WASHINGTON, March 21 (Reuters) - Ten U.S. House of

Representatives Democratic lawmakers on Friday urged the

Pentagon to reduce military training flights in the Washington,

D.C., area after a January midair collision between an American

Airlines ( AAL ) regional jet and a U.S. Army helicopter killed

67 people.

The lawmakers, in a letter, said they also want the Pentagon

to require the use of a key safety system known as ADS-B that

was not operating on the Army helicopter at the time of the

collision. "To the maximum extent practicable, military training

flights should be conducted outside the National Capital

Region," Representative Don Beyer and the other Democrats wrote.