Delta Air Lines announced on Thursday that it has completed the update of radio altimeters in its in-service fleet of airplanes to prevent potential 5G C-Band interference. In June, Transportation Secretary Pete Buttigieg had warned that airlines may face operational difficulties during bad weather if they had not make the necessary updates before the July 1 deadline.
Delta had approximately 190 airplanes that were yet to be equipped with the updated technology before the deadline, including all its Airbus A220 planes. Delta confirmed that all planes in service have now been updated, with only a few aircraft undergoing maintenance, which will also be outfitted with 5G-compliant radio altimeters upon their return to service. Delta stated that there was no significant impact on operations between July 1 and the completion of the work.
There have been concerns that 5G services could interfere with airplane altimeters, which are crucial for providing data on a plane's height above the ground and are essential for safe landing during bad weather. This led to brief disruptions at some U.S. airports last year as international carriers canceled some flights. Last year, Verizon and AT&T agreed to delay some C-Band 5G use until July, as air carriers worked to retrofit airplane altimeters. Major U.S. wireless carriers agreed to some voluntary actions to address aviation safety concerns, while also allowing them to increase power levels to get to full C-Band use on July 1.
Buttigieg told Reuters in an interview on July 20 that the transition to make airlines 5G-compliant went better than expected with minimal disruptions. Buttigieg stated that while airlines were mostly prepared, the effort "took a lot of pressure." He further added "It took multiple moments where we had to really just make sure they could read our body language that we really were serious...I don't think the airlines believed us early on." According to Buttigieg, as of late June, over 80% of the domestic fleet serving U.S. airports had been updated, but many aircraft operated by foreign carriers were still awaiting retrofit. This could result in increased delays and cancellations, especially on days with bad weather and low visibility.