Have you used a mobile phone in a small plane?

[Jim Logajan]

When I pilot a plane I don't turn on airplane mode on my iPhone - I can still receive and make calls, though I've never done either (yet). On commercial flights I turn on airplane mode because they ask. Not because I think it will cause problems with aircraft systems. After all, my iPhone has a shit load of receivers and transmitters that manage to play fairly well with each other in close proximity:

• 5G (sub‑6 GHz and mmWave) with 4x4 MIMO
• Gigabit LTE with 4x4 MIMO and LAA
• Wi‑Fi 6 (802.11ax) with 2x2 MIMO
• Bluetooth 5.0
• Ultra Wideband chip for spatial awareness
• NFC with reader mode
• Express Cards with power reserve
• GPS, GLONASS, Galileo, QZSS, and BeiDou
• Digital compass
• Wi‑Fi
• Cellular
• iBeacon microlocation

 

[Bob Noel]

remember how early GPS installations had problems with certain radios?

You would like to have equipment installed in the aircraft to be ok wrt EMI/EMC. But, hey, everyone's an expert on that (EMI/EMC) because some electronic thing they have works ok ....as far as they can tell.

Some stuff has failure modes that can be surprising.

LORAN worked really good on the water. It seemed to be really good over land. But in rain/precip it had some problems and also groundwater tended to move the computed position solution.

Anyway, to answer your question: No. never had the need or desire.

 

[rotorwrench]

Not because I think it will cause problems with aircraft systems. After all, my iPhone has a shit load of receivers and transmitters that manage to play fairly well with each other in close proximity

Except you need to put this into context. The first cell phone use ban on aircraft was from the FCC and not the FAA. Only after cell phones became more popular and smaller did the FAA issue their own rules.

While there are/were NASA/FAA documented instances of probable interference by cell use, the main issue was none of the prevailing certification standards required testing of cell phone frequencies. Overtime these standards were upgraded to include cell freq testing for certification, however, these new standards did not affect installed legacy equipment.

Enter 5G. So while the EASA/EU are permitting 5G phones for aircraft use, the FAA/US has issued Airworthiness Directives to prevent their use. The main reason is EU 5G is considerably different than US 5G on several levels which created additional problems in the industry. For example, this has been a major problem with the EMS helicopter industry and their radar altimeter mandates.

However, once various legacy equipment is upgraded, the 5G issue in the US will eventually be resolved from what I understand.

Regardless, it’s the upgraded standards on both ends of the spectrum that allow your freq checks to work without issues. Unfortunately, Part 135/121 ops are required to follow a few more rules/regs than your Part 91 rules at the moment when it comes to cell phones hence the greater restriction of their use..

 

[Jim Logajan]

Unpredictable interference is a concern, but the small planes I fly have few fancy electronics. My phone and tablet computer typically being the most sophisticated electronics on board.

As I understand it, Airplane Mode shuts off Cellular, Wifi, Bluetooth, and sometimes even the GPS receiver (not sure why, unless some concern over the radiation from superheterodyne receiver local oscillator? Or do they use SDR these days?)

However, in order for a pilot of a small airplane to connect their tablet computer to an ADS-B system, EFIS, or external GPS they have to turn on either Wifi or Bluetooth, depending on the system. Some airlines now offer Wifi internet access, so some aircraft appear to have been cleared. That leaves Cellular as the lone banished RF application. And I have read (but am unable to confirm) that upgrades to cell towers and handoff algorithms make that issue mostly moot, though regulations written decades ago are presumably slow to change.

 

[rotorwrench]

That leaves Cellular as the lone banished RF application.

Not hardly. There are many other electrical equipment, or PEDs (Personal Electrical Devices), that have limitations or prohibitions from operating on airborne aircraft as this has been an issue since the early 60s. Cell phones and the like are simply the current flavor of decade due to their popularity. There's a number of FAA guidance docs out there that give more details and history with AC91.21 being a good one.

However, unless you are flying under IFR at the time none of the FAA cell rules would technically apply to you personally per Part 91.21. As I recall the only rule that may catch you using a cell phone without approval, is an FCC rule for a Private Part 91 VFR flight.

 

[Jim Logajan]

As I recall the only rule that may catch you using a cell phone without approval, is an FCC rule for a Private Part 91 VFR flight.

Perhaps you mean 47 CFR § 22.925 Prohibition on airborne operation of cellular telephones.? Yes, that makes it illegal for everyone to use a cell phone while airborne. That persists because of social pressure, not for technical reasons. It has now been 10 years since this happened:

"The Federal Communications Commission voted 3-2 Thursday to consider lifting its ban on in-flight cell phone use."
...
"The FCC has banned in-flight calls for technical reasons. But new technology has made that ban obsolete, the commission says, and there’s no reason to continue it."
...
"“I’m the last person in the world who wants to listen to someone talking to me while I fly across the country,” FCC Chairman Tom Wheeler – who proposed the change – told a congressional panel Thursday. “But we are the technical agency, and we will make the rules for the way the new technology works.”

Source: https://www.cnn.com/travel/article/fcc-cell-phones-on-airplanes/index.html

 

[rotorwrench]

Perhaps you mean 47 CFR § 22.925 Prohibition on airborne operation of cellular telephones.?

I'll take your word it is. Back when we 1st looked at putting cell phones into certain helicopters at the old day job, we had to get approval/exemptions from both the FAA and FCC to install and use them. However, as the UHF radio became more advanced most of the onboard cell equipment was removed. In its place to augment those radios and where needed sat-phones were installed on the aircraft.