Additionally, the flight of modern airplanes depends largely on * computer control, and the lines of computer transmission data are distributed throughout the aircraft, the use of cell phones in the cabin, the electromagnetic waves emitted by the transmission lines will interfere with the transmission of normal signal transmission.
The electronic devices prohibited on the aircraft include cell phones, pagers, game console remote controls, amateur radio receivers, laptop computers, CD players and so on.
The electrical signals transmitted by cell phones, computers, radio radios, etc., in addition to their strength, which can affect the aircraft, they transmit frequencies that, if they happen to be the same or similar to the aircraft's frequency, together with the amplitude (or amplitude of the wave), can cause the most damage and dangerous conditions.
Throughout the flight of an airplane, pilots use onboard radio navigation equipment to maintain real-time contact with ground-based navigation stations and to control the flight path. In the case of low visibility, it is necessary to activate the instrument landing system for landing, that is, the use of blind landing stations on the runway to transmit electromagnetic signals to the aircraft to determine the location of the runway. The cell phone will not only emit electromagnetic wave signals during the broadcasting or answering process, but also keeps contacting with the ground base station in the standby state, and in its searching process, it has a strong continuity, although each time it emits signals for a short time. So the electromagnetic wave from the cell phone will cause interference to the aircraft's navigation system, and the impact is even greater in the case of low visibility. Aircraft in smooth flight, from the ground 6,000 meters to 12,000 meters, when the phone simply can not receive the signal, can not be used; in the takeoff and landing process, the phone may be able to get in touch with the ground base station, but at this time interference with the navigation system produces the most serious consequences.
Maybe some people will ask why there are no serious consequences for people who have used cell phones on airplanes in the past. This is because there are many factors that affect the interference of cell phones on airplanes. First of all, due to the difference in the sensitivity of each cell phone to receive signals, and the ground network contact situation is not the same, resulting in different interference; Secondly, the distance between the cell phone and the navigation station, the electronic cabin has a difference in the distance, resulting in interference is also different. However, at present, due to the different models of aircraft, the electronic cabin in the aircraft is located in different positions, passengers can not judge whether they are in the vicinity of the electronic cabin, therefore, the Civil Aviation Safety and Security Regulations clearly stipulates that: passengers boarding the aircraft to turn off the cell phones, computers and game consoles.
Additionally, places where the use of cell phones is prohibited include automobile gas stations and hospitals. According to the China Petroleum and Chemical Corporation, the person in charge of infrastructure, in the gas station should not play the cell phone, the main reason is that refueling or unloading oil, the air in the high content of oil and gas, flammable and explosive, and cell phone is not explosion-proof, and carries more static electricity, so there is a certain degree of danger.
Cell phones should not be used in hospital treatment areas and wards. The electromagnetic waves emitted by cell phones interfere greatly with medical instruments. The vast majority of wards and operating rooms in hospitals use monitoring systems, such as: cardiac monitoring, electroencephalographic monitoring, electromechanical monitoring. These instruments monitor various physiological parameters of patients. As the monitoring instruments are using digital technology to transmit telemetry signals wirelessly to work, its working principle is similar to that of a cell phone. When the monitoring instruments are interfered with, the correct parameters cannot be derived. If this happens to a patient who is seriously ill or undergoing surgery, the consequences are unimaginable.