When senators grilled the Federal Aviation Administration last week about how the agency could have let the high number of close calls between helicopters and commercial jetliners occur at Ronald Reagan Washington National Airport,

The arrest of an F.A.A. employee on assault and battery charges comes as flight operations at the airport have been under scrutiny since a passenger jet and an Army helicopter collided in January.

In the aftermath of the tragic midair collision over the Potomac River in Washington, D.C. in January, authorities have been working hard to making operations at Ronald Reagan Washington National Airport safer.