AAM-4B

Also known as

Type 99 Air-to-Air Missile (B)
Type 99 AAM (B)

The AAM-4B is Japan's domestically built medium-range air-to-air missile for F-2 and F-15 fighters. Ministry of Defense budget papers keep funding it as fighter ammunition, and CSIS notes the missile was the first air-to-air design with an AESA seeker.

AAM-4B, Medium-range air-to-air missile, Munitions

Image source: File:JASDF AAM-4B 20131124.JPG

Profile / Specs

Profile

Origin: Japan
Built by: Mitsubishi Electric
Type: Medium-range air-to-air missile
Unit cost: Not publicly reported; Japanese budget documents list procurement totals instead of a public per-missile price.

Specifications

Role: Medium-range air-to-air missile
Platform: F-2 and F-15 fighters
Seeker: Active electronically scanned array (AESA) radar seeker
Length: About 3.7 m
Diameter: About 20 cm
Weight: About 220 kg
Procurement note: Japanese defense budget material keeps listing AAM-4B procurement lines for F-2 and F-15 aircraft

Carrier Aircraft

Official Japanese budget material identifies the fighters that carry this missile.

Carrier	Carrier type	Carriage evidence
F-2 Support Fighter	Fighter aircraft	Japan's Ministry of Defense lists AAM-4B procurement for F-2 aircraft, and CSIS notes the missile was already in service with the F-2 fleet. Sources: Defense Programs and Budget of Japan 2023, Progress and Budget in Fundamental Reinforcement of Defense Capabilities 2024, CSIS Missile Threat: Japan Mulls Equipping F-15J with Domestically-Produced Air-to-Air Missile
F-15 family fighter aircraft	Fighter aircraft	The Ministry of Defense continues to fund AAM-4B for F-15 aircraft, and CSIS reported a July 2019 request to integrate the missile on the F-15J fleet. Sources: Defense Programs and Budget of Japan 2023, Progress and Budget in Fundamental Reinforcement of Defense Capabilities 2024, CSIS Missile Threat: Japan Mulls Equipping F-15J with Domestically-Produced Air-to-Air Missile

Carrier

Carrier type

Carriage evidence

F-2 Support Fighter

Fighter aircraft

Japan's Ministry of Defense lists AAM-4B procurement for F-2 aircraft, and CSIS notes the missile was already in service with the F-2 fleet.

Sources: Defense Programs and Budget of Japan 2023, Progress and Budget in Fundamental Reinforcement of Defense Capabilities 2024, CSIS Missile Threat: Japan Mulls Equipping F-15J with Domestically-Produced Air-to-Air Missile

F-15 family fighter aircraft

Fighter aircraft

The Ministry of Defense continues to fund AAM-4B for F-15 aircraft, and CSIS reported a July 2019 request to integrate the missile on the F-15J fleet.

Timeline

AAM-4B Key Events

Oct 3, 2014
FY2015 request puts AAM-4B into bulk procurement
The Ministry of Defense budget request lists AAM-4B as aircraft ammunition purchased in bulk over three years, showing the missile entering a recurring procurement pipeline.
Sources: FY2015 Budget Request
Jul 17, 2019
MOD seeks F-15J integration
CSIS reported that Japan's Ministry of Defense issued a request for proposals to integrate AAM-4B on the F-15J fleet, extending the missile beyond the F-2.
Sources: CSIS Missile Threat: Japan Mulls Equipping F-15J with Domestically-Produced Air-to-Air Missile
Jun 7, 2024
FY2024 budget keeps AAM-4B funded
The FY2024 defense buildup budget continues AAM-4B procurement at JPY 16.3 billion for F-2 and F-15 aircraft.
Sources: Progress and Budget in Fundamental Reinforcement of Defense Capabilities 2024

Procurement Context

These are budget lines rather than public per-missile unit prices. They show how AAM-4B procurement has remained a recurring fighter armament item.

Budget year	Amount	What the line says	Source
FY2015 request	JPY 19.0 billion	Bulk purchase of aircraft ammunition for three years, with expected savings of JPY 2.6 billion.	FY2015 Budget Request
FY2023 budget	JPY 11.9 billion	AAM-4B procurement for F-2 and F-15 aircraft.	Defense Programs and Budget of Japan 2023
FY2024 budget	JPY 16.3 billion	AAM-4B procurement for F-2 and F-15 aircraft.	Progress and Budget in Fundamental Reinforcement of Defense Capabilities 2024