A MH370 theory which claimed the doomed jet could not have sunk underwater because the victims' phones kept ringing after the crash has been debunked by experts.
The Malaysian Airlines jet vanished on March 8, 2014, en route to Beijing from Kuala Lumper killing 239 people on board – with officials believing it crashed into the sea.
One theory claims that because many relatives were able to hear a ringing tone for up to four days after the crash the doomed jet could not have smashed into the Indian Ocean.
However, wireless analysts claim that phone firms sometimes use a phantom ringing sound when the device is not active, the Daily Star reports.
The companies do this to keep callers on the line while the network tries to connect the call.
As a result, a ringing sound does not always mean the phone which is being called is still active.
Nineteen families have all claimed the devices of their loved ones rang for up to four days after the jet went missing.
One family member appeared on television in China and rang his dead brother’s phone to prove it was still ringing.
Indeed, telecommunications expert Paul Franks disagrees with the phantom ring tone theory insisting the aircraft could not have been submerged in water.
On Reddit, Franks wrote: “If the plane had crashed into the Indian Ocean, there is no way the phones would still ring.
“It’s not possible. As soon as a phone is submerged in water, especially sea water, it dies.
“Even if it were to survive, it would not get signal from the bottom of the ocean. All this shows the plane did not crash into the sea.”
What are the other theories behind MH370's disappearance?
A 449-page "final" report released in July by the Malaysian government only deepened the mystery – revealing that the plane’s sudden change in direction was a deliberate manoeuvre by somebody in the cockpit.
However what caused the Boeing 777 to divert 37 minutes remains a puzzle with most of the pieces missing.
What are some of the theories about the Malaysia Airlines flight?
Some feared Russian president Vladimir Putin was involved in the hijacking of MH370.
US Science writer Jeff Wise claimed Putin "spoofed" the plane's navigation data so it could fly unnoticed into Baikonur Cosmodrome so he could "hurt the West".
French ex-airline director Marc Dugain accused the US military of shooting down the plane because they feared it had been hijacked.
A book called Flight MH370 – The Mystery also suggested that it had been shot down accidentally by US-Thai joint jet fighters during a military exercise and covered it up.
Malaysia police chief Tan Sri Khalid Abu Bakar suggested the disappearance could have been the result of a suicide.
He claimed someone on board could have taken out a large life insurance package before getting on the plane, so they could treat their family or pay back the money they owed.
Historian and writer Norman Davies suggested MH370 could have been remotely hacked and flown to a secret location as a result of sensitive material being carried aboard the jet.
Cracks in the plane
Malaysia Airlines found a 15-inch crack in the fuselage of one of its planes, days before MH370 disappeared.
The Federal Aviation Administration insists it issued a final warning two days before the disappearance.
But the Daily Mirror claimed the missing jet "did not have the same antenna as the rest of the Boeing 777s" so it did not receive the warning.
Pilot planned the incident
Prime Minister Malcolm Turnbull unexpectedly said it was “very likely that the captain planned this shocking event”.
He claimed the pilot wanted to "create the world's greatest mystery".
Another theory claimed that he hijacked his own plane in protest of the jailing of then-Malaysian opposition leader Anwar Ibrahim, and as a way to destabilise the corrupt government of Najib Razak.
North Korea took the plane
In the wake of the incident, South Korea noted that North Korea nearly took out a Chinese plane which had 220 passengers on board, on March 5, 2014.
Some fear Pyongyang shot the plane down, but others believe it was hijacked and diverted into the communist nation.
Crashed in the Cambodian jungle
In September 2018, British video producer Ian Wilson claimed to have found the missing aircraft using Google Maps.
Despite millions being spent on the search to located the wreckage, the Brit sleuth believes he has found the jet in a mountainous area of the Cambodian jungle.
In response, the Chinese government used observation company Space View to focus in on the high-altitude area on the outskirts of Phnom Penh.
However, the firm claim there was no sign of any plane, least of all the Malaysian Airlines aircraft which has been missing since March 2014.