Combat/Aerial Combat

Aerial Combat refers to one of the stages conducted during combat in the game, conducted after detection and before Support Expedition, Opening Torpedo Salvo (if condition for them to happen are fulfilled), and display of the engagement form.

In Aerial Battle nodes, after finishing Aerial Combat rundown for the first time, the engagement form will be displayed a second process of Aerial Combat will occur, with the potential exception of the contact phase.

In Night Battle nodes, Aerial Combat usually does not occur. In some rare cases when Night Battle nodes can conditionally be turned into Day Battle, the Aerial Combat phase will start immediately without a detection phase.

If Jet plane(s) is(/are) carried by carrier(s), then an additional jet assault would occur before the regular opening air strike phase.

For the mechanism applied on aircrafts in support expedition, land-based aerial support, shelling phase and anti-submarine operations, please refer to respective pages for further information.

Note that, unless otherwise specified, all the numerical values on this page are only applicable to the player's side.

Overview
(The following table is sourced from this Japanese KanColle wiki page, but it is out of date compared with the original, and it needs further explanation. For a given combat role (column), aircraft types (rows) marked ◯ are supposed to be generally more effective than those marked △. For fighter combat, types marked × do not take part at all and are not affected.)

Fighter Combat
$$F_{\text{Power}} = \sum^\text{All Slots} \left \lfloor \sqrt{N} \cdot \left ( E_{\text{AA}} + E_{\bigstar} \right ) + P \right \rfloor$$

Where:
 * $$F_{\text{Power}}$$ is the total Fighter Power of the fleet.
 * $$N$$ is the current plane count (slot size) of that slot.
 * $$E_{\text{AA}}$$ is the plane's displayed AA stat.
 * $$E_{\bigstar}$$ is the plane's improvement bonus to the AA stat.
 * $$E_{\bigstar} = \bigstar \cdot 0.2$$ for fighters, $$E_{\bigstar} = \bigstar \cdot 0.25$$ for (fighter-)bombers
 * $$P$$ is the plane's Aircraft Proficiency bonus.

Notes: Note: For the users who are aware of the terminology switch between AD and AI, this was caused by a mistranslation. The correct order is AD > AI.
 * Fighter planes, and specific Torpedo / Dive / Seaplane bombers with an +AA stat participate in the Fighter Combat.
 * Recon planes (carrier based or seaplane recon) will NOT participate in Fighter Combat.
 * Aircraft Proficiency is factored into Fighter Power on top of the above formula. The exact formula is under investigation.
 * The allied fleet and enemy fleet's Fighter Powers are compared to determine the result of Fighter Combat:


 * EFP: Enemy Fighter Power, FP: Fighter Power. Abbreviated to save space.
 * This calculation does not take into account any anti-air weaponry equipped on ships. Carrier anti-air stat is also not considered.
 * The percentage of planes shot down was originally believed to apply for both sides' respective outcomes, however it is now under re-checking. If it is true, then for example, securing Air Superiority means allied planes shoot down up to 80% of enemy planes, and the enemy under Air Denial will shoot down up to 40%.
 * Planes shot down are calculated per slot, rounded down.
 * As this is applied per slot, 80% of one enemy bomber group can be shot down while a second has 0% shot down.
 * Planes loaded on moderately/heavily damaged carriers can still join this stage of fighter combat.
 * Even if allied planes secure Air Supremacy, planes can still be lost (up to 10%), and the subsequent anti-air defense stages can eliminate more bombers.
 * If the enemy fleet launches no fighters and any planes are launched from either side, the result defaults to Air Supremacy. If both sides launch no planes, then the rest of the battle is treated the same as if Air Parity was achieved.
 * Contact can't be triggered in Air Incapability
 * Night Contact can be triggered in most case when it is not Air Incapability, however it can't be triggered when it is under Air Parity, with the exception of during PvP or when it is a night battle node then it still Night Contact still can be triggered even if it is under Air Parity state.
 * Artillery Spotting can only be triggered with at least Air Superiority.
 * If fighter combat occured but the fighter power of both sides are zero, then friendly fleet side would get Air Supremacy automatically.
 * Not all shot down roll result carry same probability. For instance, in the situation of AS+, enemies are most likely to lost 30%-70% planes, and is less likely to lost close to 0% or 100% of all of their planes.

