Why some fighter aircrafts need two pilots?

[Yuri Bezmenov]

This is more a technical question than a gameplay-related one.

I get that there are big planes such as the AC-130 that require various crew members to function properly. But why do fighter aircrafts have two pilots? How does the second pilot contribute to the combat in a fighter aircraft if the main pilot is controlling it?

[Kappatalism]

One person to focus on flying, one person to focus on weaponry.

Here's a copypaste from wikipedia:

A Weapon Systems Officer (WSO; "wizzo" as a common nickname) is an air flight officer directly involved in all air operations and weapon systems of a military aircraft.

Historically, aircrew duties in military aircraft were highly specialised and rigid, because the relevant controls, instruments/displays, and/or weapons were concentrated in front of particular seats, panels or positions. That included two-seat variants of fighter or attack/strike aircraft (including late 20th century types such as the F-4 Phantom II, A-6 Intruder, F-111, Panavia Tornado, Su-24 Fencer and Su-30MK Flanker-C, Dassault Mirage 2000N/2000D).

From the 1970s onward an aircraft with two-member crews, such as the F-15E Strike Eagle, F/A-18F Super Hornet or Su-34 Fullback and Dassault Rafale B have often featured programmable multi-function displays. These programs allow roles to be more flexible than previous generation aircraft. Multiple crew members can be responsible for detecting, targeting and engaging air-to-air or ground targets, communications, datalinks and/or defensive systems. Roles can be customized based on experience, expertise, workload, tactics, and weapons being employed. Pilots usually retain the responsibility for flying the aircraft in tactical situations. However, the crews of dedicated bomber aircraft usually retain distinct, rigidly-defined and conventional roles.

[Atlessa]

https://www.youtube.com/watch?v=_f351_w8jf0

This guy was a RIO (second seat) in an F-14. Highly interesting stuff if you're into that sort of thing.

TL,DR: The RIO operates the Radar, can fire (some?) weapons, acts as a second set of eyes during combat and operates the Radio. Bascially he makes the life of the pilot a lot easier.

[Agent 32]

Some aircraft have different duties despite being within the "fighter" family. Such as the EA-18G which is a variant of the F-18 Super Hornet. The EA-18G is electronic warfare which needs its backseat so one can fly while the others "attacks". Another use case for a backseat is when the F-18 is loaded with 5 drop tanks with the centerline being a specialized drop tank able to fuel other aircraft. While it is a little weird to have a fighter preform act as a tanker it does make sense in terms of the navy cause they don't have KC-130's to give them fuel out at sea or in country where the air force cannot support. It's more of trying to make the carrier group less dependent on other forces. That being said the single seat guys have a lot of pride in the fact that they don't need WSO's since they are being sent on the same missions as the two seats. Also remember even if the whole USA went single seat pilots need to be trained. There is no difference between a training squadron aircraft and a sea going squadron. The aircraft are interchangeable as the best training platform is the one you'll be flying anyways. Might as well make it so it can preform combat rolls just in case.