AMNA NAWAZ: The National Transportation Safety Board has wrapped up a three-day investigative hearing into the midair collision between a helicopter and a passenger jet in Washington, D.C., that killed 67 people back in January.

New information confirms the crew of the Black Hawk helicopter faced several problems, including incorrect altitude measurements and issues hearing air traffic controllers.

Aviation correspondent Miles O'Brien is here to unpack it all.

So, Miles, three days of public hearings.

Do we have a better understanding of what went wrong?

What stood out to you?

MILES O'BRIEN: We do, Amna.

One thing that stood out to me is, this was a very contentious NTSB hearing.

That normally doesn't occur that way.

And a lot of the focus and the ire was directed at the Federal Aviation Administration.

We have to begin with the fact, Amna, that the tower at Washington Reagan Airport was understaffed.

One controller was handling two frequencies, the fixed-wing airliner coming in for landing and the helicopter traffic designed to fly beneath that flight path.

That controller was overwhelmed.

And, as you pointed out, inside that darkened Army helicopter on a training mission, there was confusion on communication.

There was a little bit of confusion about what altitude they were at.

And, ultimately, when the controller said, do you see the airliner, they looked at apparently another aircraft and said, yes, we do.

But it wasn't the aircraft that they ultimately collided with.

So, a series of confusing events, and ultimately, at the root of it, an overwhelmed flight controller who was handling two frequencies where two people should have been assigned.

AMNA NAWAZ: And, Miles, as we know, the families of the victims were attending the hearings.

They were hearing all of these details.

It had to be difficult for them.

But they also heard Jennifer Homendy, who's the NTSB chair, criticize the FAA, the Federal Aviation Administration, for not taking ownership of the collision, she said, and also said the agency ignored warnings after one of their towers had flagged a safety risk.

Take a listen.

JENNIFER HOMENDY, Chair, National Transportation Safety Board: But you guys are pointing out, well, our bureaucratic process, somebody should have brought it up at some other symposium.

Are you kidding me?

Sixty-seven people are dead.

How do you explain that?

Our bureaucratic process?

Do you know we actually added up how many steps it takes to get from the tower to headquarters to figure out - - and we ran all sorts of scenarios, how many steps it takes to get a policy change.

Twenty-one steps.

Fix it.

Do better.

AMNA NAWAZ: So, Miles, what was and what should be the FAA role here?

MILES O'BRIEN: Yes, 21 steps, bureaucratic inertia, to say the least, and ultimately costing a lot of lives.

Amna, this architecture of airspace in Washington for years was an area of great concern.

To have helicopters fly beneath that flight path with only 75 feet margin of error was clearly a safety issue, and yet the FAA for years did nothing about it.

Amna, over the past three years, there were no less than 85 near-collisions in that sector.

And that is a system blinking red, and the FAA did nothing.

AMNA NAWAZ: Miles, I have to ask you, because folks will have seen a number of other headlines about airline travel, one severe turbulence on a Delta flight in which a number of people were injured, another close call over North Dakota between a B-52 bomber and a Delta jet.

Is it still safe to fly?

MILES O'BRIEN: Statistically, it is.

It's still the safest way to get from point A to point B.

But we are seeing the system developing stress fractures, Amna.

The understaffing, the bureaucratic inertia, the safety redundancies built into this system are being shaved away.

And this accident we have just been talking about, this midair, is a warning call that the system is in trouble and it's time to invest in the people, the personnel and the technology to modernize this system and take these serious safety concerns much more seriously.

For years, Amna, people in the aviation world have said the FAA has a tombstone mentality.

Unfortunately, that's what we're seeing here.

And it's time that changed.

AMNA NAWAZ: Miles O'Brien, thank you, as always, for your time.

MILES O'BRIEN: You're welcome, Amna.