Sunday, April 6, 2014

Stealth and Mission Accomplishment

ComNavOps just finished reading a fairly detailed article on another blog that  debated the merits of the F-35 and the Advanced Super Hornet being proposed by Boeing.  One of the points that was made was that the F-35 was stealthier by some factor and, therefore, superior.  That got me to thinking …  Why is a given level of stealth better than another level?  Proponents of various platforms (and I’m talking about aircraft, now) argue vehemently about the levels of stealth that their favorite aircraft possesses, or does not.

Let’s take a momentary side trip to dip our toe into the water of stealth.  Stealth is commonly expressed as Radar Cross Section (RCS) and in units of square meters, the smaller the better.  That’s intuitively obvious and understandable.  The smaller the RCS, the harder it is to detect the stealth object.  The problem is that the numbers are meaningless.  An aircraft has an RCS of 1.0 sq.m., for example.  OK, so what?  What does that mean in terms of detection?  How far away can that aircraft be detected and under what conditions?  I think it’s safe to say that none of us have the training to translate the RCS into actual detection criteria.  Add to that the fact that RCS depends on what facet (angle) of the aircraft the detecting radar is looking at, what frequency the radar is using, backscatter, backscatter detection capability by the detecting radar, ambient interference, and a host of other factors and it’s clear that meaningful stealth discussions are well beyond most of us.  What we fall back on are arbitrary numbers.  Aircraft A has an RCS of 1.0 sq.m. and aircraft B has an RCS of 1.5 sq.m. so we conclude that aircraft A is 33% better than aircraft B.  That’s numerically correct but operationally meaningless to us.

Sure, there are arbitrary levels of “visibility” assigned to various RCS:  Low Observable, Very Low Observable, etc. but how do they relate to real world operations?

What we should be looking at is stealth as it relates to mission accomplishment.  Is the level of stealth possessed by a given aircraft sufficient to allow it to accomplish its mission?  If a given level of stealth is sufficient then having a greater degree of stealth is pointless and simply adds cost.

Here’s a simple example.  Instead of aircraft, let’s consider a person who is trying to walk up to within rifle range to shoot me.  If I see him before he does so, he fails.  If his rifle has a range of 100 m and I can see him at 120 m, he fails.  If, on the other hand, I can’t see him until 90 m, because he’s wearing camouflage (stealth), and his rifle range is 100 m, he can accomplish his mission and shoot me.  That’s simple but here’s the key point …  If he has additional camouflage that prevents me from seeing him until 50 m, he doesn’t gain anything.  He still accomplishes the mission and the extra camouflage didn’t help.  If the mission happens to be to close within 50 m then the extra camouflage is needed.  You see?  The required degree of stealth is related to the mission.

The point is that once the necessary degree of stealth has been achieved, extra stealth is pointless.

Let’s take it back to aircraft.  If an RCS of 1.0 sq.m. is sufficient to accomplish the types of missions that the aircraft is intended for, an RCS of 0.5 or 0.01 or 0.0000001 doesn’t gain anything and simply adds to cost. 

Let’s take it back to JSF and Hornet which is what everyone gets all wound up about.  What level of stealth does the JSF need to accomplish its mission set?  I don’t know and neither do any of you.  Does the base Hornet have sufficient stealth to accomplish the mission set?  Again, I don’t know and neither do you.  Does the Super Hornet have enough?  Does the Advanced Super Hornet have enough?  Supporters and detractors of each aircraft sling RCS numbers back and forth without having any idea of what it means in terms of mission accomplishment.

Advanced Super Hornet - Stealthy Enough?

Again, someone is going to comment that extra stealth will allow the given aircraft to get even closer to the target or maybe fly in formation with enemy aircraft and laugh because they can’t see us even though we’re wingtip to wingtip.  Well, if that’s the mission then the extra stealth is necessary.  If that’s not the mission then the extra stealth is waste.  Remember, stealth is like the extra knot of speed in a surface ship:  each knot above around 20 kts comes at an exponentially increasing cost (I’m looking at you, LCS).  Likewise, each “ounce” of additional stealth comes at an enormous cost.  Therefore, stealth needs to be assessed relative to mission accomplishment.

