Air-to-air weapons

From UOAF Codex
Jump to navigation Jump to search

Learning objectives

  1. Understand the various systems involved in air to air engagements
  2. Understand the three main types of guidance for air to air missiles (AAMs)
  3. Employ all three kinds of AAMs successfully

Learning files

This document aims at giving a basic overview of the systems you will operate in air to air missions, and is not meant to be a complete guide to combat or substitute in-depth study of manuals and tutorials!

Air to air modes in the F-16

As you might already know, navigation and combat systems are quite tightly integrated in the Viper, and behave slightly differently depending on the selected master mode (MM). It's therefore important to understand the basics of master modes. In this page we will deal mostly with the A/A, missile override (MSL OVRD) and dogfight (DGFT) modes. An important difference between them is that while NAV, A/A, and A/G are master modes, DGFT and MSL OVRD are overrides, meaning that they will "stick" until canceled out by the appropriate hotas command (in other words, all other MM change requests from the ICP will be ignored).

This setup allows a lot of customization (remember, MFD pages can be configured indipendently for each MM from the DTC interface in game); the selected missile and other parameters are saved when switching master modes, so for instance, it's possible to have a long range AMRAAM setup with radar in RWS for A/A mode, medium range AMRAAM in TWS for MSL OVRD, and of course, sidewinders in DGFT. But we will skip these considerations for now.

While it is possible to operate the radar, and to some extent weapon systems, in NAV mode, it is recommended to bring up the A/A MM (at the fence in point at the latest) to be more effective.

In brief, use the A/A MM or the MSL OVRD mode when long range scan and BVR missiles are to be employed, and preferably use DGFT mode when merging. Depending on your joystick/hotas setup, it is highly recommended to bind the three-way DGFT-MSLOVRD-Cancel switch somewhere, along with the uncage button, TMS switch, and cursor slew. Spend some time experimenting with MFD setups in these three modes, a common mistake is to forget to set pages for DGFT mode and lose situational awareness when merging due to loss of SMS and HSD.

Radar modes and employment are covered in another section; we will however review which modes are more suitable to the various munitions in the following section.

Managing inventory: SMS page and the MSL step button

The second crucial system involved in air combat is the Stores Management System (SMS). The SMS is primarily intended to give information about remaining weapons and stores, switching active weapon/pylon, powering up weapons, setting weapon parameters, and to access the selective jettison mode.

Weapon selection can be performed hands-on (that is, via controls on the stick) or hands-off (by pressing relevant buttons around the MFD displaying the SMS page). Weapon selections are preserved between master mode changes, so you can preselect particular missiles types for different modes.

<picture of sms in AA mode>

The buttons around the two MFDs (also known as OSBs) are numbered clockwise starting from the top-left corner. In any AA mode, the SMS page will show current weapon type next to osb #6 <check that>. Pressing the OSB will cycle through air to air weapon types; it is also possible to change the active pylon by pressing OSB#9.

Hands-on selection of weapon types is performed by using the NWS-disconnect button; a short press will cycle hardpoints carrying the active weapon type, while a long press will select the next AA weapon type on board.

The SMS page also has a button to switch seeker mode from WARM to COOL for IR missiles; best performance is achieved when the missiles are in COOL mode. Missile cooling should be part of your fence check: a warm seeker head might result in the missile losing track or not being able to acquire a target when uncaged.

Air to air missiles and their guidance

In order to intercept their targets, all modern AAMs track a source of energy, either in the infrared spectrum (heat) or in the higher frequencies used by RADAR. The three classes of missiles are:

  • Heat-seeking missiles (IR): also known as heaters, generally shorter range (with the exception of more modern variants that can sometimes exceed the range of older generation amraams!), higher maneuverability, fire-and-forget. Examples: Aim-9 (sidewinder) variants, Python, Magic. Good in a merge, can be spoofed by FLARES. Some modern models provide high angle-off launch and therefore give an advantage in turning fights. Brevity: Fox-2.
  • Semi-active radar homing missiles (SARH): guide on radar energy emitted by the launching platform and reflected by the target. Generally longer range and intended for beyond visual range engagements, decent maneuverability, radar lock (single target track, or STT) needs to be maintained for the entire time of flight. Examples: Aim-7 sparrow, Super 530D. Can be defeated by CHAFF and notching, causing the launcher to lose lock. Brevity: Fox-1.
  • Active-radar homing missiles (ARH): also known as long sticks, longest range (with exceptions), medium to high maneuverability, need to be guided to an intercept point after which the on-board radar can track the target on its own (go active, or "pitbull"). Can be defeated by CHAFF and notching if radar lock is dropped before the missile goes active. Brevity: Fox-3.

