SAM countermeasures for passenger jets

Factual Questions
21

http://www.radartutorial.eu/07.waves/Waves%20and%20Frequency%20Ranges.en.html Some frequencies are better suited to pierce through bad weather, but they have less ability to pick up small details and need big antennas. Other frequencies can pick up very small details and have small antennas, but aren’t good at long ranges.

Any aircraft will have multiple sensors on them, each with a wide field of view, meaning there’s considerable overlap. Plus, missiles have heat signatures that can be characterized, so if a sensor detects a small hotspot with such-and-so characteristics that’s small, it’s probably far away; if it is large, it’s probably close.

22

You know how, when you hear someone’s music through a wall, you hear the bass much more than the treble? That’s because low frequency penetrates better than high frequency.

And you know how, when you speed up the recording of someone’s voice, thus compressing the speech in a shorter amount of time, they get a chipmunk voice? High frequency contains more information.
Lower frequency radar has more range but less precision, ceteris paribus. Lower frequency also requires a larger emitter and/or receiver (I’m not sure if it’s one or both).

So, early warning radars may use low frequency and have a range of 200 km, especially if it bounces off the atmosphere. But it’ll only give you a general idea of the target’s distance, speed, altitude, shape. That’s good enough for early warning but not tracking.

And what’s good enough for tracking isn’t good enough for the missile. A missile, especially one that’s designed to shoot down a fighter, has to have a lot of precision because it has to get close to a fast, agile, non-cooperating target. It likely couldn’t afford to use low frequency anyway because the girth constraints inherent to an anti-air missile prohibit the use of a larger emitter/ receiver. It usually doesn’t need it anyway because it’ll tend to use a guidance system that isn’t its own radar to get close to the target and then switch to its radar when it’s close.

Since radio communications obeys the same principles when it comes to frequencies, here’s something that may be informative: Extremely low frequency - Wikipedia

Upside to low frequency:
“ELF waves can penetrate seawater, which makes them useful in communication with submarines. The US and Russia are the only nations known to have constructed ELF communication facilities, with India being in the process of constructing one. ELF waves can also penetrate significant distances into earth or rock,”

Downside:
“One of the difficulties posed when broadcasting in the ELF frequency range is antenna size, because the length of the antenna must be at least a substantial fraction of the length of the waves.”

23

It’s cheaper and safer to just not go there.

24

Rather than modify the planes, I wonder how much it would cost to hire an escort?

25

There’s a conspiracy theory which says that TWA 800 was accidentally shot down by the US Navy, which was conducting missle tests too close to the US coast. I seem to remember the government going to great lengths to deny reports that people saw a missle travelling up towards the jet.

26

I think it’s like $200 an hour, but that’s only legal in some places.

Thank you, I’m here all week!

But seriously, a fighter escort just isn’t a realistic option here. Most fighters cost somewhere between $10,000 and $50,000 an hour to operate, even setting aside the issue of whether they could do anything useful is a missile is shot at a different aircraft.

27

Perhaps surprising, no. Missile Warning Systems (which detect the missile, not radar emissions related to it) have existed for years but are harder to adapt to high speed a/c. so while some fast jets are now equipped with them, most aren’t. For IRCM, they’ll simply dispense decoy flares when they are within the envelope of shoulder launched IR SAM’s, which they generally avoid. MWS are pretty widely fitted to attack helicopters which can hardly avoid ‘MANPADS’ envelopes and perform their missions, and often to transport helo’s and fixed wing transports. But even for the latter types it’s a matter of cost/benefit, even for military a/c. Eventually though such systems will become universal, it’s likely.

The systems proposed for airliners would use MWS in conjunction with laser based IRCM. The sensors and ball mounted IR laser actually track the missile, the laser play on the seeker aperture, and feeds the seeker confusing IR signals to make it break lock. Smarter IR missiles are able to ignore classic IR decoy flares dispensed in a line behind the a/c. More advanced flare systems launch a lot of flares at once (you sometime see dramatic publicity photo’s of that for various helo or transport planes, those large launches would be triggered by MWS) and the flares are more sophisticated. But laser is now the preferred way to deal with smarter IR missiles. The Israeli C-Music system proposed for airliners would work this way, and laser IRCM systems have been successfully used v real missile launches on US helo’s in Afghanistan.

So, practical, reliable hands-off IRCM system for airliners is technically feasible. It’s a question of cost (buying, maintaining, knock on effect of weight and drag, etc). Also a given system wouldn’t be guaranteed to defeat all missiles, IR seeker/processor designers can always improve the counter-IRCM capability of the missile. But against non-state actors not likely to have the latest missiles, it would work against most. It might or might not be cost effective.

However, airliner ECM defense against radar guided missiles is not feasible. The types of missile and guidance systems vary too widely for a single relatively simple automated system to counter even a significant % of the different types. Just dispensing some chaff is not going to defeat all missiles and their radar systems. The Germans had at least somewhat effective ECCM (for their radars) v chaff even by 1944, within a year of its first widespread use in 1943. Even to the extent chaff is still somewhat useful, it has to be tailored to the frequency the enemy is using, again too many different types in the world of radar SAM’s. Also missile warning is harder at high altitude. The MWS used against ground launched IR missiles, IR and/or UV sensors (a combination cuts down false alarm rate) can take advantage of seeing the missile’s launch plume. For an a/c at high altitude the missile might first be seen popping through cloud and after its booster burns out.

Anyway all around, and of course including how much easier it is to avoid areas of hostile radar guided heavy SAM’s (the big threat with IR MANPADS is somebody smuggling them into a non-conflict area), radar ECM on airliners makes no sense at all.

