Renee Montagne talks with aviation reporter Stephen Trimble about airplane technology and black boxes.
Some friends and family of the 239 people who have been missing since Saturday have called their loved ones' cellphones and heard rings. Sadly, that doesn't mean the phones and their owners are safe.
Hoping to boost young people's enrollment in health care, President Obama appears on the web-based show Between Two Ferns
, where he submitted to questions from the comedian.
Also: The Senate passes Sen. McCaskill's bill about sexual assaults in the military; author Joe McGinniss dies; and in Venezuela, a student leader is killed in anti-government clashes.
Tensions are continuing to build in advance of a regional referendum on Sunday. Crimeans will be asked whether they wish to split from Ukraine and join the Russian Federation.