There is no public data relating stealth to mission accomplishment that I’m aware of.  The JSF is supposed to be stealthier than the Super Hornet but does the difference matter in terms of mission accomplishment?  My gut feeling is that the Super Hornet is sufficiently stealthy to accomplish all but the most demanding missions.  Is that difference sufficient to justify the mind-boggling cost of the JSF program?  I don’t know.  I think the Navy could accomplish its strike fighter missions with the Super Hornet (and maybe adopt the Advanced Super Hornet).  Remember, stealth can be achieved through electronic countermeasures, optimized tactics, deception, and other means.  It doesn’t all have to come from the aircraft’s airframe.  Indeed, the Navy’s rather tepid endorsements of the JSF suggest that they feel the same.  Given the cost of the JSF, I’d like to see the Navy drop the F-35C and continue with Super Hornets and Advanced Super Hornets long enough to go back to the drawing board and design a new, dedicated, optimized Navy strike fighter that isn’t a compromised disaster and doesn’t depend on non-existent, PowerPoint wishful thinking technology – a plane that has a laser focus on the required mission set and nothing more.  Whether that requires stealth, networking, 360 degree sensor fusing, Mach+ speed, etc. should be determined strictly by the mission requirements not by the fact that someone thinks it would make for a nifty PowerPoint slide.


  1. To take your analogy further, while you are walking around in camouflage you also have

    1. A flashlight (radar) which greatly helps your own search and fire control but once turned on shows your location.

    2. Signal flags (radio) which greatly helps your tactical ability to coordinate your forces but once again if waved around discloses your location.

    So you have a hard choice, do you walk around half blind and def but hidden or do you disclose your location with your own technology which greatly helps your ability to find the enemy and talk to your friends

    1. There is answers to those two questions that have been addressed by the B-2. So you do have those things but the enemy cannot detect them like you claim.

    2. What enemies have we flown the B-2 against? Enemies which would have trouble detecting a B-52.

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    1. B.Smitty, you're hovering around the edges of getting the point of the post. Is it the mission of the Navy's F-35C to go flying ten feet from the most modern and capable air defense system our enemies have? If so, the F-35C is incapable (plus, we have F-22s and B-2s to do that - we fight joint). If not, what is the mission set of the F-35C and what level of stealth is needed? If the F-35C's main mission set is standoff missile launches of cruise missiles or long range A2A missiles then all it needs is enough stealth to get within standoff range, launch, and retreat - a much lower level of stealth for which the F-35C is probably overdesigned and over costly. I don't pretend to know the details of what mission set the Navy intends for the F-35C. None of us do and it's quite likely the Navy hasn't taken the time to think it through, either (witness the LCS - designed without a concept of operations) - or maybe they have and maybe that explains their tepid endorsement of the F-35.

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    3. B.Smitty, I'm not considering all-aspect versus partial at all. I'm only looking at the overall level of stealth required for the intended mission set. If the plane is only required to make a frontal approach to within a hundred plus mile standoff distance, launch, and retreat, then frontal stealth is all that's needed. If the plane is required to perform deep penetration and play tag with advanced air defense systems then all-aspect stealth is mandatory.

      See my other comments about what I believe the Navy's F-35C mission set is and how much stealth is needed.

  3. Nice thought provoking article. Althought …
    If you can predict the missions you require over the next 25 years. I very much doubt you can predict the threats or sensor technology. Stealth and AESA \ SAR is out of the box now. I think all that we know from the Raptor and the B2 ( even going back to nape of the earth flying back in the 80’s ) is the stealth increases the likely hood of mission success.
    In most engagements from Subs to Tanks to small arms, who sees who first is generally the deciding factor.
    If it’s worth the cost? That’s a very subjective thing. It depends on the relative value, and cost to a country.
    And also heavily depends on the military future. If there is no war in the next 50 years, has it all been a waste of money or a roaring success?

    1. Beno, you've just raised the "what if" argument. What if we design an aircraft to have "X" set of capabilities and then find out 20 years from now that we also need "Y". OK, we'll design for "X+Y". But even doing that, what if we find out in 21 years that we need "Z". OK, we'll design for "X+Y+Z". And so on. There's a never ending set of "what if" requirements. The problem with designing to "what if" is that the cost and time-to-field becomes mammoth. That's kind of the problem with the JSF. It was designed to a set of arbitrary, "what if" capabilities that were divorced from mission requirements and we've seen what happened to the cost and time-to-field.

