Greetings, this is dslyecxi. In today's episode of Art of Flight we're going to look at the most demanding form of helicopter support: Danger Close airstrikes. We'll cover what exactly qualifies something as being danger close, what to consider when setting up for your attack run, example scenarios, the danger close attack cycle, some special risk mitigation techniques, and more.
In this guide we're focusing primarily on Danger Close, so in order to streamline it a bit, we'll establish some prerequisites and understandings up front so that we don't have to retread too many basic CAS concepts. It'd be a good idea to have watched my Light Attack Helo and Aerial Weaponry guides at a minimum before getting into this one. Pedestal Attack and Target Fixation are both recommended as well. You can find links to those in the description.
The expectation is that as a pilot you know how to conduct typical close air support, understand how your airframe works, how your weapons function, and are in a mission in which you've paid attention to the briefing, have followed along with the progress of friendly troops via map and radio contact, and have supported them over the course of it.
You have a mental map of where you are, where friendlies are, where and what the enemy might consist of, you know what friendly and enemy troops look like and can distinguish between them, and you're ready to respond to further tasking as needed. With all that being the case, let's get started.
When operating as part of a combined-arms scenario, attack helicopters typically provide three general types of air support in Arma. These aren't the only roles they provide, but they are the ones most relevant to working with infantry units.
The first is battlefield interdiction. This is when a helo is roaming the area of operations trying to prevent enemy, particularly in vehicles, from approaching friendly forces. This involves an orbit where you're engaging vehicles before they ever come into firing range of friendlies.
Next we have close air support. This includes things like ground forces asking for you to soften up an enemy position, bunker, or otherwise doing a strike that's somewhere in the realm of 200 or more meters away from the nearest friendly ground element, as well as striking enemy vehicles that are within engagement range of friendlies.
Finally there's danger close. This is everything within roughly 200 meters of friendlies, where a big part of the strike is making sure that friendly positions are accounted for. Any time you're hitting targets within that range, you're considering it to be a danger close strike and are factoring in all the things we'll be talking about in this guide. The point of a FAC or other ground unit calling something as 'danger close' is primarily to help indicate that friendlies are in the vicinity of the enemy. It's a means of ensuring both sides - air and ground - are aware of the risks involved with airstrikes.
You can think of danger close as encompassing a scale of possibilities, where on the lowest level the pilot is aware of friendlies but decides that they don't factor into the current targeting situation, whereas at the highest level there's a friendly adjacent to the enemy and you have to be creative to not hurt the friendly.
These narrow margins and close proximity of friendlies to enemies can require a great deal of precision and care on the part of the attacking pilot, and small errors in weapons delivery or incomplete situational awareness can easily result in friendly casualties.
Aside from the scale of possibilities mentioned previously, danger close tends to occur in two different contexts.
The first and most common is as an autonomous act by a pilot. This is where you see something within that danger close radius of friendlies, consider the friendly situation, and strike the enemy. Autonomous strikes are common when covering a ground force in which your situational awareness is high and you're never far from them.
The other possibility is that of a called strike. This is where someone on the ground, a squad leader, platoon commander, or FAC typically, asks you to hit something that either they call as danger close, or you recognize as being such.
Danger close strikes tend to occur because of either sudden situations that exploit a weakness of ground forces, or increasingly difficult situations that ground is unable to deal with on their own. As an example of the former, an armored vehicle suddenly rushing up to friendly forces that are unable to defeat it with their organic anti-tank assets may require a danger close strike as a solution. For the latter, any time a friendly force is put in a situation where they're unable to fight off the enemy on their own, the situation may require a danger close strike to buy time or space for friendly forces. This can be a defense threatened with being overrun, a friendly force trying to break contact with the enemy, supporting a hot LZ or extract, or even a friendly force attempting to break out of an encirclement.
While danger close often happens in time-sensitive contexts, it's not inherently hasty, but it is inherently precise.
