"I've read about 5G interfering with avionics. Does this mean I can’t use my 5G phone in the air?" — Bobby M.
“This is really a two-part question. FAA is concerned that 5G signals may interfere with radar altimeters. Unless you have a radar altimeter in the panel, fly approaches to CAT II or CAT III minimums, or own an airplane with emergency autoland, interference from 5G towers shouldn’t be an issue.
Using a 5G phone in flight still may be a problem. FAA doesn’t explicitly forbid using a cell phone during flight. Instead, FAA addresses the use of all portable electronic devices in AC 91.21D. If you operate under Part 91, the advisory circular essentially says that, as PIC, you should conduct tests—while VFR—to confirm that everything plays well together in the aircraft that you fly. If you upgrade to a 5G device, it’s prudent to repeat those tests.
The AC also cites and endorses long-standing FCC regulations that prohibit making calls while airborne, unless the phone is connected through an approved system installed in the aircraft. FCC’s primary concern seems to be interference with the cellular network on the ground, which isn’t designed to handle fast-moving signals that boing from tower to tower like pinballs.
Recent experience using modern personal electronic devices, especially EFBs, indicates that they don’t interfere with contemporary avionics. Instead, the issues with making a phone call while flying seem to be establishing and maintaining a reliable connection to the cell towers below.
Pilots have debated the FCC rules for a long time. However, your primary concern about airborne cell phones probably shouldn’t be conflicting radio signals or hearing only every third word of a conversation. Using a cell phone to send a text or to take photos and video can cause much more serious interference—by distracting you from your primary task: Flying the airplane.”
Do you use your cell phone for calls and texts in the air?