RENO, Nevada - An air traffic controller was suspended after being asleep while a medical flight was landing in the state of Nevada, marking the fifth lapse so far this year among controllers at US airports. Four involved sleeping controllers.

In response to the lapses, the Federal Aviation Administration announced Wednesday it was immediately putting a second controller on the midnight shift at 26 airports and a radar facility around the country that have only one overnight person.

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"I am totally outraged by these incidents. This is absolutely unacceptable," Transportation Secretary Ray LaHood said in a statement. "The American public trusts us to run a safe system. Safety is our No 1 priority and I am committed to working 24/7 until these problems are corrected."

The controller at Reno-Tahoe International Airport was out of communication for about 16 minutes when the aircraft carrying at least three people was landing about 2 am local time Wednesday, the FAA said. No injuries were reported.

Still, the head of the airport called for increased staffing.

"The flying public needs an assurance from the FAA that this situation will be addressed at all airports," airport chief Krys Bart said early in the day.

She said the pilot of the medical flight and airport staff had tried to contact the controller multiple times without success. The FAA said the pilot was in contact with regional radar controllers in northern California during the landing.

The FAA last month put two controllers on duty during the midnight shift at the Reno-Tahoe airport but went back to one controller several days later after implementing new procedures, FAA spokesman Ian Gregor said.

Elsewhere, two jetliners landed at Washington's Reagan National Airport last month without tower assistance after the lone air traffic supervisor fell asleep.

An investigation by the FAA uncovered a second incident of an air traffic controller sleeping on the job in February during the midnight shift at McGhee Tyson Airport in Knoxville, Tenn.

The agency also said a controller in Seattle had been suspended for falling asleep during a morning shift on Monday. The controller already faced punishment for falling asleep on two other occasions during an evening shift in January, the FAA said.

In addition, two controllers in Texas were suspended after two failed handoffs two weeks ago.

LaHood previously ordered an examination of controller staffing at airports across the nation and directed that two controllers staff the midnight shift in Washington.

A separate investigation was ordered by the House of Representatives Transportation and Infrastructure Committee.

Sen. Harry Reid said the Reno incident was unacceptable and his office was asking the FAA that a minimum of two air traffic control personnel work in the tower at all times.