Planes shouldn’t just vanish. But that’s exactly what happened to a Boeing 777 on 8 March 2014. The true fate of Malaysia Airlines flight MH370 to Beijing, which left radar coverage less than two hours after take-off from Kuala Lumpur, is unknown.
No main wreckage has ever been found and neither have the bodies of the 239 passengers on the flight, despite the most expensive search in the history of aviation.
Theories about the plane’s disappearance abound, from a hijacking to a loss of oxygen in the cabin to a pilot gone rogue – yet no evidence of any technical failure, distress call or ransom demand has emerged in the years since MH370 disappeared.
Australian, Chinese and Malaysian authorities spent an estimated $130 million (£102m) trying to find MH370 before calling off the search in 2017. The world is still grappling with many unanswered questions about the ill-fated aircraft and the families of passengers travelling on it have had no closure.
But scientists haven’t given up. A decade on, some experts believe their research could shed new light on aviation’s biggest mystery and potentially reveal MH370’s final resting place.
Locating the main wreckage could help resolve outstanding uncertainties – not least, who was flying the plane when it disappeared.
One reason that such an extensive search has failed to turn up clues is that nobody knows exactly where to look for MH370, says Dr Usama Kadri, a mathematician at Cardiff University.
Official investigations showed MH370 deviated from its planned route to Beijing, instead heading southwest over the Indian Ocean. A measurement called burst-timing offset (BTO) helped experts estimate possible locations for the plane’s final destination.
While airborne, aeroplanes transmit automatic signals, known as ‘handshakes’, to satellites, and BTO is a measurement of how long these signals take to travel between plane and satellite.
Different BTO values can then be mapped out as a series of arcs on Earth’s surface, with each arc representing a range of BTO values and hence possible distances – much as wavelengths on the electromagnetic spectrum can be grouped into bands such as visible light, microwaves, X-rays and so on.
The last recorded ‘handshakes’ from MH370 were sent from somewhere within its seventh arc. Experts therefore concluded that MH370 should be found somewhere off the western coast of Australia. But the official targeted search area was huge, covering 120,000km2 (46,332 square miles) – around half the size of the UK.
Sound signatures
Narrowing the search window would boost the chances of finding the wreckage. Kadri believes underwater microphones, called hydrophones, could help provide clues as to where search teams should focus their efforts.
He analysed more than 100 hours of data from the Comprehensive Nuclear-Test-Ban Treaty Organisation’s (CTBTO) hydroacoustic stations, looking for signs of 10 historical aircraft accidents and one submarine disappearance.
To help find MH370, Kadri focused on data from stations at Cape Leeuwin in Western Australia and Diego Garcia, an island in the Indian Ocean. Both stations are located within tens of minutes’ signal travel from the seventh arc, and both were operational around the time MH370 is believed to have crashed.
Hydrophones are instruments that capture sound waves and pressure changes in the ocean. Violent ocean impacts such as plane crashes produce distinctive acoustic signatures. Hydrophones have previously detected signals from aircraft crashes, as well as earthquakes more than 5,000km (3,100 miles) away. “Sound can travel huge distances,” Kadri says.
A 200-tonne (220-ton) aircraft crashing at 720km/h (447mph) would release kinetic energy equivalent to that of a small earthquake, Kadri explains. Hydrophones are very sensitive, so it’s highly unlikely that an impact of this magnitude wouldn’t leave a detectable pressure signature.
The challenge, Kadri explains, is that “the ocean is a very noisy place” and there could be a lot of background noise from waves or marine life that obscures a signal from a plane crash.
“It’s not a question of ‘Is the sound being recorded?’” he says. “The question is: ‘Can we actually see that recording?’”
What matters as much as where MH370 crashed is how it crashed, Kadri adds. His work shows that violent plane crashes into the ocean are easier to detect in the acoustic data. If MH370 had made a softer landing in the ocean, it might not have generated a signal large enough to be seen in all the background noise.
This research builds on work undertaken by scientists at Australia’s Curtin University in the year MH370 disappeared.
The Australian researchers used hydrophone data to confirm a signal from an unknown source recorded at Cape Leeuwin station, coming from the direction of MH370’s seventh arc, the region where the plane is thought to have come down. But it fell outside the time window suggested by the official search team.
Kadri instead focused on that official time window and identified just one relevant signal, also recorded at Cape Leeuwin. But there was no trace of the signal at the Diego Garcia station. Kadri examined data along MH370’s initial flight path, too, but found no corresponding acoustic signatures.
Explosive investigations
While hydrophones could be a promising approach for detecting missing planes, Kadri was unable to find a signal with the certainty needed to launch a new search for MH370. The mystery remains unsolved for now, he admits. But explosions might help.
On 15 November 2017, the Argentinian submarine ARA San Juan carrying a crew of 44 went missing during a routine exercise. Experts at CTBTO stations noticed an unusual signal recorded by hydrophones a few hours later that could indicate an implosion.
The navy dropped grenades from the air at the submarine’s last-known location. The signal generated from these controlled explosions was similar to the unusual signal recorded a few hours after the submarine’s disappearance.
A year later, search teams discovered the wreckage of the San Juan just 20km (12 miles) from the anomaly identified in the CTBTO data. None of the 44 crew members survived.
Kadri’s theory is that experts could conduct similar explosion experiments for MH370 along the seventh arc.
“The basic idea is that we release the same amount of energy we believe has been released by MH370,” he says.
If the signals show similar pressure amplitudes, it would support future searches in that location. Conversely, if the signals are found to be unrelated, it might indicate that authorities should reassess the official time frame or location of the search window.