Contact
Contact takes place during the Aerial Combat phase. It increases bombing damage for all allied bombers. When successful, an image of the squadron performing contact is shown in the opposing fleet's formation indicator, with the text "触接中". Different types of planes have different trigger rates. They are roughly estimated as (if only one is equipped):
 * Trigger conditions:
 * More air control than Air Incapability
 * At least one carrier scout plane, seaplane scout, or torpedo bomber equipped.
 * Seaplane bombers, Type 3 Spotter, and Ka-type Autogyros cannot perform contact.
 * It's thought that each carrier scout plane, seaplane scout, and/or torpedo bomber slot equipped is given a chance to trigger contact. Once successful, the bonus applied is chosen at random with weighting preferential towards higher modifiers from all eligible equipped planes.
 * Note that after contact is triggered, it is another random process to decide which plane should be responsible for contact and probability listed here are not relevant to that part.
 * Too few planes in a slot would negatively influence contact trigger rate.
 * There's a hypothesis about contact rate related to LoS.

Contact Trigger Chance
The process that determines whether or not Contact triggers consists of two parts.

Stage 1: Contact Trigger
In this stage, the system merely determines whether Contact triggers at all.

Which plane triggers it has not been determined yet.

Each plane has its own "trigger rate", which according to current research is based on the plane's LoS and the size of the slot it's in. The trigger rates of all planes in your fleet are then added together to determine the chance of successful Contact. A provisional approximation formula is given by:

$$P_{\text{Contact}} = \sum^{\text{All Slots}} \left ( \sqrt{N} \cdot E_{l} \cdot E_{m} \cdot C \right )$$

Where:
 * $$P_{\text{Contact}}$$ is the overall chance of successful Contact
 * $$N$$ is the current plane count (slot size) of that slot
 * $$E_{l}$$ is the plane's displayed LoS stat
 * $$E_{m}$$ is the plane type modifier.
 * For Carrier-based Reconnaissance and Reconnaissance Seaplanes, $$E_{m} = 0.04$$
 * For Torpedo Bombers, the value would be much smaller.
 * $$C$$ is the Air Control Status.
 * For Air Supremacy (AS+), $$C = 1$$
 * For Air Superiority (AS), $$C = 0.6$$

If Contact is determined to be successful, the system proceeds to Stage 2. If Contact fails, nothing else happens.

Stage 2: Contact Plane Selection
Now that Stage 1 has been successful the system has to determine which plane is going to trigger Contact. The priority among planes is as follows:
 * Higher Accuracy stats mean higher priority
 * If two or more planes have the same amount of Accuracy, the selection process goes through them from top to bottom, start from the first ship first slot then first ship second slot and end with the sixth ship last slot.

The system goes through each plane from top to bottom priority until either one is selected or none is. Current data suggests that a plane's selection rate is determined by its LoS stat. Another provisional approximation formula is given by:

$$P_{\text{Select}} = E_{l} \cdot 0.07$$

Where:
 * $$P_{\text{Select}}$$ is the selection rate of a given plane
 * $$E_{l}$$ is the plane's displayed LoS value

If no plane is selected in the end, then Contact is cancelled and doesn't trigger.

Contact Damage Modifier

 * The damage increase depends on the +accuracy bonus of the squadron performing contact.

Fleet Anti-air Defense
The Fleet Anti-air Defense system was updated on 14 November 2014, alongside the addition of the Anti-air Cut-in system. It was then patched on 26 June 2015 to fix several bugs.

