefore, the best guess was "Wellow", the name of the country directly north of Crescens Island. Wellow's ties to this incident remain unknown.