Rescue workers on Wednesday combed through the wreckage of Kyiv-bound Ukraine International Airlines Flight 752.
What brought down the plane isn’t yet certain, but some aviation safety experts and pilots called several aspects of the incident unusual. Because the crash occurred during heightened tensions between Iran and the U.S. information about the flight may remain scarce.
All 176 people — 167 passengers and nine crew — on the Boeing 737-800 were killed when it crashed two minutes after takeoff from Tehran. Video shared on social media showed what appeared to be the plane on fire, falling to the ground in a fireball outside of the Iranian capital.
The plane was not the 737 Max model that was grounded in March last year after two fatal crashes, but it adds to attention on Boeing, which is scrambling to contain the fallout from those incidents.
The crash occurred hours after Iran launched retaliatory missile strikes on U.S. positions in Iraq for the killing of Gen. Qasem Soleimani, timing that prompted speculation that a stray Iranian missile may have downed the passenger plane. But as of Wednesday evening, there was no evidence to support that. Airlines began avoiding airspace in the region, taking other routes due to the conflict.
It can sometimes take investigators more than a year to determine the cause of a plane crash and getting information about the deadly incident has become more complicated. Iranian officials said they won’t hand over a recovered black box from the crash site to the U.S. or to Boeing for review.