Generally speaking, the more modern Vipers can carry all three types, but it's very likely that throughout your career you will face theaters where one type or another are predominant due to the factions in play or the timeframe of the campaign. As a rule of thumb, heaters are employed in DGFT mode (and are preselected by default), and work well with ACM radar modes for quick acquisition and firing. However, nothing prevents you from targeting and launching heaters in A/A mode (and is actually preferable in some instances, such as when using the long-ranged Python). ARH and SARH missiles are generally employed in either A/A or MSL OVRD modes.

A note on missiles, radar, and the RWR: launch warnings on the defendant's RWR are set off when the antennas detect an hostile radar switching from search to missile guidance mode. This happens only for SARH missile launches (e.g. sparrow) and for most radar guided SAMs. You will get NO launch warning if a heater or an amraam is shot at you (you will, however, get a very short notice warning when ARH missiles like the AMRAAM or the radar Alamo go active at about 5-8nm from you). It's entirely possible to be shot down by an IR missile and never hear a thing.

AAM employment

We will now go over some tips and procedures for getting the most out of our missiles, covering radar modes, typical engagement flow, and hotas commands. Remember, this is meant to be a general introduction to "good practices" in A/A combat and not a comprehensive tactical guide.

IR missiles

Whether in an '89 campaign or in a modern setting, the IR missile remain probably the most lethal threat you will face. Heaters are fast, maneuverable, and stealthy; they can be launched without giving off any warning whatsoever, and the AI (not to speak of humans) will often do their best to sneak up from below and send one up your tailpipe.

The best defense against IR missiles is to spot the launch early, deploy a healthy amount of flares, and break hard into the missile to bleed its energy and provide a difficult tracking solution. Mutual support is paramount in dealing with IR equipped enemies.

Most IR missiles are represented in game by a diamond on the hud, indicating the missile's line of sight (where the seeker is pointed). The missile's seeker head can be in one of two states, caged or uncaged. When caged, the diamond will be right on or very close to the boresight (or gun) line; it will, however, slave to the RADAR line of sight when in any tracking mode (single tracking or SAM) and can also be cued with the HMCS in modern variants (look-and-shoot) for high angle off-bore shots.

Uncaging the seeker head with the MAN Range/Uncage hotas button causes the diamond to grow bigger and start "wandering" around the hud and eventually off it. When uncaged the seeker will latch on to sources of sufficient IR energy (heat); typically this is accompanied by an increase in pitch/beeping rate of the audible cue (growl) associated with IR missiles. The missile can be employed this way to perform a stealthy engagement without using the radar (remember that IR missiles will not set off the launch warning in the target's RWR in any case).

The seeker head will in any event uncage on launch; it's recommended however to uncage right before firing even when the seeker is slaved to the radar target. The seeker head can be re-caged via the same button. Keep in mind heaters can be rear-aspect (only able to track the heat signature from a rear aspect to the target) or all-aspect (able to engage from the front and sides as well). <insert table>

Typically, after acquiring a bandit visually or on radar, a short range engagement consists of the following steps:

  1. Set up the intercept and sort targets if distance allows, or perform an appropriate maneuver for your element if at very close range to set up the dogfight
  2. Bring up the DGFT mode by HOTAS commands
  3. Confirm IR missile is up by audio cue
  4. If FCR operative and time allows, select an appropriate ACM submode (90% of the time it will be vertical scan, selected by pressing TMS down once), or use the HMCS to achieve an off-boresight lock (hold TMS up to show the circle and check the seeker head slews the target when releasing TMS up)
  5. Maneuver to obtain a firing position, depending on the weapon (rear aspect or all aspect)
  6. If using radar, confirm lock and tracking and uncage; otherwise, maneuver to put the seeker head on target and uncage the seeker for a "manual" lock
  7. CONFIRM YOU HAVE POSITIVE ID THAT THE TARGET IS, IN FACT, ENEMY, and that the seeker head is uncaged and tracking the correct target (heaters don't easily drift off their intended target but blue on blue have and will happen if you don't uncage or shoot in a very close furball)
  8. Call out Fox-2 over flight comms; fire the weapon

Of course, with all-aspect missiles it's very possible to splash your targets with a frontal shot on the merge and simply blow through, but never get complacent and always clear your six and your wingman's. It's also a good idea to preselect a flare-heavy program for the merge, to defeat a similar shot from your opponent. If you spot an enemy launch in the merge, immediately call it out and perform an appropriate defence.

