Smartphone sensors could yield airplane accident clues
Almost nine weeks on, the search for flight MH370 has come up with nothing. A robotic sonar-carrying submarine is now searching the seabed 2000 kilometres off Perth, Australia, but after scanning 314 square kilometres, there is still no sign of the jet.
The only hope investigators have of finding out what happened is to find the flight data recorders – often called the black boxes. But what if they have been destroyed or sunk to depths of the southern Indian Ocean that rescue teams cannot reach?
Black box alernative
There may be an alternative. If the wreckage is found, sensors and apps running on passengers’ smartphones could help work out what happened to the flight.
While lithium batteries wouldn’t survive being under water, forensics experts can tease apart microchips and, if necessary, use scanning electron microscopes to probe the data stored in components like solid state memory chips. Indeed, some groups, such as the French air accident investigator BEA, already employ this technology.
For example, earlier this month digital forensics firm 4Discovery of Chicago, Illinois placed a smartphone in a high pressure saltwater chamber at Chicago’s Shedd Aquarium. After a week of immersion, memory chips recovered from the ruined phone by Gillware Data Recovery of Madison, Wisconsin, revealed email, texts, photos and video data hadn’t been lost.
Even the more ordinary functions of phones – audio, picture and video capture – can reveal key accident information. An example was tragically witnessed this week when rescuers retrieved a smartphone from the body of a student who drowned in the 16 April ferry sinking off Jindo, South Korea. A video file on the phone’s memory card could potentially prove what the authorities told the passengers to do as the ship began to sink.
But it is the increasingly sophisticated array of sensors appearing on phones that may make them ever more useful in accident analysis. If a plane’s black boxes are lost or destroyed, the data found in crew or passenger phones might give investigators clues about the history of its airspeed, its direction of flight, its orientation in space and even its cabin air pressure.
Motion, orientation, position
That is because smartphones contain accelerometers that sense motion, gyroscopes that detect orientation, GPS position receivers, and some phones – currently only the Samsung S4 and S5 – even have air pressure sensors, intended to measure altitude for climbers and skydivers.
Magnetometers – which provide positioning information by measuring Earth’s local magnetic field – plus temperature and humidity sensors are beginning to appear in them, too.
Sampo Karjalainen, CEO of the Finnish firm Protogeo that created an activity tracking app called Moves, bought by Facebook last week, says the way apps log data could be useful to investigators. For example, acceleration and gyroscope data is collected by the iPhone 5s even when the main processor is asleep. “That data is then available when an app wants it,” he says.
“So sensing turns of an aircraft, or changes in g-forces, might be doable as these sensors start to collect continuous data. Wearables like wristbands and Google Glass are perfect for this continuous analysis, too,” says Karjalainen.
Chris Hargreaves of the Centre for Forensic Computing and Security in Bedfordshire, UK, thinks using phones in air crash forensics sounds feasible
“I can certainly imagine that some data from mobile and wearable devices could be relevant to an aircraft investigation,” he says. “Digital forensics is not just for cybercrimes but murders, kidnappings and burglaries too – so why not as part of aircraft investigations?”
Simon Steggles, a director of cellphone forensics firm Disklabs in Tamworth, UK, analyses cellphones for the police. He agrees there is a chance that some useful data may be left in a phone’s memory if a passenger on a downed aircraft had been using an app. “If so, there is a good chance we could get something out of it, but we wouldn’t know until it is actually here in our labs as all apps behave differently,” he says.
In-flight gadgets are already used as forensic tools for light aircraft, says Matthew Greaves, head of safety and accident investigation at one of the UK’s major aeronautics schools, Cranfield University near Bedford. “Investigators regularly extract what they can from iPads, helmet cams and even GPS units that weren’t being used. These often record data in the background that is never displayed to the user and can be recovered after an accident.”
One problem he foresees is that smartphones are not certified for the accuracy required in aviation. “With any sensor, its accuracy and how its measurements drift and cope with interference are the issues,” he says. He suspects phones are not up to scratch in that regard, and useful data may be minimal.
However, Greaves says there is a salutary lesson in the way London-based Inmarsat’s engineers traced the route of the stricken flight MH370 by analysing just seven empty data packets the plane sent to a satellite.
“The Inmarsat work has shown that, when the need is there, investigators can make a great deal of very little.”
Syndicated content: Paul Marks, New Scientist