Let's take a look at the kind of scenarios you can expect to employ danger close in. These are representative but not entirely comprehensive. For this we'll be using a basic infantry platoon of friendlies as illustration - Alpha, Bravo, and Charlie squads, along with a Platoon Headquarters element. We'll also use these infantry icons to indicate individual unit positions for some scenarios.
Sometimes danger close will take the form of friendly forces in a clearly-defined area calling for you to strike something that's also clearly distinct from them. In this example, one squad has been surprised by enemy rushing them from across the road. You can easily distinguish the friendly from enemy positions thanks to the road, you know friendlies are holding in place, and thus it's easy to make runs on the enemy positions.
A variation of this is when friendlies are holding a well-defined position like this castle, and the enemy is approaching from a variety of angles. Since you know friendlies are not going to be outside of the defensive position, you have clarity in that anything moving around outside is enemy and can be engaged - all the way up to the walls if need be.
At other times things will be a little less clear. Urban areas are a good example of this (Chernogorsk or something on Altis), where it might take some effort to figure out exactly where everyone is and where the enemy is relative to that. Ground forces can help out in these scenarios by employing smoke, positioning themselves in a way that's more clear from the air, etc. This example is a bit lacking in clarity - the enemy and friendly positions aren't aligned to any particular urban feature. By contrast, here's the ground commander having repositioned their units to where they hold an area that can easily be described to air - in this case, everyone is within an area defined by roads, and anything outside of the box they create is considered hostile.
Another typical example is protecting an insert or extract. In these situations, you may be striking things very close to the landing zone, with the intent of suppressing or killing enemy that threaten it. Maintaining awareness of the friendly troops as they move to board or dismount from their helos is the important thing here, as well as ensuring friendly helos don't get between you and the targets.
Sometimes you'll be in a situation where the enemy is able to rush friendly positions with a vehicle that at least one element is unable to directly stop. If a squad is out of anti-tank assets, and some kind of armored vehicle rolls into their position, you may be needed to surgically remove that vehicle if no other ground elements are able to quickly or easily assist. Here we can say that Charlie is out of AT, and this BMP is thus able to rush through their position unchallenged. While Alpha and Bravo could potentially hit it, there may not be time to wait for them to get into position, as the BMP might very well wipe out Charlie in the meantime. This kind of situation is the perfect one to use a steep or even pedestal attack.
The cycle that a pilot goes through when conducting danger close work is structured after the OODA loop, by Colonel John Boyd. This is an interpreted/streamlined version of it for our purposes. We'll simply call it the Danger Close Cycle. This consists of four phase - observing, orienting, deciding, and acting - that continuously loop. For this section I'll be using footage of doing CAS within our sessions to illustrate the different loop elements.
The first stage is observing. Observing is what you'll be doing most of the time when flying around as CAS. You're paying attention to your radios and staying up to date with your map to stay aware of where friendlies are, while continually searching for threats that you can engage. Since typical CAS is out of scope of this guide, we'll treat observing as the period between doing other things in the mission like typical air strikes and similar.
The things you're looking for during this phase are both visual and audible. The visual elements are threats that are either within danger close range of friendly forces or likely will soon be, and particularly highly mobile threats like vehicles, or intact enemy elements that seem to be approaching friendlies from a direction they don't have well covered.
From the audio standpoint you're listening to your radios and updating your understanding of the situation based on what's being said. If you hear things getting hectic on the radio for a given element, this can cause you to gravitate their way in order to be closer to help if required.
The next phase is triggered either by you deciding on your own that there's something that needs your immediate attention as a danger close strike - triggering an autonomous strike - or receiving a radio request asking for a danger close strike, which is a called strike.
As soon as you understand that there's a need for danger close, you need to do a self-assessment.
Is your situational awareness high enough to allow you to immediately act? If it isn't, take the time to refine your SA until you're confident you understand where enemies and friendlies are, and how they factor into your upcoming decision. If you have a copilot or gunner, they're of great help in assisting with this.
If you spotted the target yourself, you can move on to the next phase, but if you're being called onto a target you haven't already seen, you need to first locate it as well as nearby friendlies. There are many things a FAC can do to help make this aspect easier, some of which you can ask for in order to develop additional clarity on the situation.
