GEOFF BENNETT: We're going to shift our focus now to the latest concerns around Boeing and aviation safety more broadly.

The aerospace giant remains on the hot seat over important questions about its manufacturing and production processes.

The head of the National Transportation Safety Board, Jennifer Homendy, told lawmakers her investigators still do not know who worked on the Boeing 737 door panel that blew off an Alaska Airlines flight back in January.

At the same time, The New York Times reported this week that Boeing and a key supplier, Spirit AeroSystems, failed a number of recent FAA audits.

Boeing reportedly failed 33 of 89 product audits.

FAA Administrator Mark (sic) Whitaker was asked about that on Monday.

MICHAEL WHITAKER, Administrator, Federal Aviation Administration: We have increased our audit and our oversight of Boeing pretty significantly since January 5.

If we see something that requires us to cease production or pull something down, we will do that.

But we're continuing that oversight and we're working with Boeing and demanding that they come up with a very detailed plan within the next 90 days to fix the quality issues that are out there.

GEOFF BENNETT: Equally unnerving, a series of problems on flights in just the last week, including several on United Airlines.

There have been half-a-dozen incidents for United, including one flight that had to turn around after an engine caught fire.

And, on Monday, a flight from LATAM Airlines dropped suddenly and temporarily in midair en route to Auckland.

The plane landed safely, but more than 50 people suffered injuries.

One passenger woke up suddenly to the scare.

BRIAN ADAM JOKAT, LATAM Airlines Passenger: I look up, and he's full length facing down and looking down at me.

And I look ahead, and there's another guy on the ceiling and there's two people flying through the air going across the aisles.

GEOFF BENNETT: And let's bring in our aviation correspondent, Miles O'Brien.

Miles, it's always great to see you.

So let's start with Boeing.

This Boeing audit conducted by the FAA revealed that the company failed large portions of that evaluation.

The company failed 33 of 89 audits after that door panel flew off the Alaska Airlines flight back in January.

Put that into context for us.

What more can you tell us about that?

MILES O'BRIEN: Well, Geoff, those numbers are kind of stunning.

The Boeing CEO early on used the euphemism quality escape.

That's a lot of escaping.

And that causes a lot of concern about what's going on, on that factory floor at Boeing.

But also, very importantly here, you have to ask the question, where was the FAA in advance of all this?

Why weren't these audits ongoing?

As we have discussed several times, Geoff, the FAA has moved to a system where manufacturers do their own inspecting.

Obviously, we have a problem there with a conflict of interest potentially.

But to the extent that there are FAA inspectors involved, in most cases, they're requesting and receiving paperwork, not necessarily putting boots on the factory floor and laying their eyes on potential problems.

So, when the FAA administrator says they need to rethink all of this, it's a big rethink, because the way it is done right now, clearly, it's allowing a lot of safety problems to escape into the market.

And that's not what anybody wants to hear.

GEOFF BENNETT: And the NTSB seems to be saying that Boeing isn't cooperating.

How do you interpret the comments from the NTSB that they don't even know who was working on that door panel that flew off?

MILES O'BRIEN: The NTSB would like to speak to the machinists that actually did the work on that door which escaped from the Alaska Airlines flight.

What happened?

What did they do?

What did they not do?

What were on the checklist or not?

And it's not a criminal proceeding.

This is just an effort to understand what went wrong.

This is how aviation gets safer.

You learn from it and you make better rules for the future.

But Boeing has so far blocked that effort.

And you have to ask the question, why would a manufacturer do that?

Wouldn't it be in the interest of aviation safety for those machinists to speak to the NTSB, so that lessons can be learned?

GEOFF BENNETT: We also learned this week that Alaska Airlines flight was scheduled for a safety check that same day the door panel blew off and that there were engineers who were concerned about warning lights before that.

You're a pilot.

Are there cases where it's OK to fly when warning lights are going off?

MILES O'BRIEN: Pilots have something called a minimum equipment list.

It's the stuff that you can -- it might be not working 100 percent correctly, but you could still dispatch and take off with.

These lights on their own were in that list.

In other words, you could fly and get it to maintenance in a reasonable course, as opposed to grounding the aircraft.

In retrospect, maybe that wasn't great.

However, there was no other signs or symptoms of trouble with the pressurization system.

And when I say that, either the crew or passengers would feel popping in their ears or hear a rushing of wind.

None of that was occurring.

So, for all that engineer and all those machinists knew, it was just a bad sensor.

And so the decision to wait until it got to Seattle, in retrospect, was probably an OK decision.

GEOFF BENNETT: Here we are some three months later.

Do we still know enough about the circumstances surrounding that Alaska Airlines flight?

MILES O'BRIEN: We're getting there.

But, I mean, it would be -- again, it would be nice to talk to all the parties involved, see exactly what happened, exactly what they were thinking.

Everything that is done in aviation has a checklist.

And the process of building aircraft are no different from that.

This particular activity, taking off that door to fix some rivets, was not in the system, so to speak.

It was kind of an ad hoc move to make a fix.

Those are the kinds of things, that kind of detail is really important to understand to understand how that slipped through the cracks and how those bolts weren't put in place.

GEOFF BENNETT: And, Miles, amid all of this, a veteran Boeing employee, a prominent whistle-blower involved in quality control, he died by suicide.

What more can you tell us about his case and his deposition?

MILES O'BRIEN: Well, John Barnett worked for a long time in the South Carolina plant for Boeing, which produces the 787.

And his whistle-blower case has revolved around quality control issues at Boeing.

And at the core of his testimony is the idea that parts that were taken out of the production line by workers, concerned that they weren't up to snuff and put off to the side, were not properly evaluated, but rather were put right back onto aircraft that are now flying around the world.

That's a big concern.

And that deposition was a very heated one from the company officials.

Now, what that might have to do with what happened later, we don't know, of course, but it's a tragic end to John Barnett's story, for sure.

GEOFF BENNETT: And, as we mentioned, there have been a series of incidents involving united flights and others involving Boeing planes with different airlines.

How concerning is all of this, big picture?

MILES O'BRIEN: Yes, it's kind of all over the map, Geoff.

You have cases where wheels are falling off.

That could be attributed to maintenance, an aircraft taxing off a runway, probably pilot error.

An engine flame out, that's the manufacturer, CFM, that makes the engines.

And then you have a 787 which had a precipitous fall between Australia and New Zealand.

What drives that all together?

It's hard to say, except I will say this.

The aviation industry was clobbered by the pandemic.

It lost experienced people in every quarter, on factory floors, in control towers, in cockpits, and the people that screw on the wheels to airplanes.

All those places lost experience during COVID, when people retired.

And so this industry, which is raring and back, and people are flying, is struggling to keep up with all that.

And it is worrisome.

GEOFF BENNETT: Miles O'Brien, appreciate your insights, as always.

Thanks so much.

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