Vertibird (Fallout 4)

Characteristics
The Vertibirds utilized on the East Coast have transparent cockpits, sliding doors on the cabin, a minigun on the lefthand side, and folding wings and rotors. The Vertibird also has a docking hook along the top near the tail, that links with the docking hook/arm on the flight deck of the Prydwen. Different from previous models is the model's retractable landing gear, in a different configuration with one along the centerline at the front of the aircraft and the other three in a tricycle layout at the rear of the fuselage.

There is one known model used by the pre-War United States Armed Forces and Arthur Maxson's Brotherhood of Steel, a bulkier transport model with a glass cockpit, retractable side doors, collapsible wings, and two additional jet engines behind the main cabin.

The Vertibird's VTOL flight mechanics allow it to approach landing zones, transiting into a hovering mode of flight, by tilting its rotors vertically upwards 90 degrees. Vertibirds lack the large armament package seen in the Capital Wasteland. When dropping the Sole Survivor off in an area inhabited with hostiles, the Vertibird will sometimes support them by firing on the hostiles with its machine guns.

Vertibirds are easily destroyed by ranged weapons and can be targeted in V.A.T.S. When a Vertibird is airborne and takes enough damage, it starts spinning on its Y axis, similar to how helicopters spin when they lose their tail rotor, before crashing into the ground and exploding, similar to a mini nuke explosion. The Vertibird usually breaks up into four large pieces upon crashing, releasing small amounts of radiation for a short while. However, if the Vertibird takes an immense amount of damage, such as a direct hit with a two-shot Fat Man MIRV or an upgraded explosive minigun, the Vertibird will slowly fall to the ground and pass through it. Marking with a recon scope can show its progress under the terrain.

Although the Brotherhood of Steel operate nearly all functional Vertibirds seen in Fallout 4, the Gunners also possess one functional Vertibird, which can be encountered in the southwestern portion of the map. They at one point possessed at least one more, which crashed into the Mass Bay Medical Center. The Minutemen and the Railroad may also come into possession of a single Vertibird. The Good Fighters have also managed to repair two Vertibirds and make them flightworthy.

Locations

 * The first Vertibird appears in the opening sequence of the game, flying over Sanctuary Hills and landing next to the entrance of Vault 111. Another Vertibird hovers over the Old North Bridge.
 * Later, several crashed and wrecked Vertibirds can be found throughout the Commonwealth. Near the wrecked Vertibirds, power armor can commonly be found.
 * The first Vertibird seen in the post-War Commonwealth if following the main story is one crashed on the roof of the Museum of Freedom. Michael Daly's power armor can be recovered there during the quest When Freedom Calls.
 * Operational Vertibirds are seen after the quest Reunions when a Brotherhood of Steel force shows up with the Prydwen. Afterward Brotherhood of Steel Vertibirds are seen flying, sometimes in pairs, throughout the Commonwealth deploying squads or firing on hostiles. After the quest Show No Mercy, the player character gains the ability to call in a Brotherhood of Steel transport Vertibird by using a Vertibird signal grenade. Alternatively it is possible to gain this ability in the end-game when siding with the Railroad (after completing The Nuclear Option) or with the Minutemen (after completing With Our Powers Combined).
 * Crashed Vertibirds are found at around 18 locations in the Commonwealth, including Coast Guard pier, the Glowing Sea, Mass Bay Medical, Boston Airport, the National Guard Training Yard, as well as at various wilderness locations and military checkpoints.

Player Travel

 * To travel by Vertibird: drop a Vertibird signal grenade in a suitable location, wait for the aircraft to land nearby, approach the aircraft until the option to Ride is shown, then select it. Onboard the Vertibird, open the Pip-Boy's Map page and select a location for Fast Travel.
 * Regardless of whether the character approaches the left door or the right door, the boarding animation shows them entering the left door and taking up position on the left door's door gun.
 * The Vertibird will attempt to land as close as possible to the colored smoke signal. However in highly congested terrain, the game may report that it is not possible for a Vertibird to land at the player's location. The signal grenade is still expended.
 * In general, it is not possible to request landings on the roofs of buildings, not even designated helipads.
 * However, in landing to drop off at the destination (not for pickup) the Vertibird will attempt to land as close as possible to the Fast travel target, including if this is placed on a roof or similar surface, provided the surface is large enough and a clear glide path exists.
 * In moderately congested terrain, the Vertibird may need to land some distance away, potentially out of sight. A landed Vertibird will always add a quest to the Miscellaneous section. Initially, this is inactive. If activated, the quest marker can be used to locate the Vertibird. Once activated, this quest marker will automatically be activated for future landings, until it is deliberately deactivated.
 * En route, the player may select Land to land near to the current location rather than the destination that was selected on the map.
 * If over water, the Vertibird will travel to a nearby land area to land.
 * If one selects Land by accident while traveling to a location, re-selecting any location (on the Map page) will result in resuming flight to that location.
 * The Vertibird can be made to change destination mid-flight at any time by selecting a new destination, at any time prior to final descent at the currently selected destination.
 * Traveling by Vertibird is significantly faster than fast-traveling, even when factoring in the time for the aircraft to arrive.
 * Travel by Vertibird can add fast-travel locations and points of interest to the Pip-Boy while in route. It can also update incorrect or outdated settlement workshop data if passing sufficiently close to a settlement.
 * Traveling over radioactive areas is less dangerous than walking through them. The vertical distance from the surface of the ground (or other radiation source) reduces the radiation effect, meaning that for example, in the Glowing Sea radiation effects will be experienced only while crossing very high places (such as the ridges of the Crater of Atom) or during take-off/landing ascent/descent.

