According to a report from The Wall Street Journal, starting from July 1st, aircraft without retrofitted sensitive radar altimeters in the US will not be able to land in low visibility conditions. This requirement, although not related to an existing safety issue, is in response to the increased power of 5G networks by US wireless companies. The concern is that the stronger signals from these networks could interfere with the radio waves used by radar altimeters to determine an aircraft’s altitude.

The implementation of the 5G network boost has faced delays and debates between the Federal Communications Commission (FCC) and the Federal Aviation Administration (FAA). Initially planned for January 2022, the power increase was postponed until July 2022. Eventually, a compromise was reached between wireless carriers and the FAA, setting the deadline for July 1, 2023.

Approximately 80 percent of domestic aircraft have already undergone the necessary altimeter upgrade. However, some major carriers, such as Delta and JetBlue, still have a portion of their fleet that needs to be brought up to the new requirements. Supply chain issues have been cited as a reason for the delay. On the other hand, United, Southwest, and American Airlines have reported that they will meet the deadline with all their planes. As for international flights entering the US, about 65 percent of the aircraft already have the updated altimeters, and airlines will prioritize using those aircraft whenever possible.

US Secretary of Transportation Buttigieg has expressed concern about the potential for delays or cancellations due to this requirement, calling it the most significant foreseeable problem affecting performance during the summer. The extent of the impact will depend largely on weather conditions, though it is worth noting that there are no imminent snowstorms expected.

By February 2024, all planes in the US will need to have updated altimeters, regardless of visibility conditions.