“Please turn off electronic devices such as mobile phones and laptops when taking off and landing, because they may affect the aircraft system.”-General instructions on the aircraft. Some airlines require passengers to turn off their mobile phones during the entire flight. However, someone wonders (especially engineers) how correct this might be. If electronic devices can disrupt the aircraft’s communication and navigation systems and may cause the aircraft to crash, you can be sure that the Department of Homeland Security will not allow passengers to worry about carrying a mobile phone or iPad into a plane that may be used by terrorists.
Potential electromagnetic interference in aircraft systems is the most common argument forbidding electronic passenger equipment on aircraft. In theory, active radio transmitters such as cell phones, small walkie-talkies or remote control radio toys can interfere with the aircraft. This is especially true for older aircraft that use sensitive instruments, such as galvanometer-based displays. Technically, the more wire turns around a substance (iron core, carbon core, or just hollow), the greater the impact of “radio waves” on a single electron. In other words, the mobile phone’s radio waves push electrons toward the coil with increasing force, which affects the measurement.
The galvanometer has a large number of coils and very few enameled copper wires, and is extremely sensitive to small electromagnetic stimuli. However, these have been replaced by new technologies, and I think these new technologies have been blocked. Since many old aircraft are still in operation, their electromagnetic radiation resistance will deteriorate over time unless they are repaired and maintained from time to time. But decades of rules still exist, but there is no evidence that anyone reading e-books or playing video games when taking off or landing today puts safety at risk.
Another reason I found most useful is that, for example, when making a call B. 10,000 feet, the signal is transmitted back from multiple available base stations instead of from one. Frequent switching between units will cause a lot of network overhead and block the local network, which is why the Federal Communications Commission (FCC) and not the Federal Aviation Association (FAA) prohibit the use of units on aircraft. Because the tower may be within a few miles of the aircraft, it may need to receive the phone with the highest received power to receive it. This increases the risk of interfering with electronic equipment in the aircraft. However, the FCC has allocated spectrum in the 450 and 800 MHz frequency bands for use in equipment designed and tested for “safety of air-to-ground services”, and these systems use ground stations that are spaced apart. 450 MHz service is mainly limited to “general aviation” users in business jets, while the 800 MHz spectrum can be used for both business jets and general aviation.
All in all, it can be said that the radio frequency used for air traffic is separated from commercial use. In addition, aircraft wiring and instruments are shielded to prevent them from being interfered by commercial wireless equipment. The base station (called Picocell) has almost no power and the network area created is large enough to capture the aircraft cabin. The base station forwards the telephone service to the satellite, which is connected to the cellular network on the ground. The network control unit in the aircraft is used to ensure that the mobile phone in the aircraft is not connected to the base station on the ground. It blocks terrestrial signals, so when the call is established on the passenger’s cellular network, the phone will not be able to connect and remain idle. Because the Picocell antenna in the aircraft will be very close to the passenger and the metal shell of the aircraft,
While researching this topic, I encountered many interesting reasons to restrict the use of mobile phones on airplanes. Some of them are listed below:
1. Airlines need to control passengers, and the best way to maintain a bullock atmosphere is just some rules from the start of takeoff.
2. Obstacles are clearly political, not technical. No one held a supervisory position and did not want to change the policy that was later seen as a factor of collapse. Therefore, it is much easier to do nothing and keep the strategy unchanged in the name of “warning.” (Since older aircraft with simulation systems may still be prone to failure, it is best to keep the rules consistent.)
3. FCC (not FAA) prohibits the use of mobile phones and other wireless devices with a normal frequency of 800 MHz because they may interfere with terrestrial wireless networks. This also blocks the terrestrial network because the signal is transmitted back from multiple base stations.
4. The mobile phone will interfere with the aircraft’s communication and navigation network-please believe what the mobile phone tells you :).
5. Because the tower may be several miles below the aircraft, the phone may need to be transmitted at maximum received power to increase the risk of interference with the aircraft’s electronic equipment. Similar to point 4.
6. Airlines may require users to turn off their takeoff and landing equipment, and then allow them to restart all equipment immediately, resulting in more unnecessary aircraft interruptions. This will increase interference, so it is best to limit the phone for the entire duration.
7. Limit the use of equipment with batteries.
8. Some portable jammer devices may not cause interference after being turned on. However, if you keep 50 to 100 or more devices and interfere with the aircraft communication system, the situation may be different. In addition, the crew could not easily determine what equipment caused the problem. It is best to limit the use completely.
9. If mobile phones are allowed, terrorists can use mobile phone signals to detonate bombs.
10. Airlines support the ban on the use of mobile phones because they do not want passengers to choose in-flight phone services. This may be correct because the telephone service may be very profitable for the companies involved.
11. Although all aircraft cables are shielded, as time goes by, the shielding layer may deteriorate or be damaged. Unshielded cables exposed to cell phone signals can affect navigation equipment.
12. Another reason may be to inform passengers about important notices and safety procedures for pilots and crew members, otherwise these notices and safety procedures will be ignored. In addition, these devices may cause personal injury in an emergency, so they should be turned off during landing and takeoff. The idea at the time was that passengers might move them away instead of grabbing them because they could not operate the device.