Semi-active homing missiles

For simplicity's sake we will focus on the AIM-7 Sparrow missile as it is the most common SARH missile you will employ in Falcon. Technically speaking, the sparrow is a capable missile, not to be underestimated; however, it suffers from one simple drawback: it relies on a valid lock throughout the entire intercept. This is easier said than done, as experience showed us that the radar, especially in older blocks that tend to use the sparrow, can be quite easily spoofed by exploiting the "doppler gate", or "notching".

Scanning radars rely on doppler shift (the change in frequency between the emitted and received radio waves) to differentiate between targets and ground clutter, as well as determining their closure rate. A target flying on a 90° offset to the emitter will essentially show no doppler shift, rendering itself a lot more difficult to distinguish from ground or false returns. In short, this means that flying on a track perpendicular to the bandit's bearing can often force their radar to lose its lock on you, defeating any SARH missiles relying on that lock. This maneuver is also called beaming (from "putting the radar on the beam", or your 3 o'clock - 9 o'clock line). It's very important to note that to defeat a SARH missile, you need to beam the launching aircraft, not the missile itself! We will talk more about this difference in the ARH missile section.

Besides the defensive considerations, this also has an important impact on employing SARH missiles offensively. Since your target will receive a launch warning as soon as the missile leaves the rail (and, if they are somewhat experienced, they will indeed be already expecting and preparing for it), they will often immediately beam you, dispensing a good serving of chaff to further confuse your radar. This very often results in a dropped lock and a wasted missile. However, if this happens, you still hold the advantage: the bandit is now beaming you, therefore is in no position to launch a missile of his own, and if he did launch one previously, it's most definitely defeated (unless it's an ARH and you don't change heading, but we'll talk more about this later).

Sparrows are therefore not necessarily a good "kill" missile, against capable opponents, but a very good offensive weapon nonetheless, as they can force an adversary on the defensive and allow you to close in for a follow up shot or a close range engagement with heaters.

However, if the bandit does not beam you, he's probably trying to crank hoping that you will make a mistake and fly in straight into his own missile. This is maybe the worst mistake you can make in a BVR engagement, and we'll see why a little further down the road, after we cover ARH missiles.

A typical Sparrow engagement looks like this:

  1. Acquire bandit on radar, in RWS or TWS mode
  2. Sort targets within the flight
  3. Soft lock (SAM mode) your assigned target, assess distance, closure rate, altitude, and aspect. Do not go in STT (double TMS up) yet! If you have range, there's no reason to start getting target fixated with single target tracking
  4. Monitor your target and the rest of his flight as distance decreases, and keep scanning the instruments as well as outside the canopy
  5. As the target approaches the far end of the DLZ (launch distance bracket), you'll need to decide whether to launch at max range to put him on the defensive, or to wait for a higher PK shot
  6. A few seconds before the target falls in the desired range, switch to STT mode (TMS up again). The hud will remind you to do so with a "GO STT" mnemonic just under the TD (target designator) box
  7. Call out Fox-1 and target bullseye over Flight or Package comms if appropriate
  8. Fire the missile, and immediately crank left or right reducing power slightly if necessary
  9. Keep the target on or close to the left or right edge of your radar scope, to maintain lock and reduce closure rate
  10. Monitor target aspect and if he tries to notch, be prepared to turn back into him and scan his last known position
  11. Monitor the time to impact timer below the DLZ on hud, scan for impact

As we have seen above, a Fox-1 launch is often not the end of an engagement, but a very important phase of the BVR to WVR transition. Practice how your enemies typically react when fired upon and anticipate what's going to happen. Am I about to lose lock? Did I turn too much or too little? Did he fire back or not? Should I break away and let the other element press on?

ARH missiles

Active Radar missiles are the kings of modern BVR combat. They are big, fast, reasonably maneuverable; they can reach far out (sometimes VERY far... reference the AIM-54C with its 60+ nm range!) and since their introduction, have revolutionized air combat. Similarly to their SARH counterparts, they require a radar lock to guide on their targets, but with an important difference: they do not track the reflected radar energy, but are steered by datalink commands to an intercept point, where the smaller on-board radar takes over to conclude the engagement. This means that a radar track is not required all the way until the target is splashed, and can be dropped as soon as the missile reaches the so-called Pitbull point, approximately 5-8 miles from the target.

