Land Base Aerial Support

Introduction
Land Base Aerial Support (abbreviated as LBAS) is a system introduced in the May 2nd-3rd 2016 update along with the Spring 2016 Event, which enables seaplane, carrier-based, and land-based aircraft (but not Autogyro/Liaison Aircraft) to be launched from an air base to assist the fleet during sortie in certain maps.

Prerequisites
The prerequisites for unlocking land bases vary from event to event. Typically, admirals will initially gain access to just one base at first, with other bases being unlocked gradually later. In the Spring 2016 and Summer 2016 events, land bases were unlocked progressively one-by-one by clearing certain event maps, to a maximum of three bases. For Fall 2016, all players had by default 2 bases unlocked, the third base was unlocked by clearing a certain map during the event.

World 6 land bases are unlocked through a chain of quests which yield items required to establish bases. Two bases are available for free from these quests, while the third base item can be purchased from the Item Shop. These bases are different from limited-time event bases.

How to Use
First introduced in Spring 2016 Event, players were able to establish an air base from which support aircraft could be launched. Usable aircraft included carrier-based aircraft and seaplanes, as well as land-based aircraft that are exclusive to this support system.

In certain maps where land base aerial support is available, players may activate the support and assign aircraft to the airbase as shown here:

When land base aerial support is active for that map, a mark will be displayed below the sortie button.

At the start of the sortie, players can designate up to two target nodes per airfield where aerial support will be performed. Selecting a single node twice will concentrate aerial support in one location. In order for the node to be clickable, a node must be within a certain range of the land bases. For Spring 2016 Event maps, node ranges are referenced from the starting point of the sortie (or for Map 6-4, the western starting point). This was changed to relative distance from the airbase symbol from Summer 2016 Event onwards.

When the player's fleet reaches the node where the aerial support is requested, a land-based air battle will take phase before the carrier-based air battle, the support expedition, and the initial torpedo strikes. This allows them to weaken the enemy fleet and their air power, allowing players to secure air control more easily.

However, starting from Fall 2016 Event, each map that supports LBAS may have a base limitation, which limits how many bases may perform Sortie support on that map. If the number of Sortie support bases exceeds the limit, excess sortie bases will be relegated to standby.

Similar to shipgirls, planes assigned to the airbase needs to be resupplied as well.

The refueling process for aircraft is similar to refueling the shipgirls. However, the right box resupplies bauxite instead of ammunition. Use drag and drop to remove a plane from air base slots.

Caution: Removing a plane from an air base will make that plane unavailable for 12 minutes while it is being "relocated"

Properties of different types of aircraft in LBAS
Aircraft that can be assigned into an air base can be divided into the following categories:
 * [[File:BluePlane.png]][[File:RedPlane.png]][[File:GreenPlane.png]][[File:YellowPlane.png]] Carrier-based Aircraft : Can be equipped on both air base and aircraft carriers. May be further categorized as fighter, bomber (Dive/Torpedo) and recon aircraft.
 * Seaplanes : Can be equipped on air base, cruisers, and battleships. Generally have lower performance compared to carrier-based aircraft.
 * [[File:Large Flying Boat Icon.png]] Flying Boats : Can only be equipped on a flying boat tender (such as Akitsushima) or air base. Has enormous flight range. Add extra range since Summer 2016 Event.
 * [[File:Land-based Attack Aircraft Icon.png]] Land-based Attack Aircraft : Has greater flight range than carrier-based aircraft, but cannot be equipped on shipgirls.
 * [[File:Interceptor Fighter Icon.png]] Interceptor Aircraft : Purpose-built aircraft for intercepting bombers that are stationed in the air base. Has lowest flight range.

Autogyro/Liaison aircraft cannot be assigned to land bases.

Options
There are 5 options in the airbase menu as shown below. Clicking the board will flip through these options:



Those options are:
 * 【出撃】 Sortie


 * Allows the player to choose nodes for land base support.
 * 【防空】 Air Defense


 * Protects air bases from enemy air raids.
 * 【退避】 Retreat


 * Prevent planes being damaged by enemy air raids.
 * 【休息】 Rest


 * Increases morale recovery speed
 * Bauxite natural regen speed would be halved if you set your squadron to this status. (i.e. 1 bauxite regen every 6 minutes instead of 3.) Does not affect those who have more bauxite than the natural regen cap.
 * 【待機】 Standby
 * Increases morale recovery rate

Choosing Sortie will allow players to choose nodes for land base support. Choosing Air Defense will skip the choosing node process but will allow interception of enemy air raids, so Air Defense mode should be coupled with high AA aircraft and interceptors stationed at the land base. The remaining options will cause the base to not take any actions during sortie.

