Endless theories are swirling about what became of Flight MH370. Was it hijacked by fanatics, led into unknown territory by Vietnamese MiGs, or did one of the pilots simply decide to end it all?
And questions abound as to why it seems that passengers’ phones still seem to be ringing, why radar was unable to track it, and why search parties have been unable to locate its black box signal.
Here, the Mail offers answers to the questions everyone’s asking…
![The search continues: A helicopter crewman from Singapore's Navy uses binoculars to scour the ocean in the hunt for missing Malaysian Airlines flight MH370, which has vanished without a trace](https://i.dailymail.co.uk/i/pix/2014/03/12/article-2578803-1C36139000000578-68_634x423.jpg)
The search continues: A helicopter crewman from Singapore’s Navy uses binoculars to scour the ocean in the hunt for missing Malaysian Airlines flight MH370, which has vanished without a trace.
![Hunt: Two Singapore Navy sailors look at at the featureless sea during the search in this picture released today](https://i.dailymail.co.uk/i/pix/2014/03/12/article-2578803-1C36139400000578-55_634x423.jpg)
Hunt: Two Singapore Navy sailors look at at the featureless sea during the search in this picture released today.
1. How could there be reports from relatives that some of the passengers’ phones are still ringing?
If the phones are ringing, that could mean they are on land and near a mobile cell site. If that is the case, it seems bizarre nobody noticed the plane land or crash.
However, experts doubt the phones are ringing. If you call someone whose phone has no charge, it sounds as though the phone is ringing, before you go through to the voicemail.
‘The phones definitely won’t be working,’ says Professor William Webb, a Fellow of the Royal Academy of Engineering.
‘They will be underwater, out of coverage and by this time out of battery.’
![Military officials inside a Soviet-made AN-26 of the Vietnam Air Force during the search and rescue operations for the missing Malaysia Airlines flight](https://i.dailymail.co.uk/i/pix/2014/03/11/article-2578199-1C2EEC0300000578-876_634x423.jpg)
Military officials inside a Soviet-made AN-26 of the Vietnam Air Force during the search and rescue operations for the missing Malaysia Airlines flight.
![A military source has said the plane was tracked over the Strait of Malacca. Pictured are staff members at the rescue command office for the missing flight](https://i.dailymail.co.uk/i/pix/2014/03/11/article-2578199-1C2F0B3800000578-793_634x422.jpg)
A military source has said the plane was tracked over the Strait of Malacca. Pictured are staff members at the rescue command office for the missing flight.
2. One theory says the plane was escorted to a secret location by Vietnamese fighter jets. Could that happen?
The Boeing 777 is a large aeroplane – 242ft long, with a 200ft wingspan. It’s difficult for an aircraft of that size to land somewhere unusual without people spotting it.
‘A 777 needs a runway that is a good 2,000m (2,180 yards) long,’ says Robin Durie, an experienced commercial pilot.
‘You don’t just land a plane like that in a clearing in the jungle.’
![Fears: The relative of a passenger aboard Malaysia Airlines Flight MH370 weeps as she is surrounded by reporters at Metro Park Lido Hotel in Beijing, China](https://i.dailymail.co.uk/i/pix/2014/03/12/article-2578803-1C29DAD900000578-287_634x451.jpg)
Fears: The relative of a passenger aboard Malaysia Airlines Flight MH370 weeps as she is surrounded by reporters at Metro Park Lido Hotel in Beijing, China.
![Worry: The relatives of another passenger wait for updated information regarding the missing aircraft at a hotel in Putrajaya in Kuala Lumpur, Malaysia](https://i.dailymail.co.uk/i/pix/2014/03/12/article-2578803-1C29B09600000578-860_634x490.jpg)
Worry: The relatives of another passenger wait for updated information regarding the missing aircraft at a hotel in Putrajaya in Kuala Lumpur, Malaysia.
3. Why is the ‘black box’ not revealing the plane’s location?
The black box, or flight data recorder, stores much of the information about the flight, including the conversations of the pilots.
The boxes are almost indestructible, and resilient to impact and heat.
After a plane has crashed, the black box transmits a homing beacon, but the range is only 2,000 or 3,000 yards, and even less if it is deep underwater.
‘A device such as a black box doesn’t make the aircraft safer,’ says Mr Durie. ‘They just tell you where its wreckage is. But airlines are very reluctant to add numerous pieces of technology, as they are expensive to buy and maintain.’
