twojs1b t1_j2ue3dv wrote
What's your take on cellphone and other electronics on board possibly causing interference with aircraft equipment?
Mikeyme1998 OP t1_j2uifnl wrote
I really like this question. "Interference" is such a broad term, but what is most in the context of this question and the use of cellphones will be cellular signals and things like wifi, bluetooth, etc... all wireless signals that a cell phone or laptop typically sends and receives.
Within an aircraft itself, wireless transmission between avionics equipment is not used (besides sometimes having a bluetooth enabled audio panel on small privates, to listen to music like a car). There is virtually no way for a wireless signal as small as what a cell phone uses to interfere with avionics equipment busses within the aircraft. It is far more likely that the other wires within a bundle will cause issues via eddy currents, but we have shielding for any high power wires that risk this type of issue.
Now the big dilemma, especially recently, is with the cell phone signals interfering with equipment that receives its OWN traffic from other sources, IE. GPS, VOR, ADF, etc. Every electrical device (generally speaking) that sends and receives wireless signals does so via frequencies, 2.4GHz wifi, 5G or LTE cell towers, etc. All bands of aviation equipment (comm radios, NAV radios, etc) have been easily tunable and isolated from consumer electronics, until the large 5G debacle that came up a few months ago. This was the closest that the industry got to actually having a proper bandwidth conflict in recent memory, since 5G cellular devices are high power and very close to a specific set of equipment used in aircraft called the Radio (or Radar) Altimeter. I won't get too into the technicalities (if youre interested I wrote quite a long piece regarding this here) In laymans terms, this piece of equipment uses a beam of frequencies that sweeps up and down from about 4.2 to about 4.4GHz, and shoots it at the ground. Depending on the received signals in reference to the signals it is sending at any present time, it can determine the distance from the ground that the airplane is to a very precise degree. Because of this, many things that a pilot relies on during landing are dependant on the radio altimeter readings. They are especially important during low visibility landings.
The worry was that since cellphone towers are ground based, high energy, and close to the bandwidth, that there would be interference and faulty readings received in the cockpit. However, steps have been made in most developed countries to avoid the use of 5G and aiming them directionally away from runways. I have never personally heard of a pilot who has had issue with his equipment due to 5G or any other electronic users on the aircraft. The biggest reason, IMO, that airliners ask you to put your electronics away is so you are aware and attentive to the safety briefings and your surroundings in the event that an emergency were to happen at critical flight points, i.e takeoff and landing.
TL;DR: Airplane mode does not save avionics equipment, and the likelihood of your phone affecting anything in the cockpit is nearly zero.
zookeepier t1_j2xps7t wrote
To add to this, avionics are required to pass DO-160 environmental testing, which includes interference. So that testing should show that the equipment can't be interfered with by outside signals of X power. If they do interfere, then that's an indication that the testing was done incorrectly or didn't pass.
HerderOfNerfs t1_j2yvp5y wrote
With 5G it's more the ground based equipment that presents a problem. But it's not so bad in Canada as the regulator has more say. In the US, it was a big deal, especially when the FAA Advisory Directive related to 5G first came out. AT&T and Verizon seem like they had more say in ground based antenna placement and power. Boeing has gone to great lengths to show that interference is minimal or non-existent in a lot of the airports listed in the AD.
WateredDownTang t1_j308fu7 wrote
Recently in Canada there has been issued NOTAMS (notice to airmen) where 5G may or may not interfere with certain functions in auto-land equipped planes. That is really the only new news about cell reception and flying
HerderOfNerfs t1_j317tya wrote
Bottom line is Canada was ahead of the curve and created protection zones around Canadian runways to limit antenna transmission power to a certain spec. Furthermore, they have exclusion zones that prohibit antenna installations within a specific area around the runway. They didn't do this in the US. Risk is very much mitigated due to these actions.
j0mbie t1_j2xa39i wrote
It's also partially a hold-out from older tech cell phones that definitely used to interfere. I used to have a cell phone around 2005 that if placed anywhere near a speaker that was powered up but not transmitting audio, would cause noticable interference any time there was a phone call coming in. I could tell my phone was about to ring about 1 full second before it actually rung. I've been told that pilots around that time were having similar issues, but it seems like that's not the case anymore.
[deleted] t1_j2xl5jg wrote
Phones interfering with speakers is irrelevant to the topic at hand
j0mbie t1_j2yg2no wrote
My point is that the phones would interfere with the speakers used for the pilots' radios. I'm not sure if it was the speakers themselves, the radio part, or just because all of that was more sensitive, but I know that pilots were complaining about it.
VertexBV t1_j2xd5gs wrote
I remember the dirka-dirka speakers would make when your phone was nearby.
Redebo t1_j2y5i5x wrote
Mine sounded a bit more like dinkin flicka, but that could be because i grew up in an apartment.
Noghlin t1_j2y1rsc wrote
I still sometimes get that sound in my headset from cellphones. It's not a big problem though, just an inconvenience.
Poncho_au t1_j2vtorn wrote
Aren’t most airlines globally now allowing Bluetooth and WiFi inflight? They are in Australia.
I think the historic reasons for technology off inflight was a near entirely unfounded fear of interference.
The reasons for putting certain devices away during takeoff and landing is the risk of flying objects.
The reason airplane mode is still mandated on flights to my understanding is because of the likelihood that people will start taking calls and being even more annoying during flights.
theslowcrap t1_j2xd1jv wrote
Would a cellular connection work well at cruise speed?
Mikeyme1998 OP t1_j2xmmpr wrote
Not at all, in fact once you get above a few thousand feet above ground level, the cell towers simply wouldn't reach you. Contrary to what you might think, cell towers are very directional and don't propagate particularly well. That's why you don't get signal in valleys etc. Same goes for in the air, there's no point in pointing the dishes UP, so you have almost no signal at all unless it's some bounced waves off of mountains
VertexBV t1_j2xdhgg wrote
I read somewhere there were concerns on the telco side about users switching too quickly from one cell to another, or reaching too many towers at the same time, but this was a long time ago.
Viewing a single comment thread. View all comments