Family members of some of the 67 people killed in January’s midair collision in Washington listened to the US Army and Federal Aviation Administration take fiery questions from lawmakers for the first time Thursday at a Senate subcommittee hearing on the preliminary findings of the accident.

If investigators were able to quickly find alarming data about the number of close calls in the years before the midair collision over the nation's capital that killed 67 people in January, then aviation safety regulators should have seen the problem,