Last week's downing of Malaysian Airlines Flight 17 over the disputed territory of Eastern Ukraine has set off worldwide outcries against the conflict, and calls to better defend commercial airlines from missile attack. But is it even possible to defend civilian jets against military-grade weapons?
To understand why it's so difficult to defend civilian planes, we need to look just how broad the range of threats they face is, and why existing countermeasures — of which there are a surprising number — are ultimately ineffective.
How Homing Missiles Work
When civilian planes are shot down — which has happened several times in the last few decades — the weapon in question has almost always been a homing missile. Unlike their unguided rocket counterparts, missiles are, be definition, steerable towards a target. This can either be accomplished by a dedicated remote operator, but more commonly is done with homing technology wherein it's the target itself that leads the missile.
There are several methods for doing so:
Active Homing: Active homing is an all-in-one guidance technology, packing an on-board radar array and the necessary electronics and computing power the array might need. This allows for "fire and forget" missiles that don't need to be monitored throughout their flight, like the air-to-air AMRAAM, but does come at the cost of requiring a much larger, heavier, and more expensive missile. Plus, the size and resolution of the on-board radar is far smaller than the ground-based array that initially picks up incoming targets. This severely limits the size of targets that an active homing missile can follow, essentially limiting them to anti-ship, anti-aircraft operations. These can hit a B-52 but would struggle to pinpoint, say, a UAV.
Semi-Active Homing: Semi-active homing removes the on-board radar array and instead relies on a larger, ground based radar installation — often the same system that initially identified and began tracking the bogies. This results in a smaller, lighter, missile that is far more affordable to produce while actually improving the missile's radar resolution. Unfortunately, the radar beams that the ground station uses to guide the missile in can also be detected by the target and countered. Still, the system (technically known as Semi-active radar homing or SARH) is the most common means of anti-aircraft guidance in use today.
An alternate form of semi-active homing — SALH (Semi-active laster homing) — trades in the radar array for a laser designator. More commonly found in air-to-surface missile platforms, SALH systems can be led by the launching aircraft, a secondary aircraft, or even troops on the ground using a laser designator to "paint" the target.
What happens when military aircraft — even with the ability to counter and evade heat seekers — get hit by a MANPAD. Image via World Affairs board
Passive Homing: When the average person thinks of homing missile, a "heat seeker" if you will, they're thinking of passive homing technology. These systems don't rely on external radar signals but rather detect the emissions of the target itself — light, heat, and sound can all be used to lock onto a target and guide the missile home. Infrared homing, for example, locks onto the heat generated by a plane's exhaust while contrast seekers — those which searches out and zeros in on the spot in the missile's field of view with the most rapidly changing contrast levels — have proven very effective against ground structures and other targets that can only be identified visually.
So What Shot Down Flight 17?
It's been widely reported that Pro-Russian insurgents operating within Ukraine's disputed Eastern provinces employed a Russian-built and -supplied Buk missile system (DoD designation: the SA-11) armed with supersonic surface-to-air missiles armed with powerful proximity-fuse warheads to shoot down the Malaysian Airliner. A Buk (pronounced "book,"not "buck") is a semi-active, mobile, medium-range missile launching system developed in the late 1970s by the Soviet Union as an air defence for front-line troops against cruise missiles, aircraft, and UAVs.
Typically, a Buk battalion includes a command vehicle for differentiating between friendlies and incoming targets picked up by the target acquisition radar (TAR) truck, up to six transporter erector launcher and radar stations (or TELARS) which are the actual missile launchers and are affixed to tank chassis, and another four transporter erector launcher (TEL) trucks, which are just like TELARs but without the integrated firing radar system.
The battalion can be broken down into sets of individual batteries that include one TELAR and a pair of TELs. A single Buk battery can set up in less than five minutes, acquire and lock onto a target in as little as 22 seconds, then dismantle and move again within another five. It's a potent mobile launch system, a "big, heavy vehicle that has big missiles," Randal Cordes, a military intelligence analyst who has worked at the CIA and Pentagon, told Wired. "To use an SA-11 against an airliner, it's brutal overkill."
Each TELAR is tended by a crew of four, and carries four surface-to-air missiles. The monopluse radar affixed to the top of the TELAR is capable of guiding as many as three missiles simultaneously to intercept a target up to 20 miles away flying as high as 72,000 feet. The current versions of the Buk also incorporate passive optical and IR tracking features, though the SARH method is greatly preferred.