Player Combat

 * The door-mounted minigun when used by the player has a base damage (DMG) of 25. This damage is increased by the Heavy Gunner and Lone Wanderer perks, amongst others.
 * There is also a hidden perk that adds 5 DMG to all Vertibird-mounted weapons, including miniguns (player and NPC). This is applied additively, not multiplicatively, after any other perks.
 * As with the DMG, the minigun's other stats are not normally visible to the player, but they are: ROF 272, Range 514, Accuracy 43.
 * Compared to the minigun on NPC Vertibirds, the player minigun is also superior in range, suffering no range penalty out to 1000 range.
 * The Vertibird miniguns use special 5mm ammo (similar to companion special ammo) which can't be obtained or retained by the player. The player minigun is equipped with 1000 rounds of this ammo. However in a normal game this ammo can never be consumed.
 * The minigun may be fired when the aircraft is on the ground (after boarding and before take off, but not after landing) as well as while airborne.
 * By selecting a sequence of destinations in a crude counter-clockwise circle or polygon around a target, it is possible to "orbit" that target indefinitely, for example to fire on the target with the door gun.
 * During travel, the player character cannot use VATS, grenades or any weapon other than the door gun. The player character can access the Pip-Boy screens and use inventory-equip shortcuts.
 * The aim point crosshair for the minigun is very wide when hip-firing (indicating a wide spread), and disappears when aiming in first person view. In third person view, there is no aimpoint dot. It is only possible to aim down the door gun's barrel "by eye" in first person view.
 * In Survival mode, periodic damage from over-encumbrance does not occur while traveling in a Vertibird. Thirst and hunger effects, and periodic damage from disease, occur in the normal way.
 * As noted, there is no limitation on the ammunition capacity of the door gun in a normal game.
 * The door gun cannot do damage to the Vertibird it is mounted in. It can damage (and destroy) other Vertibirds.
 * Locations are still marked as CLEARED even when achieving combat objectives only by using the Vertibird's door gun.
 * Wearing power armor while traveling aboard a Vertibird will still drain the armor's fusion cores. Even though one is not physically moving the armor, the Vertibird travel still counts towards the depletion of the fusion energy.
 * While flying over a raider captured outpost, the turrets and raiders there will attack the Vertibird and its pilot, but will neither be able to hit it nor be hostile against the Sole Survivor.
 * Friendly transport Vertibirds summoned by signal grenades can not be targeted in VATS.

NPC Combat

 * Encountered Vertibirds are leveled in a similar way to monsters and other NPCs. The levels range from 20 to 50. Offensive capability is the same for all variants. Defensive ability varies with level:
 * L20: 60 DR/ER, 910 base HP
 * L30: 90 DR/ER, 1110 base HP
 * L40: 112 DR/ER, 1310 base HP
 * L50: 135 DR/ER, 1510 base HP
 * The most important offensive capability of an encountered Vertibird comes from its occupants, who will use the door minigun and/or personal weapons.
 * The door minigun on an NPC Vertibird has a base damage (DMG) of only 5, increased by a special perk to 10. They have an ammunition capacity of only 500 rounds of the special 5mm ammo, though this will not be a factor in a normal game. They suffer a range penalty that increases to 50% between range 500 and range 1000. The rate of fire and accuracy are the same as the player Vertibird minigun.
 * The built in guns on the fuselage are even more ineffective, as they have a base damage (DMG) of only 1, though the same perk increases this to 6.
 * Brotherhood of Steel pilots and door-gunners on randomly encountered Vertibirds have a perk that reduces explosion damage by 50%.
 * There is a much weaker variant of the Vertibird that appears only in the pre-War prologue (War Never Changes). This variant only has 50 DR, 0 ER and 510 base HP. However, it is not normally possible to interact with this Vertibird.

Behind the scenes
In The Art of Fallout 4, the Fallout 4 Vertibird is described as the "result of a goldfish meeting a Hind helicopter."

Bugs

 * The wreckage from a destroyed Vertibird may continue to move long after it has crashed, sending (harmless) fuselage spinning over and over around the crash-site.
 * Boarding a signaled Vertibird that has landed in Boston Common Pond will cause you to remain irradiated, even after landing.
 * Idling long enough inside the Vertibird to where the camera pans around the character in third person, then moving the camera after landing, may cause the player to become stuck inside, and the Vertibird will take off with the player unable to move. After a few moments, the player will fall out of the Vertibird.
 * When a Vertibird runs out of health, it is supposed to spin wildly out of the air and crash into the ground. However, sometimes a glitch occurs where it gets staggered while this is happening, causing the Vertibird to become 'zombified'. It will hover in the air and slowly drift towards the ground, sometimes even sinking into it rather than exploding like it should.
 * The Vertibird can suffer from Wounding Legendary weapon effect (bleed). With enough sequential hits and using enough powerful weapon, like Pickman's Blade, the Vertibird's life can be seen diminishing from bleeding through V.A.T.S.
 * The Vertibird can suffer from having the minigun disappear after the player has taken off, essentially making it defenseless for the remainder of the journey. there seems to be no set trigger. moving or not moving, panning the camera or not. zoomed in or out.
 * In the event of the minigun disappearing, it is then possible to select other weapons from inventory and - for automatic weapons and melee weapons only - attack with them.
 * The Vertibird and player character can glitch through the Prydwen while maneuvering to dock with the player character on board.
 * The Vertibird and player character can glitch under the ground or under water while maneuvering to land with the player character on board. This is rectified by the time the player character is ready to disembark the aircraft. It seems to be more common at the waters edge, for example outside The Castle or at Nordhagen Beach.
 * While aboard a Vertibird, energy damage (DMG) of personal weapons (excluding mines and throwables, and radiation damage) is reported by the Pip-Boy as 6x times normal. It is unclear whether the weapons would actually do this damage, since they cannot normally be used when aboard a Vertibird.