That said, explosions – even controlled ones – are expensive, require very specialised equipment and carry an environmental cost. This sort of research would therefore be likely to require approval from the Malaysian government, which Kadri acknowledges.
But, he argues, such experiments could help develop the use of hydroacoustic technology as a tool to narrow down potential search locations for plane crashes in the future.
Radio tripwires
Kadri’s not the only mathematician with an interest in finding MH370. At the University of Liverpool, Simon Maskell, a professor of autonomous systems, is looking at a different type of signal that could give us clues to the plane’s location.
Maskell and his team are analysing data from a technology called Weak Signal Propagation Reporter (WSPR, pronounced “whisper”). The WSPR network was set up in 2008 and involves amateur radio operators sending low-power test signals to receivers up to 10,000km (6,200 miles) away. These signals are stored in a huge database called WSPRnet.
“Think of WSPR like radio tripwires,” says Maskell. By this he means trying to determine if these tripwires fire more often when an aeroplane is present.
“Ideally if you were buying tripwires, you’d buy one that never fired when the aeroplane wasn’t there,” he says. The team now need to ascertain whether WSPR actually operates in this way and, therefore, whether it could be a useful tool for determining what happened to flight MH370.
Maskell is carrying out this work in collaboration with Richard Godfrey, a retired aerospace engineer who's been on an independent quest to locate MH370 for the last decade. Godfrey believes that MH370 would have generated anomalies in WSPR data after it went missing.
His theory is that an aircraft passing between the transmitter and receiver causes an increase in the rate at which disturbances are detected. Experts could then potentially use those anomalies to refine the search area for the missing plane.
Godfrey has pinpointed 130 disturbances in WSPR signals occurring over the southern Indian Ocean and reckons they could be evidence of MH370’s final flight path.
The disturbances terminate at a point just outside of the seventh arc, which could suggest search teams didn’t look quite far enough from the last point of communication between satellite and plane.
Godfrey believes that one final search would be enough to find the missing aircraft and solve the world’s biggest aviation mystery. Not everyone is convinced, though – so Maskell is using statistical tools to determine if there’s weight to Godfrey’s hypothesis.
“Richard is strongly of the opinion that WSPR contains information pertinent to the location of MH370,” Maskell says. “And there are other people that are firmly of the opinion that it doesn’t. So we’re trying to figure out who’s right.”
The Liverpool team is analysing other Boeing 777 flights with known trajectories and comparing the associated WSPR data.
Maskell and co are conducting research at a far greater scale than Godfrey has attempted to date, so the hope is that their analysis will soon show us whether or not WSPR can provide useful information in the case of disappearing aircraft, and potentially help define a new search area for MH370.
A natural solution
Other researchers seeking to find MH370 are putting their hopes in sticky little marine crustaceans. Although we haven’t found MH370’s main wreckage yet, a large piece of debris called a flaperon (the moving part of a plane wing) washed up on a beach in Saint-Denis on Réunion Island in the western Indian Ocean in late July 2015. Experts later confirmed that it belonged to MH370.
“The flaperon was covered in barnacles and as soon as I saw that, I immediately began sending emails to the search investigators because I knew the geochemistry of their shells could provide clues to the crash location,” Gregory Herbert, a geoscientist at the University of South Florida, said in a statement in August 2023.
Barnacles grow their shells daily, producing internal layers that look a bit like tree rings. The chemistry of each layer is determined by the temperature of the surrounding water at the time that layer was formed.
Because ocean temperatures in the region where MH370 is thought to have disappeared can change rapidly, some researchers believe that barnacles could help reveal where the plane might be.
The largest barnacles might be old enough to have colonised the wreckage shortly after the crash. Determining the temperatures recorded in the shells of the biggest barnacles on MH370’s debris could, it’s hoped, lead search teams to the right spot.
Whatever technique eventually gets us to MH370, finding the wreckage could provide the answers families have been desperately seeking for many years. Solving the mystery could also teach the aviation industry lessons about making air travel safer in the future.
From 2025, the international Civil Aviation Organization will mandate that planes carry a device that broadcasts their position every minute if they encounter trouble. But finding out what really happened to MH370 could lead to even more robust measures.
Even 10 years on, the deep, dark, cold conditions of the ocean are ideal for preserving evidence, so it’s likely the wreckage will have a lot to tell us when it’s uncovered.
The hunt resumes
Ocean Infinity, a marine robotics company based in Texas, has announced its intention to restart the search for the missing aircraft. The firm previously launched an independent hunt for the plane after the official one was called off in 2017, but abandoned it a year later.
“Finding MH370 and bringing some resolution for all connected with the loss of the aircraft has been a constant in our minds since we left the southern Indian Ocean in 2018,” said CEO Oliver Plunkett in a statement.
“We’ve been working with many experts to continue analysing the data in the hope of narrowing the search area down to one in which success becomes potentially achievable. We hope to get back to the search soon.”
The company says it has spent the past few years focusing on developing advanced robotic technology to enhance its ocean search capabilities. It has submitted a proposal to the Malaysian government to resume the search on a no-find, no-fee basis.
But it’s not yet clear if authorities will approve a new mission: Malaysia has consistently said it would only re-open the search in the face of credible new evidence.
Maskell is certain we won’t be left in the dark about what happened to MH370 forever, though. “At some point, someone will be surveying the bottom of the ocean and say ‘Hey, look, MH370!’” he says.
“I think the tougher question is whether we’re going to find it in the next year. That requires a whole load of political decisions.”
About our experts
Dr Usama Kadri is a mathematician at Cardiff University. His research focuses on fluid dynamics and nonlinear phenomena.
Simon Maskell is a professor of autonomous systems at the University of Liverpool. His research interests are focuses on developing algorithmic solutions for a variety of industries.
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