The system works as follows: the TAR picks up an incoming target, the command vehicle then determines if the blip is friendly or not through an IFF transponder system before granting permission to fire to the TELARs and TELs. Once the missile is launched, the TAR truck provides guidance until the missile is within range and switches over to its on-board radar for terminal guidance.
One major shortcoming of the SA-11 system is that it really only works properly with the entire logistical support of the battalion behind it. If you've got just a TELAR without a command vehicle, as is suspected in the Ukraine incident, then the crew has no means of differentiating between a Ukrainian Air Force transport plane and a commercial airliner.
"The skill comes in knowing what you want to shoot at," Cordes explained to Wired, as the SA-11 will show the same targeting blip for all aircraft with no mention of the size or type of target. It will display the target's altitude, air speed, and vector, but without a command vehicle — or at least the knowledge of how to pull up IFF transponder codes within the SA-11 operating system, a skill that takes months to learn according to Anthony Cordesman of the Center for Strategic and International Studies — crews are really shooting blind. Combine this lack of oversight with the fact that the missile battery was being operated by a bunch of ragtag hick militiamen rather than properly trained Russian forces, and you've got yourself an international incident waiting to happen.
This is unfortunately not the first, or even fifth, time since the 1970s that a commercial airliner has been downed by surface-to-air missiles. Most recently, a pair of incidents in 2002 and 2003, respectively — one in Kenya wherein an Arkia Israel Airlines (AIA) Boeing 757 was targeted by a MANPAD (man-portable air defence) shoulder-mounted rocket launcher, the other in Iraq wherein a DHL A300 cargo plane was struck on the wing upon takeoff — illustrate the growing dangers of operating commercial airlines in areas of conflict, though granted, the easiest way to defend against being targeted by SAMs is to stay the hell away from conflict regions in the first place.
"Some people say planes should be armed with counter devices. That will go absolutely nowhere," Emirates Airlines president Tim Clark recently told Arabian Business. "If we can't operate aircraft in a free and unencumbered manner without the threat of being taken down, then we shouldn't be operating at all."
Still, in the face of international tragedies such as this, some members of Congress have started advocating for commercial aircraft defenses. US Senator Mark Kirk (R. IL) has already called for the implementation of some sort of missile defence on civilian aircraft.
"They should actively look into mounting active defenses on civil aircraft that are carrying hundreds of people." he said in a press statement last Friday. "It's not too technically difficult to add a radar warning system on an aircraft, where a pilot in command could dispense chaff to defeat a radar-guided missile."
It's so simple, in fact, that a number of defence contractors, as well as the Israeli government itself, have already developed such systems. The Sky Shield, for example is a fibre-laser based Directional InfraRed CounterMeasure (DIRCM) designed to confound incoming passive-homing heatseekers with a disco of laser lights, leading them away from the plane before the missile's proximity fuse activates.
While this would definitely prevent another Kenya incident, this system is not designed to counter radar-based threats like the SA-11. Plus, the million-dollar-a-plane price tag makes retrofitting a national airline like United or Delta an exceptionally expensive proposition.
The NG Guardian Image: Akradecki
The Northrop Grumman Guardian, developed in 2003 after the passage of The Commercial Airline Missile Defence Act, similarly defends against short range heat seeking missiles and has been approved by the FAA for use aboard the Boeing 747, McDonnell Douglas DC-10/MD-10 and McDonnell Douglas MD-11, all commonly employed as cargo and passenger planes. However it, and the nearly identical Fight Guard from Elta Systems that fires civilian flares instead of laser beams, are also both designed to defend against MANPAD attack upon takeoff and landing rather than against supersonic SAMs at cruising altitude.
In fact, according to Bloomberg, the US has spent $US239 million in the last decade alone on designing counter-MANPAD systems, though they remain exceedingly rare on US passenger jets. Overall, the International Air Transport Association (IATA) estimates retrofitting all planes with this technology would require as much as $US43 billion dollars and two decades to complete. And they still wouldn't be able to defend against the kind of attack that took out Flight 17.
The fact is, there's no one size fits all solution, and the piecemeal answers we do have are prohibitively expensive. So, short of outfitting commercial airliners with early-warning radar detection or chaff dispensers, perhaps Tim Clark was right; avoiding conflict zones like the Chinese Bubonic Plague is the safest way of ensuring they get to their destination. [Wiki 1, 2 - How Stuff Works - Wired]
Picture: AP Images