Ground Stop Highlights Chronic Vulnerabilities in Air Traffic System

The nationwide ground stop that brought air travel across the country to a halt Friday evening has highlighted persistent weaknesses in the Federal Aviation Administration’s aging air traffic control infrastructure that has had several disruptive failures in recent months.

Officials called the rare ground stop after outdated communications lines became overloaded and began to fail, interrupting communication lines between air traffic controllers and pilots, according to Transportation Secretary Sean Duffy and Homeland Security Secretary Markwayne Mullin.

The breakdown occurred less than two months after a circuit failure and severed fiber optic cable caused crippling ground stops and delays at airports along the East Coast. Smaller outages unfolded in October at Raleigh-Durham International Airport in North Carolina and George Bush International Airport in Houston, when contractors accidentally cut into fiber line.

The Friday ground stop, which was only the third the F.A.A. has issued this century, eclipsed the fallout of previous air traffic communications equipment failures. The F.A.A. has yet to identify precisely what caused communication lines to falter.

But the successive episodes have underscored the structural vulnerabilities that continue to hamper air traffic controllers’ ability to safely manage flight traffic, even after concerted efforts to make improvements. And they raised questions about whether the federal authorities have done enough to create backup systems and redundancies to prevent disruptive or even catastrophic failures.

For decades, the air traffic communications have relied on a system that runs on analog copper wire, floppy disks and alphabetical keyboards so old that the F.A.A. has difficulty sourcing spare parts. Last year, Congress approved $12.5 billion in funding to help pay for upgrades, after a series of outages in an air traffic control facilities, including the one serving Newark Liberty International Airport, caused alarming losses of radar and other communications capabilities.