# AIM-174B

The AIM-174B is a long-range air-to-air missile (AAM) developed by U.S. defense contractor Raytheon and used by the United States Navy (USN). The AIM-174B is a derivative of the RIM-174B Standard Extended Range Active Missile (ERAM, Standard Missile-6, or SM-6) surface-to-air missile, a member of the extended Standard Missile family, with the USN describing the AIM-174B as the "Air-Launched Configuration" of the SM-6. The AIM-174B's existence was first confirmed to the public in July 2024 at RIMPAC 2024. The AIM-174B is only known to be capable of being carried and launched by the Boeing F/A-18E/F Super Hornet as of July 2024.
Since the 2004 retirement of the AIM-54 Phoenix AAM, the USN has not fielded a dedicated long-range air-to-air missile. The AIM-174's existence had been speculated about since at least 2021, with photos of SM-6s carried by Super Hornets making their way online. The publication Naval News reports that they were following developments of an "air-launched SM-6" since 2015, while The Aviationist reports that photos of Super Hornets carrying "an SM-6 variant" appeared in 2018.
Little is known about the missile as it is speculated that it was developed as a special access program, similar to the AIM-260 Joint Advanced Tactical Missile (of which little is officially known). As the AIM-260 is similarly a very long-range air-to-air missile, it is unclear what the relationship between the AIM-174B and AIM-260 will be, as the USN has co-operated with the United States Air Force (USAF) in developing the latter for use by both services. Both missiles are designed to counter the extreme-range air-to-air missiles being fielded or under-development by the United States' peer and near-peer potential adversaries, such as the Russian Vympel R-37M or the Chinese PL-21. Both the AIM-174 and -260 are separate from the currently under-development Long-Range Engagement Weapon of the USAF.

## Design

Photos reveal that the AIM-174B weighs around 1,900 lb (861 kg), about five times the weight of the AIM-120 AMRAAM. These photos also show that the AIM-174 is externally virtually identical to the RIM-174, apart from the marked lack of the MK72 solid-fuel rocket booster on the AIM-174. The missile will likely utilize a solid-fuel rocket engine, as carried by the RIM-174.
In September 2024, photos emerged of a USN Super Hornet of the VX-9 'Vampires' carrying four AIM-174Bs, three AIM-120 AMRAAMs, two AIM-9Xs, and an ATFLIR targeting pod simultaneously.

## Range and use

While details regarding the AIM-174's range are unconfirmed, certain surface-launched SM-6 variants are capable of 250 nmi (290 mi; 460 km) launches; with the benefit of being launched at speed and higher altitude (where the air creates less drag), the AIM-174's range may extend hundreds of miles though the USN has only confirmed a range of 130 nmi (150 mi; 240 km).
While the AIM-174 lacks the SM-6's MK72 rocket booster, in the thinner air of higher-altitudes (relative to a surface launch) and retaining the speed of the launching aircraft (several hundred miles per hour, at minimum), an air-launched AIM-174 may be capable of extreme ranges (300–400+ kilometres), relative to other air-launched missiles. The AIM-174 may also be capable of ‘lofting,’ a technique whereby the launched missile immediately ascends upwards to gain altitudes generally between 80,000 ft (24,000 m) to 100,000 ft (30,000 m). The AIM-174's predecessor, the AIM-54 Phoenix BVRAAM was capable of employing this launch profile (along with certain AIM-7 Sparrow variants and all AIM-120 AMRAAM variants). Between the AIM-174's advantages over a surface-launched SM-6 and the possibility of lofted-launch profiles, the AIM-174's range may extend to hundreds of nautical miles. The USN also routinely understates the publicly-available ranges and capabilities of weapon systems for strategic security purposes. At minimum, the AIM-174 represents a roughly 30% increase in range over the 99 nmi (114 mi; 184 km) of the retired AIM-54C and a roughly 50% increase over the 87 nmi (100 mi; 161 km) of the in-service AIM-120D AMRAAM.
Very long-range AAMs such as the extant R-37M and the nascent PL-21 are typically utilized to attack large airborne targets; their current efficacy in attacking smaller targets (such as air superiority fighters or drones) is unknown. The AIM-174 will likely be subject to similar operational and practical limitations, and will likely be reserved for use against high-value airborne assets. As such, it is speculated that the AIM-174 could be used offensively to strike at tankers or airborne early warning aircraft and electronic warfare aircraft far behind the ‘frontlines’ or defensively to strike large bombers — such as China's Xi'an H-6 — threatening USN fleets.
As the RIM-174/SM-6 is capable of anti-ship and anti-ground strikes, the possibility exists for the AIM-174 to be utilized in such capacities. Derived from the SM-6 family — whose variants are capable of anti-ship missile defense and anti-ballistic missile launches — the AIM-174 will likely retain such anti-missile capabilities.