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

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.

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.