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

  • A Chinese relative of passengers aboard a missing Malaysia Airlines plane cries as she speaks to journalists aImage Credit: AP
  • A boy comforts a crying girl during a special prayer for the passengers of the missing Malaysia Airlines flighImage Credit: Reuters
  • In this Thursday, March 13, 2014 photo provided by China's Xinhua News Agency, China's rescue ships saImage Credit: AP

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.

Share your views.


    26-Mar-2014 07:45

    Meanwhile America was accusing Pakistan and its land that the plane hasbeen seen in Islamabad. OMG One should have sense that its a plane not abird which can be seen anywhere in the world. Secondly, I have alwaysbeen flying on different Airlines but indeed its dangerous and riskydoesn't matter which Airline. I have seen fear on the faces ofpassengers on Airports.

  • Mathew George

    23-Mar-2014 11:32

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

  • Dan

    22-Mar-2014 11:05

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

  • Yusuf Islam

    20-Mar-2014 15:35

    criticizing the pilots and other experts (flight engineer) who travel onboard without solid proofs is one of the cheapest thing to do it justadd more insult to injury for the family members who missing them andalso destroying their reputation and dedication ,hard work they did forlong a time for the airliner similar blame was imposed on the pilot ofsilk 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 plungedthe aircraft into the river for committing suicide but one of theinvestigating agency NTSB(National Transport Safety Board)concluded thecrash was defective servo valve inside the Power Control Unit (PCU)which controls the aircraft's rudder, causing a rudder hard-over and asubsequent uncontrollable crash. The manufacturer of the aircraft'srudder controls and the families later reached an out of courtsettlement. ....avoid much [negative] assumption. Indeed, someassumption is sin. And do not spy or backbite each other. Would one ofyou 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)

  • rizwan

    20-Mar-2014 12:35

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

  • Amir

    20-Mar-2014 12:30

    I have ONE serious Question, and I hope to see a response from anyTechnical, Aviation professional. My Question is, WHY such an importantpiece 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 turnedoff seems to be such a loop hole in Aviation Security. So to make it sosimple for any hijackers to enter into cockpit and turn of the switch tomake the airplane invisible to ground monitoring system. Howunbelievable it is... That switch should not even exist or should belocked while the plane is in flight.. I need an answer why it isavailable to be turned off during flight,.?

  • Leena

    20-Mar-2014 09:57

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

  • G K

    19-Mar-2014 21:48

    Could this be a cover up job, does the Malaysian government know thefact 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. Ijust pray that all the passengers, craft crew are safe or at least toget some sort of news as the relatives and friends of the victims mustbe getting insane by the amount of tension, confusion, hope,hopelessness. At least there should be a definite answer.

  • Shane

    19-Mar-2014 21:13

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

  • SAM

    19-Mar-2014 20:43

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

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Meanwhile America was accusing Pakistan and its land that the plane hasbeen seen in Islamabad. OMG One should have sense that its a plane not abird which can be seen anywhere in the world. Secondly, I have alwaysbeen flying on different Airlines but indeed its dangerous and riskydoesn't matter which Airline. I have seen fear on the faces ofpassengers on Airports.


26 March 2014 09:56jump to comments