Anchored by Jake Tapper, The Lead airs at 4 p.m. ET on CNN.
Continuing coverage of Malaysia Airlines Flight 17. Plus, the latest on Mideast tensions.
(CNN) – Air traffic controllers assumed that Malaysia Airlines Flight 370 had turned back from Malaysia because of mechanical trouble, according to Reuters.
If that is true, they did not follow proper protocol, and if they had, "we wouldn't even be talking about this today," says CNN aviation analyst and pilot Miles O'Brien discuss.
"There was a narrow window there to stop this whole thing from happening," said O'Brien.
For more analysis from O'Brien, alongside former Navy oceanographer Van Gurley, and CNN safety analyst and author of "Why Planes Crash" David Soucie, click on the video above.