Mobile phone usage on board of the aircraft will seriously disturb the communication system of the aircraft endangering the flight. The aircraft relies on the communication and operating system which are linked with each other. In the take-off, flying and landing process, the pilot is unable to execute the commands he receives unless the connection with the ATM towers is clear. If someone uses their mobile phone, the aircrafts Hertzian waves may be interrupted and the communication between the pilot and the ATM tower might be unclear. During take-off and landing, there is a high level of communication taking place so an interruption is more serious. To ensure the safety of the passengers and aircraft, please be sure to turn off your mobile phone.