All bases that are set to Sortie but not actually sent to perform support are defaulted to Standby.

Cost

 * Putting planes onto a land base consumes bauxite.
 * Check these links to see each plane's cost:
 * Fighter, Torpedo Bomber, Dive Bomber, Seaplane, Land-based Attack Aircraft, Interceptor Fighter, Reconnaissance
 * Note that the cost listed in these tables are the cost for equipping 1 plane, but each slot in your land base can have 4 planes (for reconnaissance planes) or 18 planes (for other planes, since 2016 summer event), so you'd need to multiply the listed cost by 4 or 18 respectively to get the equip cost per slot.
 * Some planes, like Shinden Kai, Prototype Seiran, and Type 1 Land-based Attack Aircraft cost more than a hundred bauxite just by putting them into the air base.
 * (Updated 8/13) Sortieing planes consumes fuel and ammo.
 * Land-based attack aircraft consume 27 fuel and 12 ammo per squadron.
 * Scouts consume 4 fuel and 3 ammo per squadron.
 * Other aircraft consume 18 fuel and 11 ammo per squadron.
 * The actual formula depends on the number of planes in the squadron before sortie: let the amount of plane in the squadron be p:
 * Land-based attack aircraft consume 1.5p fuel and 0.66p ammo per squadron
 * Other aircraft consume p fuel and 0.66p ammo per squadron
 * Resupplying planes consumes fuel and bauxite.
 * Fuel consumption is equal to 3 times the number of planes lost, and bauxite consumption is equal to 5 times the number of planes lost

Limitations

 * Each aircraft has their own "flight range", which indicates the combat radius of the aircraft. Aircraft that have low flight range will not be able to reach map nodes that are too far away from their air base. See Distance Calculations for details. In most cases, land-based bombers have greater combat radius than carrier-based aircraft.
 * The aerial battle phases of Land-Base Aerial Support are calculated separately from Opening Airstrike and Support Airstrike expeditions, and aerial conditions from one phase will not be carried over to subsequent phases.
 * Plane squadrons will become demoralized (indicated by orange/red face icons) if sortied too frequently.  Accuracy of low morale squadrons is lower compared to normal.
 * When you change an aircraft that is assigned in the land base, the aircraft that is switched out will be tagged with "配置転換中" to indicate that it is currently being relocated, and it will be unavailable to be reassigned to either a land-base or shipgirls for the duration (12 minutes starting from 2016 Summer Event ), do NOT change your aircraft too often.
 * Each airbase slot only has a relatively low number of planes and which is quite susceptible to enemy AA, especially when ships like Light Cruiser Tsu-class are present.
 * Warning: Swapping an aircraft assigned to the land base will cost you Bauxite depending on which plane you are swapping them into. There is no usage indicator to show the potential loss of Bauxite. Do NOT change your aircraft too often.
 * Warning: When a land base squadron is sortied, it will cost fuel and some ammo per squad. Again, there is no indicator that this is happening.

Enemy Raid
In some maps, enemy land bases may assault allied bases with their aircraft. This is triggered semi-randomly, accompanied by a siren sound effect, within the map itself. A certain number of raids (dependant on the map) is guaranteed before reaching the boss.

Damage to the bases can result in losses of planes (starting from the first slot of the base) and resources. Planes cannot be depleted below 1 by raid damage. It has been demonstrated that bombing damage is unaffected by the damage state of the associated base.

To mitigate the effects of enemy raids, players may assign bases to Air Defense in the air base menu prior to sortie.

After an enemy raid, messages will be displayed depending on the amount of damage sustained (see right). The messages are:
 * 空襲により備蓄資源に損害を受けました！
 * Your resources have sustained losses due to the air-raid!

基地航空隊にも地上撃破の損害が発生しました！'''
 * '''空襲により備蓄資源に損害を受け、
 * Your resources, as well as your land-based air fleets, have sustained losses due to the air-raid!


 * 空襲により基地航空隊に地上撃破の損害が発生しました！
 * Your land-based air fleets have sustained losses due to the air-raid!


 * 空襲による基地の損害はありません.
 * The air-raid has inflicted no damage to the land base.

Mechanics
Outlined below is how the LBAS operates during a sortie

All information in this section are now under verification, please treat information in this section carefully.

