GEOFF BENNETT: Air traffic controllers at Newark Liberty International Airport again lost contact with airplanes yesterday.

It's the fourth such incident at that airport in less than a month and the latest in a string of alarming incidents and close calls around the country, including a 90-second communication breakdown in Denver last week and close calls on runways at La Guardia and Chicago Midway.

To ease congestion at Newark, the FAA announced today it will substantially cap the number of flights there for the summer and much of the fall.

For more on all of this, we're joined now by David Grizzle.

He was the chief operating officer of the FAA's Air Traffic Organization during the Obama administration and he's also a former senior vice president of United Airlines.

Great to have you here.

DAVID GRIZZLE, Former Air Traffic Organization COO, Federal Aviation Administration: Glad to be here, Geoff.

GEOFF BENNETT: So you once oversaw the air traffic control systems.

Why are we seeing all of these issues apparently so suddenly?

DAVID GRIZZLE: Almost all of these communication lapses are the result of this 1980s vintage communication technology that the FAA is still running.

It's not been used in the private sector for over a decade.

And the telcos are ceasing to support this communication technology.

We have all been in the situation of where we receive a notification that we need to update our phone or an app or it will stop working.

Well, the FAA has been receiving update notifications for a number of years, but they have not had the budget in order to actually update the system.

GEOFF BENNETT: What about the impact of the Trump administration cuts?

Because some of the FAA jobs that were eliminated had direct roles in supporting safety inspectors and airport operations.

That's according to the union and former employees.

DAVID GRIZZLE: Yes, none of these cuts would have actually affected this problem, which long predated the Trump administration.

GEOFF BENNETT: The FAA oversees some 50,000 flights each day.

And, last year, a government audit found they continue to be slow to modernize their most critical and at-risk systems.

What kind of technology are the controllers using?

And why is it so hard to update?

DAVID GRIZZLE: The systems that they are using are the very best systems of the 1980s.

Part of the problem is the way that the federal government acquires new technology.

They do it about every 40 years, which means that when they do in fact install new technology, it's over budget, behind schedule, and is outmoded by the time they actually install it.

GEOFF BENNETT: So what does a real overhaul look like?

What would be required?

DAVID GRIZZLE: The first thing that needs to be done -- and this is the plan of Secretary Duffy -- is to, first of all, arrest the descent, to deal with the most safety-critical systems first, to, in essence, shore them up, and then begin installing on an incremental and iterative basis the new technology that we need, so that we don't find ourselves 40 years from now with 40-year-old technology.

GEOFF BENNETT: Staffing is another issue, as you well know.

A New York Times analysis last week found that 99 percent, 99 percent of air traffic control facilities in the U.S. are operating at below recommended staffing levels.

Why are we so critically understaffed when it comes to air traffic controllers?

DAVID GRIZZLE: We are about 3,000 controllers understaffed.

The plan is to hire 2,000 during the next year, but we are at a generational high in retirements.

Plus, more controllers are simply resigning because they're burned out.

And so unless we actually up our hiring numbers and change the processes and the technology we use for training them, we're not going to close that gap.

GEOFF BENNETT: That doesn't sound like an immediate fix.

DAVID GRIZZLE: It is not an immediate fix.

GEOFF BENNETT: What does that mean for airline safety?

DAVID GRIZZLE: First of all, the controllers have consistently preserved safety by reducing efficiency.

And so the airspace is still extremely safe.

You may have a lot of delays, but Secretary Duffy is addressing that by pulling down at Newark the capacity, so that they will only be scheduling the number of flights that they can efficiently handle with the challenges that they have right now.

GEOFF BENNETT: The transportation secretary has also blamed the Biden administration for what he calls a lack of investment in this system.

Is there any truth to that?

DAVID GRIZZLE: The Biden administration could certainly have done more, but the problems the FAA faces long predated the Biden administration.

GEOFF BENNETT: There's an air traffic controller who oversees flights at Newark who gave an anonymous interview published today in The Times of London.

And she says this -- quote -- "I deliberately avoid my own airport when booking flights, even if the alternatives are more expensive and less convenient.

If Newark's air traffic control problems don't get fixed, I believe it's only a matter of time before we have a fatal crash between two planes."

What's your reaction to that?

DAVID GRIZZLE: I appreciate this controller's concern, but I come back to what I said earlier.

These controllers are consummate professionals, and they maintain safety by slowing down the traffic.

That's the reason that you have seen such massive cancellations and delays at Newark.

They are doing only what they can do safely.

GEOFF BENNETT: So, heading into the summer travel season, we should expect more disruptions, more delays, more cancellations?

DAVID GRIZZLE: Yes, until the schedule reductions go into place, at which time we will only be scheduling the number of flights that can be safely and efficiently handled.

GEOFF BENNETT: David Grizzle, thanks so much for your insights.

I appreciate you being here.

DAVID GRIZZLE: Thank you.