There has recently been discussion within the industry about the possibility of sending data from aircraft during their flights to a remote server, thereby negating the need for a black box, but this is regarded as being too expensive.
![A U.S. Navy SH-60R Seahawk helicopter takes off from the destroyer USS Pinckney in the Gulf of Thailand, to assist in the search for missing Malaysian Airlines flight MH370](https://i.dailymail.co.uk/i/pix/2014/03/12/article-2578803-1C338A4400000578-490_634x417.jpg)
A U.S. Navy SH-60R Seahawk helicopter takes off from the destroyer USS Pinckney in the Gulf of Thailand, to assist in the search for missing Malaysian Airlines flight MH370.
4. Why can no debris or wreckage be found? It seems inconceivable that an aircraft of this size could leave no trace.
‘I find that very odd as well,’ says Mr Durie. ‘Aeroplanes are not just made from metal, and there are lots of parts of them, such as seats and luggage, that can float.
‘Even after the Air France crash over the Atlantic in June 2009, a whole piece of rudder was found on the water.’
However, Mr Durie also cites the example of the 2005 crash of Helios Airways Flight 522, which flew on its own for almost three hours after the crew members were incapacitated by a lack of oxygen. It crashed near Athens, killing all on board.
With several hours of fuel, it is possible that MH370 crashed hundreds of miles away from its last known location.
![How could it just disappear? Members of the Chinese emergency response team on 'South China Sea Rescue 101' carry out search mission at the possible crash site of missing Malaysia Airlines flight MH370](https://i.dailymail.co.uk/i/pix/2014/03/12/article-2578803-1C2F800C00000578-516_634x419.jpg)
How could it just disappear? Members of the Chinese emergency response team on ‘South China Sea Rescue 101’ carry out search mission at the possible crash site of missing Malaysia Airlines flight MH370.
![Chinese rescue teams salvage possible floating objects from the waters as they hunt for traces of MH370](https://i.dailymail.co.uk/i/pix/2014/03/12/article-2578803-1C2F800600000578-958_634x421.jpg)
Chinese rescue teams salvage possible floating objects from the waters as they hunt for traces of MH370.
5. Are there areas of the world where a plane can just ‘slip off the radar’?
Plenty. Tracts of Africa, much of the interior of Russia, jungles in Malaysia, for example.
Modern airliners use transponders, which transmit a unique four-digit code that is identified with the flight. It is these codes that are picked up by air traffic controllers and used to locate the aircraft.
If the transponder stops transmitting – either because it is turned off or as the result of a sudden, catastrophic incident – then over many parts of the globe, the plane would be invisible to air traffic controllers.
![An Indonesian Navy pilot conducts an aerial search for the missing flight](https://i.dailymail.co.uk/i/pix/2014/03/12/article-2578803-1C2ABFF800000578-627_634x413.jpg)
An Indonesian Navy pilot conducts an aerial search for the missing flight.
6. Why was no distress signal sent?
‘If you have some form of emergency, then the first thing the pilot does is to change the transponder code,’ says Mr Durie. ‘If you change your code to 7500, that means you have been hijacked.
‘Back at Air Traffic Control, a big red box appears around your flight, and people take notice very quickly.’
In the event of a serious malfunction, the code changes to 7600, and in a Mayday situation, to 7700.
Changing the code is as quick as entering your PIN on a cash machine.
‘The fact that the transponder code didn’t change suggests to me that whatever happened, happened really quickly,’ says Mr Durie. ‘This might mean an explosion.’
![Vietnam Air Force Deputy Commander General Do Minh Tuan looking out from the door of a Russian-made MI-171 helicopter during a search flight some 200km off the southern Vietnamese waters](https://i.dailymail.co.uk/i/pix/2014/03/12/article-2578803-1C2F9BD200000578-567_634x423.jpg)
+17
Vietnam Air Force Deputy Commander General Do Minh Tuan looking out from the door of a Russian-made MI-171 helicopter during a search flight some 200km off the southern Vietnamese waters
![Where next? A Vietnamese Air Force navigator checks a map during the search flight close to Phu Quoc island](https://i.dailymail.co.uk/i/pix/2014/03/12/article-2578803-1C2F8D1F00000578-794_634x420.jpg)
7. A pilot on another aircraft claims to have made contact with MH370 shortly before it went missing – but all he heard was mumbling. What could this mean?