Fighter Power Calculations

 * Fighter Power Formula from Spring 2016 Event for sortie mode:
 * $$F_{\text{Power}} = \sum^\text{All Slots} \left \lfloor \sqrt{N} \cdot \left ( E_{\text{AA}} + 1.5 \cdot E_{\text{Intercept}} + E_{\bigstar} \right ) + P \right \rfloor$$
 * Where:
 * $$F_{\text{Power}}$$ is the total Fighter Power of the land base.
 * $$N$$ is the current plane count (slot size) of that slot.
 * $$E_{\text{AA}}$$ is the plane's displayed AA stat.
 * $$E_{\text{Intercept}}$$ is the plane's Interception stat.
 * $$E_{\bigstar}$$ is the plane's improvement bonus to the AA stat.
 * $$P$$ is the plane's Aircraft Proficiency bonus.
 * Bonus for Interceptor Fighter = Carrier-Based Fighter, Land-based Attack Aircraft = Carrier-Based Bombers


 * Fighter Power Formula for air defense mode proposed in August 2016 on wikiwiki LBAS page for the system:
 * $$F_{\text{Power}} = \left \lfloor \sum^\text{All Slots} \left \lfloor \sqrt{N} \cdot \left ( E_{\text{AA}} + E_{\text{Intercept}} + 2 \cdot E_{\text{AB}} + E_{\bigstar} \right ) + P \right \rfloor \cdot R \right \rfloor$$
 * Where:
 * $$E_{\text{AB}}$$ is the plane's displayed Anti-Bomber stat.
 * $$R$$ is a bonus given if Recon plane(s) exist in the same land base. Carrier-based Recons seem to give a larger bonus. According to current findings, the value of R is dependent on the Recon plane's LoS stat:
 * For Reconnaissance Seaplanes:
 * 7 LoS or below: $$R = 1.1$$
 * 8 LoS: $$R = 1.13$$
 * 9 LoS or above: $$R = 1.16$$
 * For Carrier-based Recon Aircraft:
 * 7 LoS or below: $$R = 1.2$$
 * 9 LoS or above: $$R = 1.3$$


 * Fighter Power Calculation from each individual squadron/fleet are treated separately in their respective round.
 * Factors like improvement are also taken into account.
 * In Enemy Air Raid, AA stat from enemy recon planes are added into the Abyssal air power calculation.

Sortie Aerial Combat
When you sortie to a designated node the bombing phase is similar to that of the normal Aerial Combat Opening Airstrike stage with a few exceptions:
 * Each squadron will go through the entire process of from stage 1 to 3 once but without enemy bombing, costing losses to enemy fighter group
 * This reduces the fighter power required for the main fleet to obtain air superiority in that node.
 * Yellow or orange text will be displayed at the bottom of the screen if allied plane losses exceed certain thresholds in each attack.
 * The yellow text ( 基地航空隊、未帰還多数) states that your currently attacking squadron has sustained significant damage.
 * The orange text (基地航空隊、被害甚大) is a more severe version of the yellow message.
 * There is no visual display of the air control state (AP/AS/AS+/etc.)
 * The air control state is recalculated for every bombing pass, based on the remaining enemy fighters that survived previous bombing passes.
 * Squadrons can be sent to fleet air raid nodes (single arrow nodes).
 * While bombers will attack enemy airfields, it seems to serve no purpose.
 * Fighter-heavy squadrons can help reduce enemy bombers and decrease damage taken at these nodes.
 * In the case of a concentrated (2x) attack on a single node only, enemy AA defense will eliminate planes during both passes, but only plane losses from the second pass will be accounted for when returning to base. However, it appears plane ranks are lost in accordance with losses from each pass.
 * Therefore, it's possible to have planes left in a slot after a sortie, but still lose all ranks on it.
 * In addition, the bombing damage on the second pass will be calculated ignoring any planes lost during the first pass.

Enemy Raid

 * Squadrons stationed at bases set to Air Defense will protect all land bases from enemy air raids.
 * Intercept and Anti-bomber stats are far more important than Anti-air stat.  See the above fighter power calculation section for details.
 * In addition, these two stats increase the number of enemy planes shot down.
 * Damage to bases can result in semi-random losses of "reserve supplies," which are better known as the player's bauxite and fuel.
 * Resource lost from air raid follow the formula 0.9×(total base hp lost)+0.1 round off to 1 decimal place, and random between bauxite and fuel.
 * If a single base takes 50 or more damage in a single enemy raid, 1~4 planes starting from the first slot will be lost for that base.
 * For example, taking 30 damage to Base 1 in the first enemy raid and 40 damage to Base 1 in the second enemy raid during the same sortie will not lead to losses of planes.
 * Bases set to "Retreat" will not suffer losses of planes in the event of taking 50+ damage, but can still incur resource losses.
 * As aircraft loss starts from the first slot, it is recommended to put fighters instead of other aircraft onto the first slot if fighters are used to minimize bomber or recon plane losses.
 * The damage "tags" on abyssal installation types will be applied to your air bases when they're sustaining damage. For more information you can refer to this page on the types of damage "tags" that are applicable.

