The regulatory question surrounding airborne cellphone use involves two separate and independently applicable bodies of law — FAA regulations under 14 CFR 91.21 and FCC regulations under 47 CFR 22.925 — and the distinction between them is critical for any GA, Part 91, or commercial pilot to understand. These two rules govern different things entirely: the FAA rule addresses electromagnetic interference with aircraft systems, while the FCC rule addresses cellular network integrity on the ground. Both apply simultaneously, and compliance with one does not satisfy the other.
FAR 91.21 restricts the use of portable electronic devices (PEDs) aboard aircraft, but 91.21(b)(5) carves out a broad exception for any device the operator determines will not interfere with the aircraft's navigation or communication systems. This is the regulatory basis upon which GA pilots lawfully use iPads and iPhones running ForeFlight, Garmin Pilot, or other EFB applications in flight. The pilot-in-command, exercising operational authority, makes the interference determination. For most modern tablets and smartphones operating in airplane mode, that determination is well-supported — the aviation industry, including the FAA's own EFB guidance, has broadly acknowledged that these devices do not pose meaningful interference risk when cellular radios are disabled. Airlines operating under 121 similarly rely on this exception through FAA-approved policies that allow passengers to use devices in airplane mode.
The FCC's 47 CFR 22.925 operates on a completely different axis. That rule prohibits the active operation of cellular transmitters aboard airborne aircraft — not because of cockpit interference concerns, but because an airborne phone can simultaneously illuminate dozens of ground-based cell towers, creating network congestion and coverage degradation that the terrestrial cellular infrastructure was not designed to handle. Crucially, this rule prohibits cellular *transmission*, not the mere presence or non-transmitting use of a device. When a pilot uses ForeFlight on an iPhone that is in airplane mode with cellular radios disabled, no cellular transmission is occurring, and 47 CFR 22.925 is not implicated. The moment that phone is placed back into cellular mode and actively connecting to towers while airborne, the FCC prohibition applies — regardless of whether the FAA's interference exception under 91.21(b)(5) might otherwise be invoked.
For working pilots, the practical takeaway is that ForeFlight on an iPad or iPhone is entirely lawful in flight provided cellular data is disabled and the device is used as an EFB in airplane mode. Using Wi-Fi, Bluetooth for ADS-B receivers, or internal GPS on such devices raises no regulatory issue under either framework. However, actively transmitting via cellular — making calls, streaming data without airplane mode, or sending texts through the cellular network while airborne — places the pilot in violation of FCC regulations that carry their own independent enforcement authority, separate from the FAA. The FCC's rule has been in place since 1991 and has survived multiple proposed revisions; a 2013 FCC notice of proposed rulemaking to relax the prohibition drew significant opposition and was quietly shelved. Until that rule is formally revised, it remains binding on all civil aircraft operations in U.S. airspace regardless of certificate type or operating rule.
This dual-regulatory framework reflects a broader pattern in aviation where pilots must account for rules originating outside the FARs — FCC spectrum regulations, TSA security directives, DOT hazmat rules, and international ICAO standards among them. For operators running Part 135 or 91K flightdeck environments, internal policies should explicitly address both FAR 91.21 compliance and the FCC prohibition to ensure crews understand that "the pilot determines it won't interfere" does not create blanket authorization for any and all in-flight cellular activity. The cleanest operational guidance remains straightforward: EFBs and aviation apps in airplane mode are permitted and broadly accepted; live cellular use while airborne is not.