System Mechanics

 * Each enemy bomber slot is assigned at random to a defending ship.
 * Those ships then, for each assigned enemy slot, have two approximately 50% concurrent but independent chances to shoot down enemy planes.
 * The first chance (termed Proportional Air Defense) can shoot down a number proportional to the initial size of the enemy bomber squadron after anti-bomber combat.
 * The second chance (termed Fixed Air Defense) can shoot down a fixed number of enemy bombers determined by stats and equipment only.
 * Simply speaking, There's a 25% chance you can trigger both Proportional and Fixed Air Defense, 25% only trigger Proportional, 25% only Fixed, and 25% none of them being triggered, for every slot.
 * Finally, one bomber from each enemy squadron will always be shot down regardless of success or failure of the previous two chances for friendly ships on abyssal. If AACI was committed, then it would also shoot down a specific amount of planes per slot according to the AACI's API type.

The numbers of planes shot down are given by the equations below:

$$S_{\text{Proportional}} = \left \lfloor \frac{ f ( \hat{A} ) \cdot C }{400} \cdot N \right \rfloor$$

$$S_{\text{Fixed}} = \left \lfloor \frac{ \big ( f ( \hat{A} ) + \lfloor \hat{F} \rfloor \big ) \cdot K \cdot C }{10} \right \rfloor$$

Where:
 * $$S_{\text{Proportional}}$$ is the number of planes shot down by Proportional Air Defense
 * $$S_{\text{Fixed}}$$ is the number of planes shot down by Fixed Air Defense
 * $$\hat{A} = A_{\text{Base}} + \sum^{\text{All Slots}} \bigg ( \left ( E_{m} \cdot E_{\text{AA}} \right ) + \left ( E_{\bigstar} \cdot \sqrt{\bigstar} \right ) \bigg )$$
 * $$\hat{A}$$ is the adjusted AA value of the ship, following the formula above.
 * $$A_{\text{Base}}$$ is the basic AA value of the ship; that is, its numeric AA value without factoring equipment.
 * $$E_{m}$$ is the equipment type modifier (see: Equipment Modifiers).
 * $$E_{\text{AA}}$$ is the equipment's displayed AA stat.
 * $$E_{\bigstar}$$ is the equipment's improvement modifier to adjusted AA.
 * High-Angle Mounts: 3
 * Air Radars: 0
 * Anti-Air Guns: 4
 * $$N$$ is the current plane count (slot size) of the targeted slot.
 * $$\hat{F} = 1.54 \cdot \left \lfloor F \cdot \sum^\text{All Ships} \bigg \lfloor \sum^{\text{All Slots}} \left ( \left ( E_{fm} \cdot E_{\text{AA}} \right ) + \left ( E_{f\bigstar} \cdot \sqrt{\bigstar} \right ) \right ) \bigg \rfloor \right \rfloor$$
 * $$\hat{F}$$ is the adjusted AA value of the fleet, following the formula above. This is only added to the adjusted AA value for Fixed Air Defense, as a bonus.
 * $$F$$ is the formation modifier. For Combined Fleet, the following modifiers are applied:
 * Cruising Formation 1: 1.1
 * Cruising Formation 2: 1.0
 * Cruising Formation 3: 1.5
 * Cruising Formation 4: 1.0
 * $$E_{fm}$$ is the equipment type multiplier for fleet AA (see: Equipment Fleet AA Multiplier), not to be confused with the regular equipment type modifier.
 * $$E_{f\bigstar}$$ is the equipment's improvement modifier to fleet AA.
 * High-Angle Mounts: 3
 * Air Radars: 1.5
 * Anti-Air Guns: 0
 * $$f( x ) = q \cdot \left \lfloor \frac{x}{q} \right \rfloor$$
 * If the ship is not equipped with anything, $$q = 1$$
 * If the ship is equipped with something, $$q = 2$$
 * $$\left \lfloor x \right \rfloor$$ is the floor function; that is, the rounding down of input $$x$$
 * $$K$$ is the Anti Air Cut-In multiplier to Fixed Air Defense, default 1 if no AACI is triggered. This is a modifier independent of the flat shootdown caused by AACI, and depends on the API identity of the triggered AACI. When AACI is triggered, this multiplier is applied individually for each ship in the fleet, not only the ship performing AACI. See the Anti Air Cut In table in the respective section for a list of K-values corresponding to different AACI API numbers.
 * $$C$$ is the Combined Fleet modifier. Defaults to 1 if the fleet is not combined.
 * Main Fleet: 0.72
 * Escort Fleet: 0.48

To see this formula in use, click below.