28

If it were a fighter equipped with certain types of modern AESA radar, then the fighter might be able to “zap” a launched SAM with concentrated energy to make the missile go blind and miss the targeted airliner.

But from a cost, fuel, range and practicality standpoint, it’s just not practical. SAM downings of airliners are so rare that you can’t have all several million (or however many) international flights a year crossing dangerous airspace to be escorted. The resources involved would be immense.

29

I’m interested in what how many shootdowns constitutes a “totally freak” occurrence. 18 since 1970 works out to one about every 2 and a half years years. While I’m confident that’s a very tiny fraction of the total flights in the same period, I have to wonder how significant a fraction it is of all crashes during the same period.

30

Besides the cost and the weight, I’d have to wonder how effective Counter Measures would be?

What proportion of SAM attacks would they stop? On something as big and cumbersome as a Jumbo / A380, would the plane still get hit what proportion of the time?

Besides which - if I were really targeting a plane, it personally look at the take off / landing period rather than normal flight - how good would countermeasures be during this period?

31

Airlines’ margins are rather small. Flying around areas of conflict would add cost in fuel as well as in how many flights they could schedule per day on those routes further eating into those meager profits.

Adding the weight and cost of countermeasures would reduce profits even more. And what do they have to lose? They are not at fault nor liable to lawsuits if a plane gets shot down.

There are no incentives to airlines to add these safety measures (and how much safety they add is debatable) to planes other than good PR.

Until they are taken to court and made to pay for flying over areas of known conflict will they even consider changing anything.

I wonder how much it would cost airlines to just add the detection equipment and wire it into the black boxes. That would add to evidence. I just heard today that the black boxes on the plane in Ukraine just reports that the fuselage decompressed explosively. Russia can shrug and point to terrorist bombs on the plane, or shoddy maintenance to the plane itself. But if the investigators could point to evidence that the radar sensors detected high frequency radar signals consistent with SAMs just prior to the explosive decompression, then it would be really lend irrefutable support for a missile strike.

32

Do you have a cite for this? If an airline sends a plane over a known shooting war, why would they not have any liability for it?

33

This is pretty remarkable. So your concern is not to save lives, but just to save the airlines money by better determining liability after everyone’s already dead?

34

Someone with more time could tally all of the crashes listed at the above link and compare the total to the 18 shootdowns you’ve mentioned.

Cost for the various types of older active IRCM systems like the AN/ALQ 144, 147, and 157, are difficult for me to find, but nearest I’ve seen is about 2 milion USD per system, 95 kg of weight, and who knows what kind of drag penalty and other costs for incorporating the system into the airplane. Moreover MANPADS seeker tech hasn’t remained static, requiring more advanced countermeasures than these to defeat them: lasers which pulse specific combinations of radiation, in order to dazzle that specific type of missile seeker. All of which costs more. El Al might be able to get away with it—they have a hobby, not an airline—but good luck with getting other airlines to play along.

Radar ECM? Forget it. The state of the art is closely held by each country’s military and putting it on tens of thousands of airliners would be a good way of losing those secrets. Then there’s the hassle of mounting the electronics for a jamming pod in the airliner, ensuring that the jammers don’t damage the airliner’s own electronic components, and finally , making sure it doesn’t knock somebody else’s airliner out of the sky.

For liability, don’t most carriage contracts have “act of war” exclusions? Of course, the carrier could still be negligent in routing the liner over a known war zone.

35

That’s a good question. But most contracts that I’ve signed (and actually paid attention to) tend to exclude liability for acts of God and acts of war. I haven’t read the contract on a airline ticket, but why wouldn’t those same conditions generally apply?

Let’s inject a dose of reality here. A modernized SA-11 missile system is designed to attack a small, maneuvering jet fighter loaded with countermeasures with a probability of kill that is much, much greater than 50%.

Simply stating that a commercial airliner, which can’t pull 9 Gs, and would not have state-of-the-art countermeasures, is not going to survive an encounter with a surface-to-air missile is not dismissing the value of human lives, or looking out for the bottom line of corporations. It’s a reasonable question on how much should airlines spend to provide only to provide negligible protection.

I’ll also point out that when TSA spends tons of money to buy body scanners that don’t actually detect contraband, those efforts are derided as “security theater.” One can legitimately suggest that placing missile countermeasures on airliners as being another version of that theater.

36

On Wikipedia, I saw only one time where an airline paid compensation to the victims, Korean Air Lines Flight 007. “Passenger pain and suffering was an important factor in determining the level of compensation that was paid by Korean Air Lines.”

I skimmed all the rest of the commercial flights, so I may have missed something. But still, I think the airlines gamble on that not happening.

[QUOTE=Boyo Jim]
This is pretty remarkable. So your concern is not to save lives, but just to save the airlines money by better determining liability after everyone’s already dead?
[/QUOTE]

My concern would be to save lives, but I don’t own an airline. I’m just playing devil’s advocate and trying to show the real-life obstacles of getting something like this implemented.

I was mainly wondering that if we can’t win over the airlines purely on safety concerns, could we at least convince them on finger pointing concerns.

It’s all pointless anyway unless the airlines see a real financial consequence of not valuing human life because human life has no value to airlines once they paid for their ticket. At least, that is what I have seen.

37

The difference may lie in the fact that the KAL007 pilots were the ones who screwed up and flew into unauthorized airspace. The Soviet response (i.e. shooting it down) was reprehensible, but the bottom line is that the circumstances surrounding the KAL007 shootdown were quite different from those of MH17.