How is the plane tracked?

Thanks to the signal relay or global positioning system, the journey of an aircraft will be monitored and controlled, but it cannot exclude the possibility that they encounter some unexpected problems.

What is a relay?

Air traffic control incorporates parameters that determine the position of the basic radar with signals provided by the transponders (receive and receive signals) of the aircraft, to create a detailed picture of the delivery air cargo

Location of black box and relay system on an aircraft.(Photo: BBC)

All commercial aircraft are equipped with transponders in the cockpit area. The relay will automatically transmit the electronic signal to the ground when receiving a radio signal.

The most basic types of relay systems usually only send signal to altitude and plane code. However, radar stations can still determine the speed and flight direction of an aircraft by checking the transmission process.

The radar coverage area usually spans about 240km from the coast. When flying over the sea, the crew kept in touch with the ground control and other planes using high-frequency radios.

The relay can be turned off manually when the aircraft is in the air. However, in the case of the MH370, the cause of signal loss due to human intentional action or the impact of a severe weather phenomenon is still a mystery.

"Okay, obviously" is the last radio signal that the air traffic control unit shows that everything is normal until the plane completely disappears.

Diagram simulating the process of receiving signals and signaling from air traffic control stations and aircraft.(Photo: BBC)

What happens if the relay does not work?

When the transponder stops sending signals, the aircraft can still be monitored using a similar method to radar detection developed in the 1930s.

The primary radar system that performs monitoring and reviewing everything in the sky may indicate that the radio signal is still transmitted. So radar can only indicate the relative position of an aircraft without being able to identify it. Today, this method is mainly used as a support system for secondary radar.

According to Malaysian officials, primary radar tracking of the aircraft could provide information about the journey of the missing plane. However, these data need to be analyzed in detail by experts.

Global positioning system

Actual aircraft can be equipped with global positioning system (GPS) . Meanwhile, the world's air traffic control network is still almost entirely based on the operation of the radar system.

With GPS, pilots can determine the location of the aircraft on the map. This data is not currently provided to air traffic control.

Some of the most modern aircraft in the world can reverse GPS data with satellite tracking centers. However, processing a large amount of data will be very costly and these systems are usually only used in remote areas without radar coverage.

Aviation expert Chris Yates said the automatic monitoring system - broadcast broadcast (ADS-B) , new technology in air traffic monitoring and management, is using GPS data in its operations. plane tracking.

ADS-B will operate systems that provide "fake radar" images of aircraft in flight. These images will be used by online search agencies and included in the mapping system.

The aircraft uses the ADS-B system to locate via a satellite, then broadcast the location signal to another aircraft and to the ground station.

In the US, all aircraft are required to equip the ADS-B system from now until January 2020,. This system is expected to replace future radar-based aircraft search operations.

The Malaysia Airlines aircraft no longer appears on the aircraft tracking website at the same time it disappears from the air traffic control screen and no GPS data has been recorded so it can be found.

A fragment from the Air France aircraft 417 was found in the Atlantic Ocean.(Photo: AP)

ACARS system

When the Air France 447 plane crashed into the Atlantic in 2009, the Reporting and Communication System (ACARS) helped investigators find clues about what happened to the aircraft.

Thanks to the ACARS system , aircraft computers can communicate with the computer on the ground and provide information about the operating status of the system on the fly. Messages will be transmitted by radio signals or electronic signals via satellite and may cover many issues related to the status of the aircraft, from engine engines to restrooms. Important information will be sent to the ground monitoring department and the support process will be carried out more quickly.

Thanks to ACARS, experts discovered the speed control of Air France aircraft in the 2009 incident. This was the cause of the crew's disorientation and the plane crashed a few minutes later.

However, in the case of the missing plane of Malaysia Airlines, investigators said no relevant data has been recorded so far.

Data recorded in the black box can help find the cause of the plane crash.(Artwork: NTSB)

Black box

According to aviation experts, the mysterious disappearance of MH370 can only be explained when the data recorded in the black box of the machine is restored. However, in case the plane falls into the sea, recovering this data is not easy.

When underwater, the black box will spontaneously provide ultrasound signals. However, these signals are only detected at a narrow range. Search teams can only detect this signal if approached close enough to the location of the plane in distress.

Black boxes are not equipped with GPS positioning devices, so finding it often makes it difficult for rescue teams.