      If we design to "what if" then every ship and plane becomes an unaffordable, unachievable item because there's always another "what if" that might render our design sub-optimal. The only feasible design approach is to define a set of reasonably anticipated mission requirements and design to that. If we do that with a laser focus and don't go adding extras, hopefully we can build a plane that is affordable enough that we build another plane in 20 years when mission requirements change.

    2. Thanks for the response.
      Mmmm yes the dreaded “what if”, I think yes I am suggesting that, and no I’m not.
      We do know things will be different in the future, the arms race will continue, we and “they” will continue to analyse capabilities and try to counter them.
      We can’t play the X+Y+Z sinario too much ahead of time, that way lies madness.
      However we MUST attempt to get \ stay ahead of the curve, in a sense DEFINING the “what if” for everyone else, otherwise we start to have to play catch up, with a surety that we have to try to guess what the Russians or Chinese are going to come up with next and try to counter the unknown.
      Like I say Madness.
      To an extent we can pick anything that is defiantly tactically significant and technically capable and push it. Forcing other to follow it, counter it. Then it just becomes a battle of budgets and development speed.
      Stealth ( and all the other F35 capabilities ) is significant. The F35 WILL BE cheaper than the F22 and hence available in greater strategically significant numbers.

      The F18 airframe is not capable of upgrade in this area ( and the other capabilities ) into the next 2 decades. I think it’s pretty much as simple as that?


    3. Beno, I'm with you right up until your last sentence. It goes right back to the point of the post - what is the mission and what stealth do you need to accompish it? If the Navy's F-35 mission is penetration of the most sophisticated air defense system imaginable for the next 30 years then you're correct that the F-18 is incapable of sufficient upgrade. But if that's the mission then the F-35 isn't capable either since it's only a moderately stealthy airframe. The Navy would need navalized B-2s and F-22s. Instead, I think the Navy's F-35 mission is more along the lines of standoff launches of cruise and A2A missiles. If that's the case, the F-18 is quite capable of the needed upgrades and, in fact, the Advanced Super Hornet (check it out you haven't already - stealth mods, conformal fuel tanks, stealth weapon pods, etc.) probably has the needed performance and stealth.

    4. Great article, one of the best I have read on F35!

      This "what-if" kind of goes with some of the problems I have with the F35 and LO. LMT says they can "guarantee" the LO for F35 for the life of the bird, nicks, scratches can be "easily" fixed but, I know you can't answer this because it's classified, how can the RAM/coating/paint still be considered good to go in 25 years? When you consider the pace of electronic advancement, kind of hard to believe that the LO of the F35 will still be good in 10, 20 , 30 years? Let alone how much it will degrade due to exposure and dents.....

  4. You are think point defense but its more than that. You have to consider a map with circles drawn around every radar unit. The bigger the circles the less units needed to defend X territory. Also the bigger the circle the more likely the enemy can overlap and encircle primary targets while forcing our forces through troughs, unless we come in mass and fight our way through the defensive ring. The smaller the rings the more you can thread the needle to the target without being seen and make the enemy cost to fully defend his territory extreme. 300+ air defense systems are expensive.

    By your example the trooper is not the target he is there to stop me, the targets are the command, marshaling yards, supplies, supply lines, civ infrastructure, communications etc.... all deep in your territory. Now the most desired and least expensive option would be a picket line with overlapping observation to stop me from penetrating in the first place. However the smaller I shrink those circles the more this becomes impossible so you have to withdraw back to a point defense but this is extremely costly because the number of targets and worse if I can freely orbit in between I can still strangle you and box you into a distributed fort defense while I concentrate on taking one fort at a time at my prerogative using your point defense strategy.

    Stealth is the US version of insurgency war. You may take territory but we can sneak between your lines appear at will and attack critical points before again disappearing. Stealth means I can hit from all over while using other assets (cruise missiles) to grind down your concentration point defenses so I can hit them also.

