Avionics: GPS loss preceded fatal drone crash

Hopes that a new breed of commercial drones can be easily integrated into civilian airspace have been dashed after it was revealed that the loss of the technology likely to make it all possible – automatic GPS navigation between waypoints – led to a fatal accident last week.

The news comes after the maker of a surveillance drone that crashed into its control truck in Incheon, South Korea on 10 May, killing one of the company’s engineers and injuring the two remote pilots, has confirmed that loss of the aircraft’s GPS signal was an initiating event in the accident. But in preliminary findings ahead of an official report from the Aviation and Railway Accident Investigation Board in Seoul, drone maker Schiebel of Vienna, Austria says that the GPS outage should not have led to loss of control of the aircraft, alleging that the remote pilots had reacted erroneously when GPS was lost.

Although North Korea was intermittently jamming GPS in the border region between 28 April and 15 May  it is not known if the jammer was operating at the time of the fatal crash. The South has reacted angrily to the jamming, which has interrupted navigation on more than 600 civilian flights – and it has been likened to a form of terrorism by regional media.

In a statement supplied to New Scientist, Schiebel says it’s Camcopter S-100 drone, a 150-kilogram rotorcraft capable of 220 km/h flight, should have coped in any case because GPS can be lost for many reasons, such as an inability to access the positioning satellites due to obstruction by high buildings. The Camcopter has multiple inertial measurement units that “allow safe operation and recovery in the absence of GPS signals” the firm says.

“All information recovered to date indicates that after a loss of GPS signals to the aircraft’s receivers incorrect handling and omissions over a time period of a number of minutes, resulted in an unfortunate chain of events that ultimately led to the crash,” the statement says. Emergency procedures “to ensure a safe recovery in such a situation” do not appear to have been “correctly and adequately followed” it alleges.

The Schiebel aviation engineer who died – a 50-year-old Slovakian with much experience of the technology – was assisting two remote pilots working for one of Schiebel’s South Korean partners. He was not in control of the aircraft, the firm says. It’s thought the Camcopter was being tested for new duties in border operations.

The accident aircraft had been used by the South Korean authorities since 2008 to police major events – such as the 2010 G20 summit in Seoul, says a Schiebel spokesperson.

The accident will hardly fill people with confidence that upcoming civilian drones won’t present a threat when laws allowing them to ply the skies in the US and Europe change in the next few months. Most modern drones use GPS waypoint navigation – flying from point to point on a map with little expert guidance – and its not clear how many, if any, will have inertial backup, or if users will know how to use it properly if they do. The comment thread here highlights some of the issues.

The ongoing Korean investigation is said to be focusing on the cause of the GPS denial and e-forensics on the charred remains of the control electronics, little of which survived.

Paul Marks, New Scientist

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