WASHINGTON, D.C.: Ten Democratic lawmakers in the U.S. House of Representatives have asked the Pentagon to reduce military training flights in the Washington, D.C., area.

Their request comes after a January mid-air crash between an American Airlines regional jet and a U.S. Army helicopter killed 67 people.

In a letter, the lawmakers also called for the Pentagon to require the use of ADS-B, a safety system that was not active on the Army helicopter during the crash near Reagan National Airport. Civilian aircraft must use ADS-B to share their location, but lawmakers say the military often does not use it for training flights.

Last Friday, the Federal Aviation Administration (FAA) permanently restricted non-essential helicopter flights near Reagan. It also banned helicopters and passenger jets from flying close to each other and restricted the use of two smaller runways when urgent helicopter missions are underway.

The lawmakers, including Representatives Don Beyer, Steny Hoyer, and Jamie Raskin, argued that many helicopter flights in the area are unnecessary and should be moved farther away.

On Thursday, the Senate Commerce Committee, led by Senator Ted Cruz, will hold a hearing on the crash. Witnesses will include the acting FAA administrator, an Army aviation director, and the head of the National Transportation Safety Board.

Airlines for America, a trade group representing American Airlines and other carriers, has also asked the FAA to reduce helicopter traffic permanently near the airport.

Transportation Secretary Sean Duffy said last month it was time to shrink unneeded military flights.

"If we have generals who are flying in helicopters for convenience through this airspace, that's not acceptable. Get a damn Suburban and drive - you don't need to take a helicopter," Duffy said.