    1. Even point defense if you can put one defender ontop of the target to protect it but if you can cut his range to were he cannot see you before you can launch you cause the defender to now place 3 or more pending range to defend one point. He must place his defenders forward enough to detect you before you range the target, and then go around the target 360 degrees with overlapping rings in between. The cost curve to the enemy grows very fast with stealth. And of course don't forget the smaller the circles the less radars we must hit with cruise missiles to open a gap.

      Stealth is expensive but it is just as expensive for our enemies defense.

    2. C-Low, you are describing a generalized vision of stealth which misses the point of the post. Is flying between high tech air defense points a mission of the Navy's F-35C? If it is, then it needs whatever level (but no more) of stealth that requires. If it is not, it doesn't need that level of stealth - that's the point of the post.

      Designing for ultimate stealth levels will result in every plane being an unaffordable nightmare. How many B-2 bombers do we have? We have only 20 because the cost for that level of stealth was unaffordable.

      How many F-22s do we have? Again, they proved unaffordable.

      The JSF, with only moderate stealth, is unaffordable (to be fair, much of the unaffordability is not stealth related) and is decimating other acquisition programs. At least from the Navy's perspective the F-35C is overdesigned for its mission set and, hence, unaffordable.

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    4. B.Smitty, I've got to respectfully disagree. Cost was the overriding issue. Yes, there were many peripheral factors but it was cost. If the B-2 had cost only $10K (to be ridiculous to make a point) we'd have built hundreds. For its time, it broke the bank and we only bought 21(?). The F-22 was scaled back and back, in terms of procurement numbers as the cost skyrocketed (again, for its time). The F-35 was conceived as the "low cost" alternative to the F-22. It was all about cost.

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    7. B.Smitty: "We had the money but chose not to go that route."

      Isn't that kind of the definition of unaffordable?

      I guess, technically speaking, if we were willing to devote the entire DoD budget to just B-2s or F-22s then, sure, we could afford more of them but that was deemed unacceptable within the overall DoD concept. In any practical budget assessment, they were unaffordable.

      It's the same case as the carriers. We're currently devoting an entire year's shipbuilding budget to a single carrier every five years. That's simply unaffordable since it's driving the fleet to ever smaller numbers. Yes, technically speaking, we can continue to do that but the result would be (is even now) unacceptable. We can't afford to do that within the concept of what we want to accomplish.

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  5. One thing about Stealth as a technology that concerns me is that to some extent it seems like the old armor/gunfire battle. Yes, you can armor a tank to a fare thee well, but its generally easier and cheaper to build big guns.

    Alot of the stealth technology seems to rely on A) Shape B) exotic materiels and C) exotic coverings. None of which are easy to take care of. Especially in the types of environments the Marines/Navy will be operating out of (Mud. Salt. Wind. Sun....)

    On the other side you have radars and processing capability, which seems to me to be advancing at a much faster rate than materiels science. So the F-35 which was intended to last 30 odd years may have its stealth tech obsoleted in 7. In which case we have a plane with bad flying characteristics and compromised stealth. And we haven't been able to afford a more conventional plane that can fill out our ranks with much better flying dynamics.

    Stealth is just being sneaky on your way to execute your mission. To a certain extent it doesn't matter whether its exotic technology or low level flying or
    the Klingon cloaking device. You need just enough to get the job done.

    I can see a role for stealth aircraft, but I guess I see them more like the B2. If we get into a fight with Sinostanrovia which has a long pacific border, The B2 could likely get in close enough to launch stealthy stand off missiles in the early days to take out nasty stuff to clear the way for more conventional planes.

    Or we could have a low volume plane like the F-117 that uses tactics and materiels to sneak in while its less stealthy brethren raise hell at higher altitudes. Its job would be, again, to sneak in and nail high value targets so that the less stealthy aircraft can use more conventional tactics.

    Either way, we aren't betting the whole bloody bank on making our main aircraft for three branches stealthy at the cost of almost all else.

    We used 'Stealth' in WWII in Submarines that could sneak close to the Japanese shipping lines and nail high value targets (shipping and some warships).

    It was very valuable. But we didn't put the Essex production line on hold until we could make a submersible aircraft carrier because 'Holy Cow a stealth CV could sneak up RIGHT ON JAPAN and initiate strikes!' Stealth there didn't match the mission needed.

    I think we are on an expensive, dangerous, and ultimately fruitless road.