The FAC can use signals such as smoke to indicate a target and draw your eye to it. If smoke is being used, make sure you know what it represents, and make sure that there is only one of that particular color of smoke active in the area. If they call that a target is marked by red smoke, but you see two red smoke plumes in different areas, you need further clarification from them.
You can also ask the FAC to paint a more detailed picture of the situation, giving them the chance to explain the ground situation in further detail.
When a strike is autonomous - which is to say that you're doing it without coordination with ground due either to time pressure or because comms have been lost - you need to be particularly aware of what's happening on the ground. You need to be aware of the things you don't actually know, and also be able to make educated, informed guesses to help fill in any gaps. The more CAS experience you have, the faster you'll be able to work through these concerns.
Once you have an appropriate level of understanding of friendly and enemy dispositions and what's being asked of you, you have to decide how to deal with it.
There are a few different things you need to figure out at this point.
First, what needs to be done to solve the danger close situation? Do you and your aircraft have the capability, including weapon types and ammo type/quantity, to do what's needed? Can you be sufficiently accurate with the required weapon?
Next, how should you approach? You need to be able to find a solution to the situation based on the employment considerations of your weapons. Are there risk mitigating techniques you should use? We'll go into detail on what those are later.
Finally, is there anything ground needs to do to help increase the chances for success/minimize the risks for friendly fire? You can ask for the ground element to do things like go firm, take cover in buildings, or orient alongside a clearly air-distinguishable terrain feature if it would help to make the strike significantly safer.
The only thing left to do in this iteration of the loop is to act upon the decision you made. This isn't always proceeding with a strike - sometimes the situation is such that a strike attempt will likely just make things worse. In that case, let the ground element know that you're holding off and give them an idea of what they can do to facilitate a strike.
If it's a called strike that you think you can achieve, communicate your intent to the ground element and get clearance if necessary.
Once you have clearance, direct or implied, you execute your attack plan.
The point of no return is when you fire your weapons. Before you do this, verify that everything you see is what you were expecting to see, and that the target is valid. If you have ANY DOUBT WHATSOEVER about the validity of the shot or your ability to make it, or the situation seems significantly different than you expected, DO NOT FIRE. You can't bring a rocket back once you let it loose, and taking an unsure shot is a sure way to hit friendlies. If you wave off and don't fire, take some time to assess the situation and communicate with who you need to. Come back around if required and try again.
Once you've made an attack and put rounds on the target, you'll either need to conduct a battle damage assessment yourself - simply looking at what you shot at and seeing if you knocked it out or otherwise accomplished your goal - or rely on a ground element like a FAC to tell you what the effects were.
Bear in mind that while you can reattack a target, you should communicate this with your FAC to deconflict with any friendlies that might have moved nearby since your prior attack.
Once done with the target, you go back to observing.
For this next part, it's important that you've already seen my Aerial Weaponry guide, as we'll be building upon concepts from it as well as using terminology established in it.
Now that we've seen a variety of typical danger close scenarios, let's get into the technical aspects regarding how to actually solve them.
The first thing we want to establish is what exactly the gun-target lane is. I'm calling it lane instead of line because in this usage, we're concerned not only with the direction but also the width of it at a given distance.
This visualization demonstrates the concept. Here we have it set for miniguns. The inner section is a generalized dispersion representation. This is set to twice as much dispersion as FFARs have, so it's 22 mils in width. I decided to set it this way so that it acts as a one-size-fits-all concept. At any distance, this represents the area that our munitions can end up dispersing into. The color-coding here is the slant range as it relates to potential effectiveness, where green is close range, white is mid, and red is long.
The red bordering region represents an additional consideration for margin of error. In the case of miniguns, this is just a bit of additional padding. All together, this is a good indication of just how close you can safely put minigun fire to friendly forces, assuming of course that you're skilled with employing them.
The dot sizes for the dots close to the aiming point are a bit larger to indicate that that's the area most relevant.
