It seems impossible in such a technologically advanced era for an airplane to seemingly vanish in midair. The disappearance of Malaysia Airlines MH370 on March 8, 2014, has lead to numerous search attempts involving a variety of technologies.
Radar is the primary tool for tracking passenger flights. There are different types that can be used by air traffic control to identify planes over land. Primary radar detects objects by bouncing back radio signals, while secondary radar involves the plane automatically sending responses to identify itself. In primary radar, even if the plane is not in communication with ground control its location can still be tracked. These signals do not communicate with the plane.
With secondary radar, periodic query signals are sent to the plane and answers are received back to verify location, identity and altitude. It is an automatic radar system that can be turned off or disabled if there is a loss of power. In the case of the Malaysia Airlines flight, it was being tracked by secondary radar over the South China Sea when it disappeared from monitors.
Searching such vast areas and depths in the ocean requires some high-end technology. Planes carry an underwater locator beacon or pinger, which transmits an ultrasonic pulse from the cockpit voice recorder and flight data recorder with a varying range of 3 to 20 kilometers away depending on the device. Pingers become triggered when immersed in water. A device called a towed pinger locator can dive to 20 000 feet below the ocean surface travelling at 2 to 9km/h for hours at a time to search for the pulse from this beacon. Dragged behind a ship, this technology was used in the earlier stages of the search because the batteries powering the ping from the plane only lasts 30 to 40 days and can be drowned out completely under certain ocean conditions.
Autonomous underwater vehicles or AUVs are usually used in the oil and gas industry to survey oilfields. However, when the pinger of the black box is dead, an AUV can map the ocean floor and narrow down the search for the crash site of the plane. One of the most sophisticated AUVs was flown to Perth, Australia to help with the search for MH370. It can be lowered to 20 000 feet and travel at a speed between 3 to 8km/h for about 20 hours. Using a side-scan sonar it can create a 3D map of the seafloor. AUVs are unmanned and can be programmed to use a grid style pattern to create an image of the deep sea.
Using sonar technology the investigation of the floor of the Indian Ocean has unraveled the secrets of parts of the seabed that have never been discovered before, including a 1.5 km canyon and extinct volcanoes spread out across the ocean floor. The Australian Transport Safety Bureau is mapping the approximately 60 000 square kilometer area most likely to contain the remains of the plane where pings thought to be from the black box were detected earlier in the investigation.
The mapping of the underwater topography is key for the next stage of the search, which includes multiple pieces of search equipment towed just above the sea floor for a more detailed search for debris. The information gathered will help ensure safety and avoid any unexpected obstacles for the equipment to collide into. Although 72% of Earth is covered in water, the majority of it has yet to be explored because of the depths and conditions of the oceans. Technologies like radar and satellites are only good for building maps of Earth’s surface, unable to penetrate the seawater. Therefore sound has to be used to do the mapping underwater and it is a slow and tedious process.
Not only is the 3D map being generated by sonar aiding with the search but it may also provide scientists and meteorologists with a better forecast for tsunamis. Tsunamis have proved to be one of the deadliest natural disasters, and detailed models of the ocean terrain could help save many lives. A greater understanding of the ocean can also be valuable for geological interpretation purposes including plate tectonics, analysis of unusual sea floor features, and a better understanding of ocean currents and the climate.
The fact that the incident occurred over the ocean means that it could be years before we know exactly what went wrong. Finding clues in such a vast area is slow. It took two years for investigators to recover the black box recorder from the Air France 447 flight. With the Australian Transport Safety Board recently predicting that the wreckage is most likely to wash up on the Indonesian coast, we can only hope that answers will be found soon.
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