As mentioned briefly above, you will NOT get a launch warning when fired on with an active radar missile, since the shooter's radar does not behave any different when guiding this kind of weapon. It's very important then to know your enemy, and know if there will be modern fighters equipped with this kind of missile; due to the ranges involved, spotting the launch can be very difficult, so you should be prepared to "read" the situation as it develops and defend preemptively, or on a hunch, if necessary. When they go active, ARH missiles show up as a flashing, circled M on the RWR, so if you see one, it's time to break hard, as the missile is in terminal guidance, very close and coming in fast and from above.

Remember that in this case, beaming the launching aircraft is perfectly useless. There's no notching an ARH seeker; the only defence is to either run and climb, hoping to outrun the missile if you have reason to believe it was a long range shot, or to beam the missile (again, not the launching bandit) and break hard into it to defeat it kinematically. This is often very difficult to do: in the terminal phase, the rocket motor will have already burned out, so there will be no visible smoke trail to help you see the incoming missile. Most of the time you will have to time the break turn manually, judging by the time elapsed since the missile went active, or by how close the RWR icon is to the center.

Another important feature of ARH missiles is the possibility to launch and guide multiple munitions on different targets at the same time, using the track-while-scan (TWS) radar mode. This is an immense advantage over older generation fighters, allowing a two-ship to splash half a squadron of migs without breaking a sweat, but can put a lot of pressure on more advanced fighters as well. Having multiple munitions go active on your entire flight at the same time is not a pleasant experience.

Finally, a word of caution: the AMRAAM will guide on whatever happens to be in front of it at the time it goes active. Moreover, if a radar lock is lost while guiding to the intercept point (missile not yet Pitbull), it will go ballistic and eventually start looking for something to guide on. This means that firing an AMRAAM in a furball (a situation where friendlies are merged, or in a dogfight, with bandits) can easily result in the missile locking up a different target than the intended one; this usually ends up in blue-on-blue, and is therefore considered a Very Bad Thing to do. Never fire an AMRAAM if you are not entirely sure there's no friendly contact within about 10 miles of the target.

Proper BVR tactics are a rather complex subject, but we'll take an example of a common engagement you can face in BMS: engaging a four ship in a two-ship escort or CAP flight.

  1. Select A/A or MSL OVRD mode
  2. Acquire bandits on radar in RWS or TWS mode
  3. Switch to TWS mode, center on the enemy group, build up the picture
  4. Sort targets within the flight; in this example, lead takes the two right bandits, 2 takes the two on the left
  5. Bug the first assigned target
  6. Check range indexer (DLZ) on HUD for fire solution
  7. When approaching desired range, pitch up to the indicated loft angle (above the DLZ), center the dot, and fire the first missile
  8. Call out Fox-3 and target(s) bullseye over Flight or Package comms if appropriate
  9. Bug second target, manually or via the hotas shortcut (TMS right short) to cycle through targets
  10. Repeat as necessary (but do not call out each missile launch!)
  11. Crank in the briefed direction to put the contacts on the edges of the radar scope, reduce power as necessary to reduce closure rate
  12. When the last missile goes pitbull (counter below the DLZ - M05 means five seconds to pitbull, T03 means three seconds to impact), break away and regain separation to avoid merging into a dogfight

AIM 120 SMS settings

The radar model for AMRAAMs now includes HPRF (Husky) mode for favorable target geometries.The missile will activate the seeker well before the normal MPRF (Pitbull) range and attempt to track.
HPRF is better at tracking high aspect targets with high closing range rate. Datalink guidance will continue up to MPRF unless the pilot commands a snip (drops the radar track) before that time.
During HPRF with host DL guidance, the missile will use the best tracking solution available (either seeker or host DL guidance).
HPRF and MPRF activation are now entirely based on range to target (used to be time-to-run based). Ranges coded are educated guesses.

The variables are:

  • AspectSelectorSize – HPRF requires target aspect to be within this many degrees of 180.
  • HuskyMinClosure – HPRF will not activate unless range rate is higher than this threshold
  • HighAspectBomberHusky – Select LARGE target (AIM120 SMS page) to use this as HPRF range gate
  • HighAspectFighterHusky – Select MED or UNKN target (AIM120 SMS page) to use this as HPRF range gate
  • BomberPitbull – Select LARGE target (AIM120 SMS page) to use this as MPRF range gate
  • FighterPitbull – Select MED or UNKN target (AIM120 SMS page) to use this as MPRF range gate

Note: you can select SMALL in the SMS page. Doing so doesn't make a lot of sense in Falcon4 since this is apparently intended for targeting small RCS targets although it might be useful against helicopters.
If you do choose small, MPRF ranges are reduced by around a third compared to MED.