When we put this into a mode that is based around FFAR employment, the lane changes significantly. The error margin now represents the approximate potential blast and wounding effects of an FFAR, staying constant in size at 60 meters of width, then becoming 20 mils wider than the inner zone past the range at which 60 meters is less than 20 mils - so right about here. Units within this range can potentially still survive, but they'll take increasingly greater damage the closer they are to the inner lane. Units outside of this range can still be wounded, but it shouldn't be severe if it's only a single rocket. Here we can see how stance and proximity influences the damage any unit in this area would take from an FFAR.
Now that we know what the gun target lane is, let's look at how it comes into play.
A golden rule of close air support is that you should always make attack runs parallel to friendly positions. This is generally true, particularly for fixed-wing aircraft, but there's a lot of nuance that's worth illustrating for helicopters, and it's a rule that can be broken so long as the pilot knows how to do so as safely as possible. There are ways to do perpendicular attacks that mitigate the risks, but first let's go over what exactly those risks are.
The typical example of this concept is what you see here. Friendly forces are occupying a town, with the enemy approaching from several directions. If the FAC calls you in for an attack, you're able to pick a direction that allows you to rake along the enemy forces without fear of hitting friendlies. Since there are no friendlies along or within the gun target lane and the beaten zone never overlaps friendly positions, there's little risk of a round striking friendlies if it goes long or short.
When you rotate your attack direction such that the gun target lane intersects friendlies, making it a perpendicular attack, you see how the beaten zone then becomes a liability. You end up flying in the direction of friendlies, seeking to strike a target between you and the ground element or perhaps past it. There are several things that can go wrong here, such as gunner aiming error, ranging error, and munition dispersion. Even simple confusion as to where exactly the enemy position begins can cause you to shoot at the wrong thing.
In this case, what if you mis-judge the distance or some other factor that causes your rocket to be higher or lower than intended? A small vertical aiming error becomes exaggerated due to the attack profile, making short or long rounds potentially impact friendly positions.
This is the fundamental rationale for doing parallel runs instead of perpendicular ones - you want to avoid having friendlies positioned between the aircraft and its target or beyond the target. In a parallel run, dispersion or aiming errors will cause munitions to fall on the enemy either way, or at the very least, to not fall on friendlies.
Furthermore, in a parallel run, being shot down means you aren't likely to crash on friendlies. If you lose your engine, you're able to turn towards friendly lines and autorotate easier than if you were headed into enemy territory.
Angle of Delivery
The trick to doing a safer perpendicular attack - or any attack in which the gun-target lane intersects friendlies - is based on the angle of delivery relative to friendlies.
When you receive a danger close request that has either a given or implied ingress direction, the typical solution is to orbit into position and then turn in towards the target to make your run. The complication for danger close happens when the time available to set up for a run is compressed due to urgency - the time required to get to the ideal offset might mean the run happens too late to be effective. These techniques can come in handy in situations like those that don't allow you the opportunity to set up for that ideal approach.
At the most basic level, you want to ensure that the angle between you, your target, and friendlies is such that aiming errors, dispersion, ricochets, and similar factors couldn't possibly be severe enough to miss the target and hit friendlies. The easiest way to accomplish this is through the use of plunging fire, which you achieve by doing diving attacks. Firing from closer ranges is also a good way to increase your accuracy. Combined, these help to minimize the size of the danger zone for your munitions and also minimizes the chance for mis-aimed or dispersed shots to influence friendlies.
Remember that the closer friendlies and enemies are, the steeper your attack needs to be in order to achieve the required delivery angle.
A rule of thumb in a Littlebird is that if you must make an attack with rockets where friendlies are between you and the target, for the best precision and safety, you should wait to begin your diving attack until the angle between your aiming point and the closest friendly is at least five degrees and your distance is either medium or close.
To visualize this, the top of your feet on the pedals are roughly 40 degrees below your point of aim.
The angle between your crosshair and the canopy crossbar is about 20 degrees, like you see here.