‘All pilots have frequencies that we use to chat on,’ says Mr Durie. ‘Often this is company traffic, when crew from the same carrier are simply talking to each other.
‘Technically, it’s not legal, but the practice is widespread and many pilots tune into the easy-to-remember VHF band of 123.45.’
If another pilot heard some mumbling, it is possible that it was chat coming from another pilot on the same frequency. However, it could have been a crew member from MH370.
‘The mumbling suggests to me that the pilot was passing out from a lack of oxygen,’ says Mr Durie, ‘which could mean that the aircraft had suffered an explosive decompression, such as a window popping out, or a small hole appearing in the fuselage.’
![Vigil: Chinese students hold candles while praying for the passengers aboard the missing Boeing 777](https://i.dailymail.co.uk/i/pix/2014/03/12/article-2578803-1C2A889100000578-838_634x434.jpg)
Vigil: Chinese students hold candles while praying for the passengers aboard the missing Boeing 777.
8. Would it be possible for a deranged or psychotic passenger to seize control and cause a disaster?
The door to the cockpit is locked, and can be opened only from the inside. However, large airliners carry an axe in a secret location in one of the galleys.
A fanatic who found the axe could break into the cockpit, but it is unlikely the axe could be found without the knowledge of the cabin crew.
![Sombre: A relative of a missing passenger waits for news at a hotel in Putrajaya, Malaysia](https://i.dailymail.co.uk/i/pix/2014/03/12/article-2578803-1C2999F000000578-609_634x422.jpg)
Sombre: A relative of a missing passenger waits for news at a hotel in Putrajaya, Malaysia.
![Tough time: More relatives of missing passengers are photographed in a car outside the Kuala Lumpur hotel](https://i.dailymail.co.uk/i/pix/2014/03/12/article-2578803-1C2EB2FD00000578-842_634x436.jpg)
Tough time: More relatives of missing passengers are photographed in a car outside the Kuala Lumpur hotel.
9. Could the pilot have hijacked or deliberately crashed the aircraft?
Pilots have been known to hijack their own planes. One theory behind the crash of EgyptAir Flight 990 into the Atlantic in 1999 is that the Relief First Officer wanted to commit suicide.
‘A pilot can turn off his transponder, thereby making his plane invisible to Air Traffic Control,’ says Mr Durie.
‘Then, if he takes control of the cockpit, he can fly where he wants – either somewhere to seek asylum, or horribly, to kill himself and all on board.’
![Mystery: An aerial view of what is believed to be an oil slick taken from a Vietnamese Air Force plane during search and rescue operations](https://i.dailymail.co.uk/i/pix/2014/03/12/article-2578803-1C2A065900000578-776_634x411.jpg)
Mystery: An aerial view of what is believed to be an oil slick taken from a Vietnamese Air Force plane during search and rescue operations
10. Reports suggest that radar showed the aircraft descending rapidly and possibly turning before it disappeared. Can a pilot simply turn around in the event of problems?
In theory, pilots are not permitted to simply turn their aircraft around. The globe is criss-crossed with air routes, which are like motorways, and are strictly policed by Air Traffic Control.
However, in the event of an emergency, a pilot is entitled to change direction, especially if he is losing altitude and threatening to cross through other routes beneath him.
Mr Durie said: ‘The usual procedure is to turn 90 degrees, and to get out of the airway – almost like pulling on to the hard shoulder – and to inform Air Traffic Control that you are in jeopardy.’
![Do Minh Tuan, deputy commander of the Vietnamese Air Force looks at a Google Maps image on a TV screen during a news conference about their mission to find the missing jet. U.S. spy satellites could not find it either](https://i.dailymail.co.uk/i/pix/2014/03/12/article-2578803-1C2EB12600000578-799_634x423.jpg)
Do Minh Tuan, deputy commander of the Vietnamese Air Force looks at a Google Maps image on a TV screen during a news conference about their mission to find the missing jet. U.S. spy satellites could not find it either.
11. If the flight was downed by an explosion, why wasn’t it captured on film by a US satellite?
Not even the United States has the capability to record what happens everywhere in the world all the time.
If the plane did explode, then it is perfectly possible that the event would not have been captured by satellite.