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Why didn't missing Malaysian jet passengers use their cell phones?

It may indicate that the plane was flying too high or was over water, or that the passengers were unconscious

  • AFP
  • Published: 14:35 March 19, 2014

  • Image Credit: AP
  • A Chinese relative of passengers aboard a missing Malaysia Airlines plane cries as she speaks to journalists at a hotel in Sepang, Malaysia, Wednesday, March 19, 2014.
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BANGKOK: In the age of smartphones and social media, one question surrounding the disappearance of the Malaysian airliner is why none of the passengers tried to contact relatives, as they did during the 9/11 attacks.

Even the absence of phone calls or emails from those on board the Malaysia Airlines Boeing 777 could provide clues for investigators struggling to solve one of the greatest mysteries of modern aviation.

It may indicate that the plane was flying too high or was over water, or that the passengers were unconscious, possibly due to a change in cabin pressure.

Experts say the chances of the 239 people on board Flight 370 being able to use their mobile devices would have been better the closer they were to a mobile network on the ground.

Many are sceptical that the passengers or crew would have been able to establish and maintain a call using cellphones while travelling at speed, particularly at cruising altitude.

For mobile phones to be used, there must be a contact between the handset and the network - known as a "handshake". This requires a strong enough signal from both a transmission tower and the phone.

"Theoretically, 23,000 feet (7,000 metres) and 45,000 feet are a cell range that terrestrial mobile network could work with," said Singapore-based telecommunications consultant Koh Chee Koon, referring to unconfirmed reports of changes in the plane's altitude after it lost radar contact.

But given the limited transmission power of a commercial mobile phone, as well as the barrier presented by the plane body, "for the mobile phone to connect to the mobile network with acceptable strength and quality would require some luck", added Koh.

Experts note that in the case of the September 11, 2001 attacks in the United States, the planes were flying at relatively low altitude over areas with cellphone coverage.

In any case most of the calls are believed to have been made from seatback phones and not mobile devices.

Recently some airlines have introduced technology to enable passengers to use their phones in the air using a small cellular base station on board, but Malaysia Airlines said this service was not available on Flight 370.

Without this, a cellphone cannot be used at an altitude of more than roughly 0.5 kilometres in the case of a commercial airliner, and must not be too far from a cell tower, according to A.K. Dewdney, professor emeritus of computer science at the University of Western Ontario in Canada.

"No cellphone could possibly succeed from an airliner in mid-ocean, even if flying low over the water," he said.

"At normal cruising altitude no cellphone could possibly succeed in making ground contact as it is completely out of reach of the network of towers, in any case," added Dewdney, who conducted experiments after the 9/11 attacks to test the capability of mobile telephones to make calls from the air.

 

Phone records under investigation


Malaysia Airline chief executive Ahmad Jauhari Yahya said on Monday there was no evidence of any attempt by the people on board to make calls, but he added that "millions of records" needed to be processed.

"It's being done as part of the investigation," he said, without elaborating on the type of records being checked.

Deepening the mystery, Chinese media have reported that relatives heard ringing tones when trying to call passengers' mobile phones.
But experts believe this does not necessarily mean the phones were still functioning.

Even if nobody on board the plane tried to make a call, logs of the "handshakes" might provide some clues about the route taken by the jet after it disappeared.

While many phones would have been switched off in line with airline rules, some people may have forgotten to deactivate their devices.
But to trace any "handshakes" investigators face the challenge of collecting the unique identity numbers for the passengers' mobile devices, as well as signal data from network operators in countries along the possible flight paths, such as Myanmar which still has limited network coverage.

As the flight turned back and crossed over Malaysia after disappearing from radar en route to Beijing, it probably passed over a network area.

After that, the chances of any "handshakes" depend on how low and close to mobile towers the plane flew.

"Police track cellphones all the time by the last phone call they made," said Ken Dulaney, a US-based analyst with technology research firm Gartner.

But he added that this was only possible if the devices were in reach of a network.

"If they are not in coverage then no one can do anything," he said.

Comments (49)

Share your views.
  1. Added 07:45 March 26, 2014

    Meanwhile America was accusing Pakistan and its land that the plane has been seen in Islamabad. OMG One should have sense that its a plane not a bird which can be seen anywhere in the world. Secondly, I have always been flying on different Airlines but indeed its dangerous and risky doesn't matter which Airline. I have seen fear on the faces of passengers on Airports.