Halfway between them is ten degrees, which is plenty of safety margin at close and mid range. At longer range, this is the minimum offset you should use due to ballistic drop being more of a concern further away.
Finally, here's what a five degree offset looks like. This is generally the minimum you should use when at close to mid ranges.
If you're zoomed in and your view is roughly centered with your crosshair, this angle roughly corresponds to the point at which a visible friendly unit would be halfway between the crosshair and bottom of the view.
When you need to approach a target from a lower altitude but need to make the attack in a dive, the best thing to do is to either rise up a bit before reaching the target to increase your delivery angle, or use the running pop technique to sharply climb and then nose over to deliver plunging fire from closer ranges.
Keep in mind that while pure low-level grazing attacks aren't a good idea to use in perpendicular runs, achieving a five-degree separation between the target and nearby friendlies doesn't take a great deal of maneuvering and is almost always viable to permit a safer attack.
The distinction between point and area fire is straightforward - in one of them you're aiming at a specific target, while in the other you're aiming at a specific area.
Point targets are clusters of infantry, vehicles, or anything where you're able to aim directly at and engage the target. Plenty of danger close fits this form and it's rather self-explanatory.
Area targets are often done as a defensive measure where you're being asked to suppress an area that's threatening some action the friendly forces are taking, such as extracting via helicopters. When doing area fire, you manually disperse your shots in order to cover the widest area - typically with rockets. By making rocket runs along a linear area target, you can effectively block the enemy from progressing through that area for a short time. Hitting a treeline while friendlies are being picked up in a nearby field is a good example of this.
For attack helicopters with turret-mounted autocannons, the gun-target-lane is aligned with the direction the gun is pointed, not the aircraft's actual direction of flight. Because of this, the dynamics of how parallel versus perpendicular works are altered somewhat.
While the considerations are the same when flying at and engaging targets, they shift if the helo is orbiting the area or employing from a distant stand off.
Ranging & Ballistics
Due to the ballistics of autocannon rounds, the further away from the target you are and the shallower the angle, the more critical it becomes that every burst is properly ranged by your gunner. If they forget to do this at long range, it's possible for a burst to land hundreds of meters away from where it was intended.
Consider this situation - we engage a target and properly lase it, then shift to a different target without re-lasing. From our shallow perspective this seems ok, but it actually means that we're firing at a (x) meter target with an (x) meter ranging, which causes the rounds to impact friendly positions.
The easiest way to account for these things is to simply always range before firing a burst, especially at shallow angles or longer ranges.
If you want to make it more complicated, remember that you need to ensure you range any time the distance of the target you were last shooting at is further than friendlies, but the one you've shifted to is closer - or vice-versa. You do this because when your ranging is further than the target, your rounds strike high - and if your target is now closer to you than friendlies, "high" can easily translate to hitting friendlies, and the same thing in the opposite direction.
Note that this effect is more pronounced when at shallow angles. To visualize why, let's look at what the beaten zone is when we fire from a low altitude. Given that point of aim, we're going to fire while cycling from 100 meter ranging to 2500. This depth of this beaten zone is happening not because of the natural dispersion of the bullets, but because we're manually giving the targeting computer different ranges to aim for, which changes the elevation of the shots. Looking at this from the air, it's about (x)m deep. With the same point of aim but offset slightly to the side, we'll do the same thing. Comparing the two, the depth of the plunging beaten zone is significantly shorter than that of grazing. Thus, we can infer that any difference in ranging at a steeper angle will translate to less of an impact shift on the ground, and that same error from a shallow angle will result in a larger impact shift.
Note that this offset is relative to the trajectory of the round at that distance. Autocannon rounds tend to be fairly flat out to about a kilometer, but are dropping more steeply past that. Due to this, a ranging error where the target is more than a kilometer away will see the biggest risk for a large impact shift.
Here we can see how ranging from 100 to 600 produces a small offset, whereas 1000 to 1600 is a larger one, and 1900 to 2500 is the largest.
Again, it's much easier and safer to just range before every shot.
