Even as US airlines work to recover from days of a disrupted operations, another risk looms on the horizon – that posed by new 5G-related aircraft-operating restrictions.

On 1 July, hundreds of aircraft in the fleets of US airlines will be unable to perform low-visibility landings under a Federal Aviation Administration rule intended to prevent 5G from interfering with radio altimeters.

The rule means that only jets with updated “5G-tolerant” altimeters will be permitted to perform such landings. Though most US aircraft have the new equipment, many do not.

Delta Airbus A220-300

Source: Delta Air Lines

Delta says none of its Airbus A220s have updated altimeters

Still, airlines insist they are ready to address 5G-related operational challenges.

“Some of our aircraft will have more restrictions for operations in inclement weather,” Atlanta-based Delta Air Lines says. “To mitigate long delays, Delta teams have the capability of moving assigned aircraft away from airports that stand to be impacted by weather.”

Trade group Airlines for America (A4A), says, “Thanks to careful planning, A4A member carriers are confident in their ability to maintain the integrity of their schedules, despite the impending deadline”.

Despite the industry long knowing of the 1 July deadline, the FAA says carriers have yet to update a fair number of aircraft.

“More than 85% of the domestic commercial airline fleet and about 66% of the international fleet are equipped with radio altimeters that can operate safely in the US 5G C-band environment,” the FAA says on 30 June.

In a 23 June letter, US secretary of transportation Pete Buttigieg said, “We continue to see a significant number of aircraft still awaiting retrofit, including many operated by foreign air carriers”.

The FAA’s rule specifically prohibits, starting 1 July, aircraft that lack updated altimeters from making instrument landing systems (ILS) approaches, from performing “automatic landing operations”, and from use to touchdown of certain guidance systems (including head-up displays and flight visions systems).

The restrictions will tighten on 1 February 2024, when an outright ban on operation by airlines of non-conforming aircraft takes effect.

A4A and Regional Airline Association (RAA) say their members have been updating jets in recent months, but that progress has been hindered by supply chain troubles.

“Most of the regional airline fleet are already equipped, and there are plans in place to manage the few remaining aircraft that are still being retrofitted,” RAA says. “Our members expect any impacts to be minimal going forward.”

Installation of a

Source: AT&T

A worker installs a “5G” antenna. The US aviation and telecom industries have been battling for several years over whether 5G poses safety risks to aircraft

Delta Air Lines says about 190 of its aircraft will lack 5G-tolerant altimeters as of the 1 July deadline, including “all” its Airbus A220s, “most” A319s and A320s, and “some” A321s.

Delta adds that all its widebody jets have been updated, and that its regional-airline partners have updated their aircraft “with very few exceptions”.

American Airlines and United Airlines say they have already updated their entire fleets, though neither says whether their regional airline partners have met the deadline.

The FAA set the 1 July deadline because that day wireless companies, including AT&T and Verizon, will begin operating 5G at “higher power levels”, according to Buttigieg’s letter.

The FAA and aviation industry fear that the 5G signals could interfere with radio altimeter readings.