Airlines warn that 5G interference will wreak havoc with operations

The airlines are once again urging the Biden administration to stop the planned roll out of 5G broadband by AT&T and Verizon.
The CEOs of the 10 US passenger and cargo carriers that are members of the Airlines for America (A4A) wrote a letter on Monday saying that immediate intervention is needed to avoid significant operational disruption to air passengers, shippers, supply chain and delivery of needed medical supplies.
The C-Band spectrum will be used for 5G transmissions by AT&T and Verizon. The C-Band is closer to frequencies used by aircraft than has been allowed in the U.S.
Notices were issued by the FAA telling pilots not to perform low-visibility landings at nearly 100 airports that could be impacted by C-Band transmission. The notices will apply to aircraft with radio altimeters that have either proven not to be reliable within areas impacted by C- Band transmission or that have not yet been tested for such reliability.
When flying at altitudes of 2,500 feet and below, the attimetrics are important to measure the plane's distance from the ground.

The FAA cleared 45% of the US commercial fleet on Monday to perform low-visibility landings at 48 airports that will be most affected by 5G interference. Some of the approved aircraft include Boeing 757s,
The FAA expects to approve more Boeing planes in the coming days.
The agency said that even with the new approvals, flights at some airports may still be affected. The FAA is working with manufacturers to understand how radar altimeter data is used in other flight-control systems. If the weather is forecast at a destination where 5G interference is possible, passengers should check with their airlines.

Two weeks ago, A4A agreed to an arrangement under which AT&T and Verizon would begin C-Band transmissions Wednesday, while implementing six-month protection zones around 50 of the most impacted airports.
The harm caused by the deployment would be worse than the airline executives had thought.
They said that most of the airports that will have protection zones around them are among the airports that will be subject to flight restrictions.
The airline executives said that the restrictions will not be limited to poor weather conditions because radio altimeters provide critical information to other aircraft safety systems.

The executives said that the manufacturers had told them that there were huge swaths of the operating fleet that may need to be indefinitely grounded. Tens of thousands of Americans could be stranded overseas due to the lack of usable widebody aircraft.