When standing off from the target, ideally you position yourself to where you can fire on targets parallel to friendlies. When this isn't possible, the safest thing for friendlies is for you to gain altitude to make your fire plunging as much as possible, for the ballistic reasons we just talked about. If that's not possible, you should avoid firing over friendlies as much as feasible at mid to long ranges and make extra certain that your gunner is continually ranging their targets.
If orbiting, an attack helicopter is no longer concerned with whether their flight path will be perpendicular or parallel to friendlies. Instead, the gunner becomes responsible for whether their gun-target-lane intersects friendlies.
When ricochets are a concern, pilots are responsible for ensuring the gunner ceases fire when friendlies are in the ricochet zone, as they're typically more aware of what portion of the orbit they're currently in. This is mainly a concern when using grazing fire from longer ranges - plunging fire can largely mitigate the issue. When using grazing fire, this cease-fire happens at least once during each orbit of a given target, and the danger area's size is based on where friendlies are relative to that target. A single friendly element might have a small ricochet danger area, while many elements spread out may encompass a much larger portion of the orbit.
If friendly forces are being attacked from multiple directions, orbiting their position from a distance makes it possible to continually engage targets parallel with them. You can keep the gun-target lane from intersecting them while the orbiting motion of the helo continually brings new targets into your lane, as you see here.
When it comes to situations where perpendicular shots seem necessary during an orbit - which is to say you want to shoot at something that places friendlies in the gun-target lane - remember that at closer ranges and shallower angles you can fire at targets beyond friendlies so long as you range properly and don't cut it too close.
Shooting at targets between you and friendlies is a bad idea, particularly when ricochets are factored in, unless you're doing steeply plunging fire.
Gaining altitude and making plunging attacks is the easiest way to simplify the gunnery considerations. Being within close range of friendlies and shooting down at threats around them makes ballistics virtually irrelevant, because the highest ranging and the lowest ranging will only change the point of impact by a matter of meters.
To summarize, the riskiest shooting happens at longer ranges with grazing fire due to the steep trajectory of autocannon rounds, while the safest is at close range with plunging fire.
The high precision required for danger close tends to result in shots being taken from closer ranges for greater accuracy, both from the standpoint of the weapon's inherent dispersion but also from the fact that being closer results in a clearer understanding of the target and greater aiming precision.
Consider the 11-mil dispersion of a typical FFAR - at one kilometer, that's an 11 meter wide area it could land in. In the context of danger close, that's a lot of error margin. However, if you wait to take that shot at 500 meters, you've moved that down to a roughly 6-meter wide beaten zone. If you bring it even closer, at 250 meters you're able to place the rocket in a 3-meter wide beaten zone. Firing from closer ranges increases your risk as a pilot while reducing the risk to those on the ground, and is often the right choice to make.
If using an aircraft that has rockets launching from different pods, keep in mind which one fired last so that you know how to account for the slight offset that will come from one launching from the opposite side.
If you're not sure about your level of precision in a given situation, you can use the technique of walking your rounds towards the target. To do this, you pick a point near the target but on the opposite side of it from friendlies, fire at it, then adjust your fire incrementally closer until you're getting the desired effects on your intended target. Walking fire is commonly used with attack helicopter autocannons due to their relatively high dispersion, but can also be used with other weapons.
Here's where things get really spicy.
To preface this, all danger close has risk involved. The more experienced you are, the more you're able to manage this risk. The technique I'll be demonstrating next is not for babby's first danger close run - this demands high precision and situational awareness, and if you mess it up, you will hit a friendly. If you've never done this, you need to spend a lot of time flying in the editor and practicing this. Don't use this technique unless you know you'll succeed.
Blast masking is the technique of placing rockets such that some sort of hard barrier shields nearby friendlies from the explosion's effects.
Before we show it being used from the air, let's take a moment to simply illustrate how explosions work in Arma. When something like an FFAR detonates, anything within a radius of it will take damage, provided that there's a clear line of sight from the center of the blast to that person.