    MUSHAID, ABUDHABI, United Arab Emirates

  2. Added 11:32 March 23, 2014

    This is not 1900's but 2014 where everyone knows about so many satellites orbiting the earth..are you telling me that not one of those satellites could record what exaclty happened to that plane from space????

    Mathew George, Muscat, Oman

  3. Added 11:05 March 22, 2014

    Lets not compare this to 911 passenges using cellphones as that incident is widely disputed now to have been fake phone calls and not even an actually loaded plane. The crash site was a joke showing no engines, seats, clothing or other things a loaded jet would scatter on impact(that plane did no more disintegrate then the World Trade Centers collapsed from heat stressed steel--number 7 was not even hit). No, cellphones not used as they dont transmit from such heights especially from a metal skinned plane and also because passnegers as one pserson said, likely didn't know anything was wrong, ezpecially if hijacked to land somewhere.

    Dan, Canada, Canada

  4. Added 15:35 March 20, 2014

    criticizing the pilots and other experts (flight engineer) who travel on board without solid proofs is one of the cheapest thing to do it just add more insult to injury for the family members who missing them and also destroying their reputation and dedication ,hard work they did for long a time for the airliner similar blame was imposed on the pilot of silk Air flight 185 in the year of 1997 that they said the captain Mr. Tsu Way Ming who was a former A-4 Skyhawk pilot,was delibratey plunged the aircraft into the river for committing suicide but one of the investigating agency NTSB(National Transport Safety Board)concluded the crash was defective servo valve inside the Power Control Unit (PCU) which controls the aircraft's rudder, causing a rudder hard-over and a subsequent uncontrollable crash. The manufacturer of the aircraft's rudder controls and the families later reached an out of court settlement. ....avoid much [negative] assumption. Indeed, some assumption is sin. And do not spy or backbite each other. Would one of you like to eat the flesh of his brother when dead? You would detest it. And fear God ; indeed, God is Accepting of repentance and Merciful. (Al-Qur'an 49:12)

    Yusuf Islam, Dubai, United Arab Emirates

  5. Added 12:35 March 20, 2014

    today in the most advance technologies and with the high tech 777. how can we expect that all the controls were in the hands of pilots. there should be some ways to control the plane from ground. why information system is in total control of pilots solely. any communication inside the cabin must transmit live to the ground station and should be recorded. its a matter of precious lives. these are the questions that my mind raises when i m needed to fly.. could this happen with us also...?

    rizwan, ruwais, United Arab Emirates

  6. Added 12:30 March 20, 2014

    I have ONE serious Question, and I hope to see a response from any Technical, Aviation professional. My Question is, WHY such an important piece of equipment switch is even available to switch off during flight? The transponder that sends signal to the ground about its speed, altitude, location has a switch in the cockpit available to be turned off seems to be such a loop hole in Aviation Security. So to make it so simple for any hijackers to enter into cockpit and turn of the switch to make the airplane invisible to ground monitoring system. How unbelievable it is... That switch should not even exist or should be locked while the plane is in flight.. I need an answer why it is available to be turned off during flight,.?

    Amir, Abu Dhabi, United Arab Emirates

  7. Added 09:57 March 20, 2014

    what if a person from any witness protection plan was in the aircraft...and the people who wanted the aircraft down was targetting them!!

    Leena, Abu Dhabi, United Arab Emirates

  8. Added 21:48 March 19, 2014

    Could this be a cover up job, does the Malaysian government know the fact and now is hiding and misleading the world by this story and that? could be possible, yes. It can not be untraceable like this, sorry. I just pray that all the passengers, craft crew are safe or at least to get some sort of news as the relatives and friends of the victims must be getting insane by the amount of tension, confusion, hope, hopelessness. At least there should be a definite answer.

    G K, dubai, United Arab Emirates

  9. Added 21:13 March 19, 2014

    On all planes with seat TV screens you can see the flight info that shows the flight path, altitude, speed and time to destination etc. Could the passengers been able to see this information or would have this feature been disabled when the transponder was switched off or could have the pilot switched off the TV screens from the cockpit?

    Shane, Dubai, United Arab Emirates

  10. Added 20:43 March 19, 2014

    If NASA can trace signals beyond our solar system & are trying to decode them, why search of 370 taking such a duration??

    SAM, DXB, United Arab Emirates

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