Damage Calculation
Note that in this section, CL0 = non-critical hit while CL1 = critical hit, which is different from other pages on the wikia.

The Basic Attack Power of the airstrike is calculated as follows:

For Land-Based Attack Aircraft:

$$\text{Airstrike Dmg} = \bigg \lfloor \left \lfloor \left ( P \sqrt{1.8 N} + 25 \right ) \cdot 0.8 \right \rfloor C_{m} \bigg \rfloor 1.8T $$

For other Bombers:

$$\text{Airstrike Dmg} = \bigg \lfloor \left \lfloor P \sqrt{1.8 N} + 25 \right \rfloor C_{v} \bigg \rfloor T $$

Where:
 * $$P$$ is the bomber's Torpedo or Dive Bombing statistic
 * $$N$$ is the current plane count (slot size) of the slot
 * $$C_{m}$$ is the standard Critical modifier. Assumes a value of 1.5 when CL1 occurs, 1.0 otherwise.
 * $$C_{v}$$ is the Critical modifier affected by Aircraft Proficiency.
 * $$T$$ is the Contact multiplier. Assumes a value of 1.0 if Contact fails.

Additional notes and observations:
 * It has been observed that non-critical damage range (CL0) is different from the regular damage range, or bonus exists.
 * When Ryuusei Kai or Type 1 Land Attack Aircraft attack enemy ships, torpedo animation is displayed but the damage is close to the usual Dive Bomber range, except when CL1 (critical) happen.
 * Dive Bomber and Torpedo Bomber follow same calculation, and their damage difference is only determined by individual plane's stats and plane count. After May 5 fix, Type 1 Land Base Attack. Aircraft's damage have been increased and other things are unchanged.
 * Attack power affected by number of planes remaining in the attacking slot.
 * Number of proficient plane in the squadron does not affect CL0.
 * Placement of Bombers/Attackers does not affect CL0, and probably not for CL1 either.
 * Damage is neither affected by engagement form nor formation.
 * Aircraft Proficiency does not affect Cl0.
 * Whether you focus your attack onto one node or separate them to different nodes, their attack power won't be affected. (It would only affect the number of time you can get LBAS support in that node.)
 * Abyssal flagship protection can happen when attacking abyssals.
 * Contact bonus exists and can be found via API, but there is no graphic display.
 * Bomber damage is not affected by the HP state of the associated base.

Distance Calculations

 * As of the Summer 2016 Event, the range of an entire base is determined by the planes with shortest range stationed within.
 * Stationing long-range scouts will increase the range of the entire base.
 * Range Increase = √([longest range scout in base] - [shortest range in base]), rounded off to 1 decimal place. The max range increase is +3.
 * Range increase effects of various scout planes are as follow :

Morale

 * Orange and red faces (analogous to shipgirl morale indicators) can be seen on individual plane squadrons after repeated sorties.
 * Impacts on performance are not well-tested yet, but it is safe to assume squadrons will exhibit lower performance when fatigued.
 * Squadron morale ranges from 0 to 46.
 * 30-46: normal (no mark)
 * 20-29: fatigued ( orange face mark)
 * 0-19: heavily fatigued ( red face mark)
 * Squadrons default to 40 morale when added to a base.
 * One sortie decreases morale by 6. The decrease occurs after battle.
 * Morale recovers once per 3 minutes. The amount depends on the orders  given  to the base:
 * 【出撃】 Sortie : 1 per 3 min.
 * 【防空】 Air Defense : 2 per 3 min.
 * 【退避】 Retreat: 3 per 3 min.
 * 【休息】 Rest : 8 per 3 min.
 * 【待機】 Standby: 4 per 3 min.