Here we can see a representation of an explosion. This is roughly equal to the danger area of an FFAR. As we move it around, you can see how different objects essentially cast a shadow - that's the masking we're talking about.
At its most extreme, here's how significant blast masking can be. This person is right on the other side of the wall from where FFARs are impacting, and when each detonates, they're fine. The wall absorbs the blasts for them.
However, there are some complications involved in this. A weak structure like a wooden or corrugated fence won't actually stop the blast, as you can see here. Some wooden sheds are this way as well.
Some structures are weak, or may have been weakened over the course of the mission, and can collapse upon taking damage - damaging those around them even if the actual rocket's blast was absorbed.
Windows and subtle gaps can be rather complicated. A rocket hitting on one side of a building may be able to kill someone on the other side of it if there's a window between the two. With this barn, blasts are blocked by the walls, but if something happens to hit on the side where a small gap exists, the blast can get in and kill someone on the other side.
When using blast masking during danger close, you almost always will be conducting a steep attack and almost always will fire from close range. This gives you the highest precision and the smallest potential for aiming or dispersion errors. Let's look at a few different examples of scenarios where this could occur.
Again, I cannot stress highly enough how this is not a tactic for a novice to employ. It is extremely high-risk if you aren't completely comfortable with your aircraft and accuracy.
This is a simple building mask. Friendlies are on one side of a building, the enemy is on the other, and you can put a rocket on them without hurting your friendlies.
Next we have a corner mask. Same idea.
Here's a wall mask. The thickness of this kind of wall is a reliable indicator that it can handle at least one FFAR going off near it.
And here we have masking with boulders.
So, to summarize: Blast masking is a viable option if you have the proficiency, accuracy, and confidence for it, and the situation makes it usable. It always carries risk, but with practice you'll be able to figure out what those risks are in any given situation and be able to make a proper judgment call.
Offsetting is a technique used with large blast radius explosive weapons like rockets. When a target is so close to friendlies that a rocket hitting it will likely splash those friendlies as well, offsetting can be used to have an effect on the target while minimizing risk to the friendlies. Offsetting requires there to be a clear direction that can be considered as away from friendlies - thus, a vehicle in the center of a squad doesn't allow for it.
Consider this scenario. This BRDM is positioned right by friendlies hidden behind this wooden fence. If the answer we come up with is to use a rocket, the best way to do so is to aim it such that it hits on the other side of the BRDM relative to friendlies, putting them outside of the rocket's blast range and either damaging the vehicle enough that the crew bails, or destroying the wheels and rendering it immobile.
Offsetting can also be combined with masking. Suppose this BRDM has some friendly troops wounded and pinned in a corner. Firing at it directly could easily lead to the rocket being slightly offset and killing friendlies. Any impact to the left or front of the BRDM can potentially hurt those friendlies, so to compensate, we can offset behind it and use the masking of the wall to protect them.
And, of course, you can combine offsetting with masking and walking rounds as well. This is an extreme example of that - getting too close to the vehicle is going to hurt the wounded people nearby, so we want to damage it from as far away as possible. By offsetting on the side of the road and walking the rockets along, we can get an effect without exposing people on the cross street to the blast.
The last thing we'll touch on is confidence. If at any point during the process of making your attack you have doubts about what you're doing, the validity of the shot, whether you can hit precisely enough to avoid friendly casualties, if any of those are the case, DO NOT FIRE. You can always come back around for another pass.
Remember that when you're acting as CAS, the players on the ground are depending on you to know your craft. Mistakes can be costly, and overconfidence can hurt the experience for those you're supporting due to friendly fire or similar. Danger Close is something you need to practice constantly, and being able to deliver it with precision can not only turn the tide for those on the ground, it can be an incredibly cinematic experience for them. You're there to support them, and sometimes that support takes the form of making a situation that much more memorable through precision fire. You're not paying for fuel, bullets, or rockets in the editor, so nothing's stopping you from spending them to develop your proficiency. As always, practice, practice, and then practice some more.
This is dslyecxi, and until next time, take care.