El Al Flight 402 was an international passenger flight from London to Tel Aviv via Vienna and Istanbul. On 27 July 1955, the flight, operated by a Lockheed Constellation registered as 4X-AKC, strayed into then-Communist Bulgarian airspace and was attacked by two Bulgarian MiG-15 jet fighters, crashing near Petrich. All 7 crew and 51 passengers on board the airliner were killed. The crash took place amid highly strained relations between the Eastern Bloc and the Western Bloc and was the deadliest involving the Constellation up to that time.