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    2. I see your point.

      I guess my greater point is I wonder if Stealth is getting to the point of diminishing returns. The armor analogy only partially applies in that it (seems) to take a heck of alot more technology to protect the tank than it does to make something to kill it.

      In the same way, I think that radar and processing technology are and will continue to race ahead of stealth technology. First off, it appears that the Chinese got alot of knowledge of the F-35 a few years back off of our computers. So they can start designing to defeat it. Secondly, the F-35 stealth technology continues to age before it even its initial production. Finally, I think even if stealth continues to function, its going to reach a point where it doesn't matter.

      I read this:

      "search radars are at VHF [frequencies] and getting lower, and with computer processing power they are getting much better. They can see them [fifth generation attack aircraft] hundreds of miles away, just like any other aircraft."

      So what if they can see an F-35 at 300 miles where they could see the F-18 at 600 miles using advanced technolgy. Sure, the F-35's stealth is still functioning, but not well enough. And the money put into its stealth is sunk. While you can upgrade avionics and radar processing power you can't change the shape or materiels of the F-35 very easily at all.

      Worse, the F-35's performance keeps getting worse. So if a ground or air based radar can see the F-35 out far enough, it can vector a jet in close enough that can kill it. And the F-35 can't as much about that situation as an F-15 can. Heck, at least the F-15 can run.

      I just wonder if all this money sunk into a totally stealth fleet is a suckers bet. IT takes so long to depreciate the jet that its biggest advantage won't be much advantage at all half way into its life.

      Again, Just my uneducated thoughts, based on what I've read. I'm fully willing to admit that I'm not seeing something.

  6. I think you need to look at the designator of the aircraft and address the mission it is supposed to do. An F designator means the primary duty is Fighter with a secondary mission of Attack. You are describing (against a SAM site) an Attack mission.

    A fighter's stealth usefulness has to be measured in the ACM environment. IN this environment turning on you flashlght is the worst thing you can do. RWR gear detects at TWICE the range of your radar detection. even with an AWACS aloft providing a picture then visual size and vector approach becomes the most important point. Since most people we will face will not be able to put an AWACS up what is the value of stealth for $100Ms per airplane?

    A Fighter's Attack stealth usefulness has to be measured in the Suppression environemnt (against SAMs). No fighter is expected to take on a SAM site by itself. The jammer support, wild weasel missions, etc. make stealth no a cost effective value in attach missions.

    Read the GAO report on the Desert Storm effectivesness ( I believe from 1997) of stealth and smart weapons. Also read about the history of ACM and what Tactics Aces used to defeat their opponents.

    Obviously you can tell I feel that stealth is an VASTLY overrated feature and NOT worth it. I would rather have MANY more non stealthy A/C than a few stalthy. History shows that the side with the most of the almost equal weapon wins.

  7. I agree with you almost entirely. I'd much rather have many non stealthy A/C (with great other qualities, like some of the Sukhois out there) than a few stealth A/C. Especially when, like with the F-35, the Stealth is very directional and very prone to degredation through the environment. From what I've read that's an issue the Navy still doesnt' have a handle on with the F-35C.

    As to paying attention to the designator.... why bother at this point? IIRC according to the Air Force the F-35 was supposed to be the more ground attack side of the Raptor/Lightning duo. Kind of like an F-16 built more to an F/A standard, with the weighting more towards attack.

    But with the Raptor production done... the Lightning is supposed to replace:

    F-15 (Air superiority)
    F-16 (light air combat, attack grafted on)
    F/A-18 (multi-role fighter attack, with attack emphasis)
    A-10 (heavy slow ground attack/tank killer)
    AV-8 (lighter ground attack with some air to air capability)

    About the only thing that they say it's not going to be taking over is the cargo role. I kind of wish they would so we could call it the F/A/C -35 Hercules Lightning Thunderbolt II

    Given its 'cheaper' stealth and the costs it has to pay in ACM to achieve that stealth... holy cow...

    Yes. At this point I'd be happier keeping the F-15 and F-18 while they try to come up with something better that doesn't bet the house on stealth...


  8. The real problem with the F35 is that it is replacing the F-16, A-10, AV-8 and F-18, yet the acquisition costs of the airplane ensure that it will never be able to be procured in sufficient quantity to replace these "lower end" aircraft.

