A Piper Cheyenne twin-engine plane carrying a medical patient landed at Reno-Tahoe International Airport around 2 a.m. Wednesday without clearance from the tower and while the lone air traffic controller in the control tower slept, according to the Federal Aviation Administration.
The unidentified air traffic controller was unresponsive to radio calls and other communication attempts for 16 minutes, and has been suspended.
The FAA also announced that it is investigating two similar incidents at Boeing Field/King County International Airport in Seattle and Preston Smith International Airport in Lubbock, Texas.
The recent events come after an air-traffic supervisor accidentally fell asleep March 23 at Washington Reagan National Airport and a controller intentionally slept for hours at McGhee Tyson Airport in Knoxville on February 19.
The Federal Aviation Administration is responding to the incidents by adding an additional air traffic controller to the midnight shift at 27 U.S. airports that currently are staffed with only one controller during the midnight shift.