The Iran Plane Crash Could Be the Latest in a Long History of Accidental Shoot-Downs

A Ukrainian International Airlines flight that crashed in Iran Wednesday, killing all 176 people on board, was likely shot down by Iranian forces, U.S. intelligence suggests.

While the crash of Flight 752 is a tragedy, the likely cause of the crash might not be entirely surprising, given the flurry of threats and tit-for-tat attacks exchanged between the Untied States and Iran over the last week. While civilian air travel is considered to be very safe, there is a long history of civilian aircraft being accidentally shot down in times of conflict.

“I don’t think it’s all that unusual,” Arnold Barnett, an aviation safety expert and a Professor of Statistics at the MIT Sloan School of Management, tells TIME. “I think given that war so often involves aerial fighting these days, you could argue that planes should be careful.”

In fact, both Ukraine and Iran have their own tragic histories of civilian aircraft being shot down during geopolitical conflicts. In July 2014, 298 people were killed when Malaysian Airlines Flight 17 was shot down in Ukraine’s Donetsk region by Russian separatists. In 1988, 290 people were killed when a U.S. ship shot down Iran Air Flight 655.

Barnett argues that airlines should err on the side of caution when considering the threat of sending flights through conflict zones — and urges civilian passengers to pay attention to warnings from the U.S. State Department and elsewhere.

“Planes being shot down accidentally—this is not something that’s never happened. And especially in wartime situations where you think it might happen, of course I think people should be thinking about it,” Barnett says.