Air Base Location

 * Spring 2016 Event:
 * E-4, E-6 and E-7: Johnston Island Air Force Base at Johnston Atoll (also known as Kalama Atoll), near Hawaii (Abandoned since 2005).
 * E-5: Buin (code name: RXP; abandoned since 1945) and/or Ballale (code name: RXZ; now Balalae Airport) airfield(s) located in Bougainville, Papua New Guinea and Ballale island, Solomon Islands respectively, near Rabaul and Guadalcanal.
 * Summer 2016 Event:
 * E-2, E-3, and E-4: Saigon Airfield, French Indochina (now known as Tan Son Nhut Air Base near Ho Chi Minh, Vietnam).


 * Map 6-5: Kwajalein Atoll, Republic of the Marshall Islands.


 * Fall 2016 Event:
 * E-2: Haneda Air Base near Oota, Tokyo, Japan (now known as Tokyo International Airport, commonly known as Haneda Airport).
 * E-5: Kwajalein Atoll, Republic of the Marshall Islands.
 * Winter 2017 Event:
 * E-1: Kagoshima Air Base near Kirishima, Kagoshima, Japan (now known as Kagoshima Airport).
 * E-2: Tateyama Air Base near Tateyama, Chiba, Japan (founded by the Imperial Japanese Navy Air Service and currently runned by the Japan Maritime Self-Defense Force).
 * E-3: Truk Lagoon, Federated States of Micronesia.
 * Spring 2017 Event:
 * E-2: Chitose Air Base, near Chitose, Hokkaido, Japan.
 * E-3: Mihoro Air Base (now Memanbetsu Airport) near Oozora, Hokkaido, Japan
 * E-4: Kashiwabara Airfield (Imperial Japanese Army airfield), Paramushir, Kuril Islands, Russia (Paramushiru-tou, Chishima Archipielago).
 * E-5: Miyoshino Airfield (Joint Imperial Japanese Army-Navy airfield, currently abandoned) at Shumshu, Kuril Islands, Russia (Shumushu-tou, Chishima Archipielago).
 * Summer 2017 Event:
 * E-4: Royal Air Force Base Salalah (now Salalah International Airport), Salalah, Oman.
 * E-5: Royal Air Force Station Nicosia, Lefkosia, Cyprus.
 * E-6: Tatoi Air Base, Tatoi, Decelea, Greece (Τατόι, Δεκέλεια, Ελλάδα).
 * E-7: Morón Air Base (Base Aérea Morón), originally named Vázquez Sagastizábal Military Aerodrome (Aeródromo militar Vázquez Sagastizabal); Seville, Spain (Sevilla, España).

Trivia

 * When the system was first implemented on May 3rd, 2016, there was a bug that caused the bombing damage from land-base aerial support to be omitted from internal enemy HP damage calculation, which occasionally causes a supposedly sunk enemy unit to be able to act as if they were alive (able to attack/be targeted by your fleet), as shown here
 * Two days after the system's implementation, an emergency update was deployed to fix the performance of land-base attack aircraft.
 * The air base featured in the Spring 2016 Event is the Johnston Island Air Force Base (abandoned since 2005) located at Johnston Atoll, while the air base(s) in Spring 2016 Event E-5 are Buin (RXP; abandoned since 1945) and/or Ballale (RXZ; now Balalae Airport) airfield(s) located in Bougainville, Papua New Guinea and Ballale island, Solomon Islands respectively, near Rabaul and Guadalcanal.
 * In-game, the island allied bases are located on is named Erehwyna Island, an anagram of Anywhere Island. This is likely a tongue-in-cheek reference to the fact that range calculations are based off fleet starting points, which can vary even in the maps themselves, implying the island has the magical property of being able to move to wherever the player fleet starts in each map.
 * After departing Rabaul, Admiral Yamamoto was scheduled to arrival at Ballale Airfield on April 18, 1943 at 11:35 am. His visit was an inspection of the forward airfields and to boost morale, after the loss of the Guadalcanal campaign. Instead, his Type 1 Land-based Attack Aircraft 2656 was shot down over Bougainville.
 * In Spring 2016 Event, refreshing the game before battle result screen appear can avoid losing aircraft proficiency.
 * From Summer 2016 Event onwards, the bases are indicated by a cross marker on the event map.
 * The air base indicator on each map are located in the same location throughout the Summer 2016 Event.
 * The system was revamped for the Summer 2016 Event after its implementation in the previous event, limiting the air fleet's range to the aircraft with the lowest range.
 * If Detection fails, LBAS will continue to attack despite being no enemies on the screen. Enemies would be damaged accordingly.
 * Under some specific, unknown condition, plane lost from LBAS attack (not air defense) are neglected.