The deadly plane crash into Washington, D.C.’s Potomac River on Wednesday night has raised questions about aviation safety, even as federal agencies say the United States has some of the strictest airline regulations in the world. 

The Federal Aviation Administration’s website boasts that the U.S. has the world’s toughest qualifications for airline pilots. While most foreign countries are required to have only between 200 and 250 hours of experience, U.S. co-pilots are required to possess a minimum of 1,500 hours of flight experience under legislation passed by Congress in 2010.