Abyssal Anti Air Formula
$$S_{\text{Proportional}} = \left \lfloor \frac{ \lfloor \hat{A} \rfloor }{400} \cdot N \right \rfloor$$

$$S_{\text{Fixed}} = \left \lfloor \frac{ \lfloor \hat{A} + \hat{F} \rfloor }{10.6} \right \rfloor$$

Where:
 * $$\hat{A} = 2 \cdot \sqrt{A_{\text{Base}}} + \sum^{\text{All Slots}} \left ( E_{\text{Modifier}} \cdot E_{\text{AA}} \right )$$
 * $$\hat{F} = 2 \cdot \left \lfloor F \cdot \sum^\text{All Abyssals} \bigg \lfloor \sum^{\text{All Slots}} \left ( E_{\text{Multiplier}} \cdot E_{\text{AA}} \right ) \bigg \rfloor \right \rfloor$$

Formation Modifiers

 * Modifiers for Combined Fleet Formations are to be investigated.

Equipment Modifiers

 * There may be other types of equipment with modifiers that affect the air defense equations which are not yet known.

Anti-Air Cut-In

 * This section mainly describe the effect of Anti-Air Cut-In. For perspective on how to setup Anti-Air Cut-In, Please read the Anti-Air Cut-In tab in Combat section of the page.

Certain equipment combinations (see below) will provide a chance for an Anti-Air Cut-In (AACI) during the Aerial Combat Phase. When activated, the cut-in animation (shown on the right) appears before engaging the enemy fighters. However, the effect of an Anti-Air Cut-In does not affect the resulting air control state (AS+, AS, Air Parity or Denial), and calculation-wise, it only takes effect after fighters engage bombers in air combat. With an AA Cut-In and a good anti-air composition, it is sometimes possible to obliterate all incoming bombers before they inflict any damage, and even prevent enemy carriers from attacking during the shelling phase (due to having 0 bombers left).

Although several ships can be equipped with an AACI setup in one fleet, only one ship can perform an AACI during the aerial phase. The number of planes shot down is dependent on the ship performing the AACI and their equipment. Bringing more AACI capable ships will NOT increase the number of planes shot down via AACI.

Akizuki-class destroyers and Maya Kai-2 have a hidden bonus to certain AA Cut-in setups which increases the effectiveness tremendously.

In PVP Exercises, opposing fleets can do AACI, but the animation is not shown.

There is no known instance of Abyssal AACI.

Trigger chance of AACI is determined both by the API type as well as the effective AA value of the ship using it. Fleet AA does not affect trigger chances. Luck does not affect AACI trigger rate.

Be noted that AACI effects are added on to the regular anti-air fire of your fleet, thus anti-air stat of other ships or/and equipment on those ships in your fleet would still matter even if an AACI has been activated.

