The head of the National Transportation Safety Board says if investigators were able to quickly find alarming data about the number of close calls in the years before the fatal midair collision over the nation’s capital in January,

The Senate subcommittee on aviation, space and innovation will question regulators about flight safety in response to the January midair collision.

A federal official admitted mistakes were made in a Senate hearing on the midair collision at Ronald Reagan National Airport that killed 67 people, as lawmakers continue to press top aviation and safety officials for answers on the congested airspace.