(Reuters) - Three senior Democratic lawmakers on Tuesday urged the Federal Aviation Administration to address safety issues at Reagan Washington National Airport and maintain reduced air traffic after a series of troubling incidents.

Representatives Rick Larsen and Steve Cohen and Senator Tammy Duckworth in a letter seen by Reuters also urged the FAA to keep the hourly aircraft arrival rate at Reagan at reduced levels, at least until the Washington air traffic control tower is fully staffed up and fully addresses safety risks identified from the agency’s ongoing review.

Earlier this month, the FAA said it may further slow flight arrivals at Reagan Washington after a January 29 collision between a helicopter and an American Airlines (NASDAQ: AAL ) regional jet near the airport killed 67 people.