Equipment, API
The following table summarized information known so far about what type of equipment would trigger AACI, trigger rate, and effectiveness.
 * [[File:CDMG.png]] and [[File:Customized HA plus AAFD icon.png]] are provisional icon for CDMG and Akiguns
 * Built-in HA mount means a single equipment piece that combines a HA Mount with a built-in AAFD. ONLY the following pieces of equipment satisfy this requirement:
 * 10cm Twin High-angle Gun Mount + Anti-Aircraft Fire Director ("Akiguns")
 * 12.7cm High-angle Gun + Anti-Aircraft Fire Director
 * 90mm Single High-angle Gun Mount
 * 5inch Twin Gun Mount Mk.28 mod.2
 * CDMG refer to any of the following equipment:
 * 25mm Triple Autocannon Mount (Concentrated Deployment)
 * Bofors 40mm Quadruple Autocannon Mount
 * QF 2-pounder Octuple Pom-pom Gun Mount
 * Except AACI Type 1/2, so far, only Air Radars have been found to satisfy the requirement for a radar in all other types AACI. It is not clear if Surface Radars can potentially trigger an AACI if they have an AA stat, though at present there are no such radars in existence.
 * If a ship fulfils multiple requirements, the API which shoots down the most planes per slot will be activated
 * For instance Akizuki with 2 akiguns and a T13K air radar fulfills the requirements of AACI with API values 1, 2, 3, 5, 8 - the only API that will ever trigger is 1.
 * It is impossible for an Akizuki-class to ever trigger API 5 or 8 as any equipment setup that will trigger these will also trigger 1 and 2 respectively, which will override it.
 * Exceptions exists:
 * For instance, AACI with the API values of 7 and 8 can both be triggered by the same ship if she has fulfilled both requirements.
 * Another instance of that happening is with API values 19 and 20. Kinu Kai Ni can trigger API 20 as well if she fulfills the requirements for API 19.
 * The same thing happens with API 8 and 20.
 * If multiple ships fulfill AACI requirements, the one with the highest API number will be triggered first
 * While Akiguns are the most powerful guns Destroyers may equip, non-Akizuki-class Destroyers equipped with an API 5 build will override an Akizuki-class Destroyer's API 1 AACI; to avoid this, non-Akizuki-class Destroyers sortied in the same fleet as Akizuki class Destroyer(s) should not equip Air Radars.
 * AACI Type 18 is apparently an exception
 * While API 14 formerly shot down 3 planes per slot, it was buffed on 19/01/2016 and API 15 was added. The number of planes shot down per slot for API 14 and 15 is unknown at present and currently under investigation.

Opening Air Strike

 * Bombers attack ships in this stage
 * If Detection fails, this stage will not occur.
 * Each slot's planes would target one ship and attack for one time.
 * $$Damage=\lfloor (\lfloor cap_{150}\{(25 + P\sqrt{N})R\}C_v \rfloor T-A)L \rfloor$$
 * $$P$$ refer to bombing or torpedo value
 * $$N$$ refer to number of plane in the slot
 * $$R$$ is a fixed $$1.0$$ for Dive Bombers, but is a random $$0.8$$ or $$ 1.5 $$ for Torpedo Bombers/
 * The probability for Torpedo Bombers acquiring an $$1.5$$ multiplier in 1-1-A is around 50%
 * $$cap_{150}(x)$$ refer to the attack power cap, see Combat page for detail.
 * $$C_v$$ refer to Critical hit bonus from Aircraft Proficiency system. See Combat page and Aircraft Proficiency for details about its effect and etc.
 * If you bring more proficient planes, the rate to trigger it would increase.
 * With max proficiency Suisei Model 12A on 3 slot of a ship, critical hit rate is around 20%.
 * $$T$$ refer to contact multiplier, $$1.0$$ if contact failed
 * $$A$$ refer to enemy armor, see Combat page for detail.
 * $$L$$ refer to ammo modifier, see Combat page for detail.
 * No effect from engagement/formation/ship health when they launch planes/morale/fatigue on firepower or accuracy.
 * Affected by the Aircraft Proficiency system.
 * Carrier's level and plane's accuracy stat do not affect this stage.
 * Accuracy is around 80% against destroyers in 1-1-A.

Jet Assault
If any carriers on either side are equipped with jet-powered aircraft, a Jet Assault phase will commence before the main aerial combat phase and land-based airstrike phases. The mechanics of this phase are identical to the standard air combat phase, however only jet aircraft on both sides will be able to participate.

Examples
