Sidewinder

The LI 2209 - Sidewinder program is a Navy budget line item focused on the procurement and sustainment of the AIM-9X Block II Sidewinder missile system. This program supports the acquisition of advanced infrared-guided air-to-air missiles, which are essential for maintaining air superiority and providing first shot, first kill capabilities for fighter aircraft in close combat scenarios. The AIM-9X Block II is designed to operate in environments with sophisticated electronic countermeasures and modern stealth technology, complementing radar-guided missiles such as the AMRAAM. The overarching goal is to ensure the lethality and survivability of U.S. Navy and joint force fighter aircraft against evolving aerial threats.

The AIM-9X Block II procurement objective is to acquire the 12th lot of Full Rate Production (FRP) AIM-9X Block II missiles in FY 2026, with a planned procurement for the Navy. The program is managed as a joint service effort led by the Department of the Navy, with participation from the Air Force, Army, and Foreign Military Sales (FMS) customers. The total approved Acquisition Program Baseline (APB) quantity includes missiles for both the Navy and the Air Force. The procurement strategy is designed to maximize missile quantities within available funding, in accordance with Title 10, US Code Section 2308, Buy-to-Budget Acquisition, due to inventories being below the Navy's Total Munitions Requirement.

The All Up Round (AUR) and Captive Air Training Missile (CATM) lines represent the two primary configurations procured under this line item. AURs are operational missiles, while CATMs are used for training purposes. The majority of missile components are common between these configurations, and unit costs are heavily influenced by total program quantities across all customers. Procurement quantities in recent years were increased by supplemental appropriations, notably to replace Navy stocks expended in support of Ukraine, with additional funding provided by the Ukraine Security Supplemental Appropriations Act, 2024. This resulted in significant increases in missile and container quantities for those years.

The Inertial Measurement Unit (IMU) Obsolescence Upgrade is a reliability-focused modification effort within the Sidewinder program. The goal is to replace the obsolete AIM-9X-2 Guidance Unit (GU), which accounts for the majority of missile failures, with the upgraded AIM-9X-4 GU featuring a Ring Laser Gyro. This upgrade is expected to increase operational availability and reduce repair turnaround time. The budget includes procurement of upgraded GUs, with installation occurring during missile repair at no additional cost.

The Production Technical Support and Ancillary Equipment lines provide funding for technical documentation, training development and delivery, cyber security, and management of government-owned property to support missile production. Cyber security requirements have become increasingly important, with funding allocated to protect controlled unclassified information (CUI) and higher classifications exchanged during production. Additional support costs cover calibration and procurement of support equipment, technical publications, training manuals, telemetry kits for live-fire exercises, and program office support.

The Engineering Change Orders (ECO) and Diminishing Manufacturing Sources (DMS) lines address ongoing production challenges. ECO funding is used to test and qualify engineering changes into missile production, calculated as a percentage of AUR and CATM quantities. DMS funding supports life-of-type buys and the design, development, and qualification of replacement components due to changes in sub-vendor manufacturers, ensuring continued missile production and reliability.