    As noted, the requirement for stealth has never really been explored publicly. Why for example is the B-52 firing advanced long range ALCM sufficient for the strategic bomber mission, but an equivalent program for legacy/non stealthy strike aircraft not viable? How much of the interdiction and CAS missions should be filled by artillery, to include short-ranged ballistic missiles like GMLRS and ATACMS?


    1. GAB,

      I don't think the F-35 is "replacing" the FA-18 as much as supplanting the older FA-18s. Which are obsolete and the Navy probably wanted to retire anyways.

      According to Naval Aviation Vision 2014-25, the roadmap is to have mixed airwings of F-35C and Super Hornets in 2025. Same goes for the USMC in terms of their Marine Air Wings.

      And TACAIR Navy never really wanted the Hornet to begin with. It was a sluggish, short-ranged dogfighter which didn't couldn't carry the load of its predecessors. They only got what they really wanted with the Super Hornet - which is almost a completely different aircraft.


    2. Matt,

      When the F-35 hit milestone A in the acquisition process, it was originally slated to replace the F-18: as the issues with cost, schedule and performance grew, the Navy very much looked upon the project as a supplement, rather than a replacement for legacy aircraft. I think this was a wise choice by the Navy.

      The original F/A-18 was very much wanted by the Navy; at the time it was an A-7 replacement.

      The failure of the A-12, and the collapse of the Soviet Union left Navy air in the situation it currently finds itself in.

  9. Speaking of platforms, I'm surprised no one seems to be talking about drones. Looking out 10+ years, doesn't it seem likely that they'll make a lot of current thinking about aerial warfare as obsolete as the carrier made the battleship?




  13. I think USAF mistake was to take LO and spread it to the fleet, USAF should have just replaced F117 with another "silver bullet" type. If you only need LO for first day kick down the down war and some really hard to reach targets, why do you need to spend all the money spreading LO/VLO to the fleet and paying for the upkeep of LO on all those birds?

    I can't wait to see how especially those USMC F35Bs look like in a few years, after cruising around the oceans for a few years plus operating on a "austere" pad, let's see if the services keep that nice pristine factory LO intact and how much it will cost them. The budget numbers and hours will be revealing....

  14. Over at War is Boring they hold the same view as ComNavOps

    I think this quote is a little worrying " F-35 will provide targeting data to the F/A-18E/F from deep behind enemy lines".
    Best make sure the F-35C numbers are sufficient to absorb significant losses.
    I thought it was the role of UCLASS to fulfill this role.

  15. "Remember, stealth can be achieved through electronic countermeasures, optimized tactics, deception, and other means."


    Yes, except not really. Some observations:

    1. Electronic countermeasures may make you difficult to target, but it can also serve as a tactical altertment to the enemy (“Funny, my screen just went blank!”)

    2. I'm not sure what is meant by ‘optimized tactics’. But I’d think it’s very hard to defeat or subvert a modern air defense system with tactics alone.

    3. As to ’deception’, subterfuge might work the first time. Unless your enemy is smart and recognizes his center of gravity (i.e. what you want/need to blow up). The North Vietnamese figured this out very quickly in 1965.

    I think the author views stealth as a binary variable. It either works 100% or it doesn't work at all. But I tend to think that at least for tactical aircraft, stealth is really more of a step function or a curve.

    There’s probably very little benefit to a ‘marginally stealthy’ aircraft. It maybe only buys you a few extra miles before you get detected, while the costs in incorporating stealth features are large relative to the gains. And by costs I mean both financial costs and tradeoffs in other performance characteristics: speed, payload, endurance, etc..

    Then there is also probably some magic stealth threshold where being ‘moderately stealthy’ buys you a whole lot of tactical benefit relative to the marginal costs. I would HOPE the F-35 would fall in this category. It’s got enough stealth to give it a competitive advantage in a dogfight, but not at the expense of being a purely stealth fighter.

    Lastly, I would think at some point there are diminishing returns where any further attempts at stealthiness come at enormous costs relative to the gains. At this point you’re in the F-117 territory – where the only thing the aircraft can really do is be stealthy. We don't need to be there anymore.




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