UPDATE (3:39 p.m.): According to a statement from Delta, flight 937 returned to Tucson shortly after takeoff following indication of a mechanical issue with the plane’s left engine.
The crew followed procedures, Delta said, to return to Tucson International Airport and declare an emergency as a precaution.
“Nothing is more important than the safety of our people and customers, and we apologize to our customers for the delay in their travels,” the statement said…