Aviation experts have cited multiple possible reasons for the problems in the multi-country effort to locate the Malaysia Airlines jetliner that dropped off the grid over the South China Sea four days ago.
First, startling as it may be in an age of sophisticated satellite tracking technologies, some aircraft still depend solely on radar that at times can lose contact with air traffic controllers. Even if the latest GPS technology is on a plane, it may be damaged -- or unused, experts say.
"The challenges of locating a lost aircraft ... can be enormous, and could be made worse by weather, currents, accuracy of last known position, etcetera," said Frank Graham, Jr. president of AeroVox Forensics, an aviation security consulting firm. "Besides, it's a big ocean out there."
Malaysia Airlines Flight MH370 was en route from Kuala Lumpur to Beijing with 239 passengers and crew onboard, when air traffic controllers suddenly lost contact with the aircraft while it flew somewhere over the sea between Malaysia and Vietnam. Efforts to locate the Boeing 777-200ER jetliner have so far been unsuccessful for reasons that remain unclear.
A Boeing 777 aircraft (Photo: Boeing Co.)
On Tuesday morning, the search took a new twist as Malaysian Air Force officials told cable television network CNN that the aircraft may have veered hundreds of miles off course in the opposite direction just before it vanished.
The most recent similar incident came in 2009 when an Air France Airbus flight from Rio de Janeiro to Paris crashed over the mid-Atlantic. Search and rescue teams didn't find debris for several days, while the fuselage wasn't discovered for almost two years.
Finding the exact location of a downed plane can be tricky if it was beyond radar coverage and lacked equipment that could transmit updated positional data back to the airline, Graham said.
"Some planes have that capability and some don't," he said. "There are still instances where controllers and airlines rely solely on position reports via radio from the crew to know where the airplane is."
Loss of radar contact isn't uncommon, especially over long stretches of ocean, Graham said. "While there are a variety of ways an aircraft can transmit positional data, the equipment must be installed in the plane, properly maintained, and actually in use."
Requirements, procedures, and practices, as well as equipment configurations varies from plane to plane, airline to airline, and country to country. "The whole world isn't like the continental US where you can track every flight yourself unless the operator requested and received a block on the [publicly transmitted] ASDI (Aircraft Situation Display to Industry) data," Graham said.
Aviation authorities around the world are starting to implement plans to supplement radar with GPS technologies, but that won't happen everywhere for another 10 years or so, he said. Eventually, all position data will come from the plane. "We're not there yet," Graham said.
The major aircraft tracking technologies include Automatic Dependent Surveillance-Broadcast (ADS-B), said Ric Peri, vice president of government and industry affairs at the Aircraft Electronics Association. Rather than relying on a radar ping, ADS-B uses a GPS signal and an aircraft's navigation system to determine the position of a flight and then broadcast that information, he said.
Many U.S carriers have begun using the technology -- all major commercial aircraft in the U.S are required to use it by 2020, he said. The technology has proved especially useful over areas like the span of Atlantic Ocean between Hudson Bay in Canada and the Irish coast that lack radar coverage, he said.
Other regions of the world, though, still depend entirely on radar signals, he noted.
The missing Malaysian airliner was also a Boeing 777, which was first used nearly 20 years ago. "The electronics and the technology that was in the aircraft was probably certified in the five-year time frame before that," Peri said. Certification of such technology takes time, so it's not unreasonable to conclude that the missing aircraft may have carried 30-year old tech, he added.
The aircraft Flight Data Recorder and Cockpit Voice Recorder should each have had attached beaconing devices designed to activate if the aircraft crashed into the sea. The beaconing system is designed to last for about 30 days underwater. "But those are basically homing beacons, so they are fairly low power," Peri said.
It's also unclear with the lost aircraft carried an Emergency Location Transmitter (ELT) that's designed to transmit an emergency signal in the case of an accident.
"If in fact the aircraft had a crash, a force switch built into the unit would turn it on," Peri said. The device would broadcast a signal that would be picked up by Search and Rescue Satellite Aided Tracking (SARSAT), a worldwide search and rescue monitoring system used to locate everything from missing hikers to missing airlines, he said.
U.S. commercial aircraft are required to have an ELT.
It's quite unusual for an ELT not to work as designed, Graham said.
"It takes a long time and a lot of testing and certification trials to change the way things are done in commercial aviation," Graham said. "Look how long the iPad was out before the FAA [cleared] it for use in the cockpit. And actually, that was pretty fast, comparatively speaking."
Experts noted that some airlines, especially those outside of North America and Western Europe, often lack the latest tracking and emergency technologies.
Jaikumar Vijayan covers data security and privacy issues, financial services security and e-voting for Computerworld. Follow Jaikumar on Twitter at @jaivijayan or subscribe to Jaikumar's RSS feed. His e-mail address is jvijayan@computerworld.com.
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