After MH17: The technical fix that could protect civilian airliners from missile attacks

July 18, 2014

Site of a Malaysia Airlines Boeing 777 plane crash is seen at the settlement of Grabovo in the Donetsk region

The awful crash of Malaysian Flight 17 in the eastern Ukraine combat zone seems likely to have been caused by a long-range surface-to-air missile. At this writing, who launched the missile remains undetermined. Regardless of who’s guilty — why is a modern software-driven weapon capable of striking a civilian jet in the first place?

All commercial airliners send out transponder signals that identify them as civilian. In most cases, what’s employed is a protocol called Mode C, which is not used by military aircraft.


Modern radar-guided long-range anti-aircraft missiles — like the one apparently used to shoot down Malaysian Flight 17, like the one the U.S. cruiser Vincennes used in 1988 accidentally to shoot down Iran Air Flight 655, killing 290 civilians — don’t pay any attention to what mode a target’s transponder is in. They lock onto a radar image chosen by the gunner, then once launched relentlessly seek the target.

That’s the old way of designing long-range anti-aircraft missiles. Now that software and improved chips give weapons lots of processing power, there’s no reason anti-aircraft missiles could not be programmed never to lock on to, or try to hit, targets broadcasting a civilian identification code. An international agreement could require this of all nations that make or field long-range SAMs.

Of course verification would be a challenge. But verification of nuclear arms reduction agreements has gone reasonably well, as has verification of multilateral agreements on chemical arms and land mines. There aren’t many nations that manufacture or field long-range advanced SAMs. To get all to agree on programming anti-aircraft missiles so they refuse to strike civilian aircraft is a do-able objective.

Armed pro-Russian separatist stands on part of the wreckage of the Malaysia Airlines Boeing 777 plane after it crashed near the settlement of Grabovo in the Donetsk regionCheating would be a worry. But the world’s militaries have been reasonably good at not shooting at vehicles and ships marked with the red cross or red crescent. And cases of putting those symbols on fighting vehicles or ships have been rare. It would be impossible to guarantee that a military — or a quasi-military such as the Russian separatists in Ukraine — would not try to cheat by broadcasting a civilian code from a military aircraft. But this would only work once.

The weapons officer of the Vincennes saw a radar blip headed straight toward his ship, and made a horrible mistake. Whoever launched the missile that likely destroyed Malaysia Flight 17 would have seen a radar blip headed straight toward him. Today’s long-range anti-aircraft missiles are not programmed to know what they are flying toward, only to seek the blip chosen by the gunner.

This needs to change. Improved electronics could make it practical to program long-range anti-aircraft missiles to refuse to attack aircraft broadcasting on a civilian transponder mode. As ever-more civilian aircraft take to the world’s skies, the need to protect them increases daily.

Manufacturers boast of making “smart weapons.” Someday there might be precision-guided munitions that refuse to lock on to hospitals or refugee centers — GPS locations of such places could be loaded into the bombs’ software. A smart tank that refuses to fire toward a school can be imagined technologically.

For today, the first step should be an international agreement to engineer anti-aircraft missiles so they will not track or seek targets broadcasting in civilian mode. Much of the aviation world is moving to a new. data-rich broadcasting standard called ADS-B. Long-range weapons need to be “taught” that standard too.

In the era of beyond-visual-range missiles, numerous civilian jetliners have been shot down by mistake. The United States and Russian Federation should join to forge an international initiative to prevent this from happening again.

PHOTO (TOP): The site of a Malaysia Airlines Boeing 777 plane crash is seen at the settlement of Grabovo in the Donetsk region, July 17, 2014.REUTERS/Maxim Zmeyev

PHOTO (INSERT): An armed pro-Russian separatist stands on part of the wreckage of the Malaysia Airlines Boeing 777 plane after it crashed near the settlement of Grabovo in the Donetsk region, July 17, 2014. REUTERS/Maxim Zmeyev



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this of course presumes the missile builders desire to not shoot down civilian aircraft.

folks writing the design specifications for weapons to kill everything in sight generally don’t think civilians are all too important.

Posted by Breadie | Report as abusive

While this isn’t a bad idea to try and prevent further tragedies such as this, what is to stop a military aircraft from broadcasting a civillian transponder frequency to avoid these “smart” surface to air missile batteries?

Posted by moop21290 | Report as abusive

Whoever shot this plane down probably knew that was not a military aircraft anyway. No Signal will safe anyone from terrorist and cowards.

Posted by etico | Report as abusive

I cannot understand how such as mistake can happen nowadays. I just can’t. I can only seen this as a deliberated action, rather than a wrong performance of any security system. I do hope this tragedy was not left apart.

Posted by hueteyo | Report as abusive

[…] Technical fix could help ensure other civilian airliners aren’t shot down […]

Posted by July 19, 2014 Grumpy Daily Headlines | Grumpy Opinions | Report as abusive

I hope we don’t make the weapons too smart…

Posted by CanyonLiveOak | Report as abusive

Right, we’ll just define a universal “This is not the plane you’re looking for” message. What could possibly go wrong?

Posted by markhahn | Report as abusive

Yes sadly this is just not a practical idea in the real world. Day 1 of any hot war and both sides (or the underdog) would put a transponder on key military aircraft to achieve first strike. And the red cross/crescent analogy is incorrect. It is widely abused in the mideast with ambulances used for movement of militants and weapons. Also clearly marked ambulances have been targeted in many conflicts.

Posted by Para2 | Report as abusive

Further reading on these subjects: v2-c19.pdf
– From Professor Ross Anderson’s tome, “Security Engineering”.
– The Wizard War: WW2 & The Origins Of Radar

If such systems as Mr. Easterbrook recommends were required or even just made more common, we can be sure that someone would use these techniques deceptively (even if fake “civilian aircraft” signals were only broadcast at low power, momentarily, at a critical moment in the missile’s terminal interception trajectory). There’s no way any military is going to make their missiles so vulnerable to subversion, let alone spend large amounts of money doing so.

From the heading of Chapter 19 of Security Engineering: from Sun Tzu:
“All warfare is based on deception … hold out baits to entice the enemy. Feign disorder, and crush him.”

HOWEVER. Mr. Easterbrook seems to have identified an interesting point. While the USA is reported to have changed their target identification technology/procedures in light of “lessons learned” from the Vincennes interception of Iran Air 655; other nations appear not to have learned similar lessons from similar experiences. There may be some place for diplomacy, in ensuring that certain transponder information displays are present in all missile firing control panels, and that certain training is given in their use to all personnel with capability or authorization to fire anti-aircraft missiles. Along with genuine consequences for anyone wrongfully shooting down a civilian airliner; I think this is a more realistic and desirable objective!

Posted by matthewslyman | Report as abusive

[…] the latest news on flying in the future. From Reuters comes a piece on a technical fix that “could help ensure other civilian airliners aren’t shot down.” And WaPo reports that Senator Mark Kirk (R.-IL) […]

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