It's been two weeks since the Malaysia plane's disappearance, and the fate of MH370 remains a mystery.
Prime Minister Najib Razak said recently the jet went missing due to "deliberate action by someone on the plane." Investigators searched the pilot's home and found a homemade flight simulator with deleted data. But there's still no word on whether those deleted files are connected to the plane's disappearance, or if they'll offer any clues at all.
Of course, thousands of flights land safely every day in the U.S., but now the jet mystery is raising questions about how pilots get screened -- both in the U.S. and abroad.
Below, hear from Dr. Robert Noven, an aviation medical examiner at Northwestern Memorial Hospital, who explains why it can be tough to spot pilots with psychological problems during their FAA physical.
Learn more tonight on "Nightly News with Brian Williams."