The Federal Aviation Administration has awarded a total of $3.3 million for construction projects at Washington National and Dulles International airports to improve safety and airline passenger convenience.

The biggest contract, for $1.6 million, will go for a new fire station and emergency equipment station at National Airport. The contract was awarded to Jonal Corp. of Silver Spring.

Shirley construction of Alexandria won a $617,285 contract to enlarge the concrete aircraft holding apron at the north end of Runway 18 -- the main north-south runway at the airport.

The other two projects are at Dulles International. Diamond Service Inc. of Columbus, Ohio, won a $648,264 contract to cut grooves in the three runways at Dulles. The grooves, which improve traction and aid drainage during rain, will be a first for the Dulles runways although runway grooves are widely used in aviation.

The other contract was awarded to Mechaneer Inc. of Arlington for $394,691 to expand the baggage claim section in the international arrivals area at Dulles.

The expansion, part of a continuing new construction program that is designed to avoid changing the exterior view of the architecturally significant Dulles terminal, is supposed to relieve a major bottleneck on evenings, when a host of international flights arrive at the same time.

All of the contracts were competitively bid and were awarded to the low bidders, according to David Hess, airport spokesman.