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.

An altercation occurred at the Ronald Reagan Washington National Airport a month after the site bared witness to a major tragedy.