In Washington on Wednesday,the National Transportation Safety Board held the first of three days of hearings into the deadly midair collision in January near Washington Reagan National Airport.
In all, 67 people were killed when an American Airlines jet and a military helicopter collided near DCA. It was the nation's deadliest plane crash in more than 20 years.
In hours of technical questions, NTSB members focused their inquiry on the military helicopter involved in the collision.
They want to learn more about the exact placement of certain flight instruments within the helicopter itself, like the altimeters that tell pilots what altitude they are flying at.
It comes after investigators had already identified 85 near misses around Washington Reagan National Airport, and found that military helicopters in that crowded airspace routinely flew with a key piece of equipment turned off.
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During Wednesday's hearing, NTSB Chair Jennifer Homendy addressed family members of the victims who are in the audience.
"Please know that your loved ones are why we fight so hard for safety," Homendy said. "They are why we are meeting here today for this investigative hearing. I do also want to commend each of you for your remarkable selflessness in the wake of a tragedy. You have courageously spoken out and advocated for important reforms to save lives and improve aviation safety. I hope the information that we uncovered during this hearing will support your efforts."
The investigation into the DCA collision is ongoing, and a report on the cause of the accident is not expected for some time.
The NTSB's hearing will last the rest of the week, wrapping up on Friday afternoon.
