U.S. Marine Corps attack helicopters set for major upgrade

The U.S. Marine Corps' H-1 program office is using flight test data from the first two upgraded AH-1Z Viper and UH-1Y Venom helicopters to lock down the SPINE configuration, with modification of the first fleet aircraft set to begin in fiscal 2027. Naval Air Systems Command's Light/Attack Helicopter Program Office, PMA-276, said test points flown so far are feeding into the final aircraft configuration and the technical drawing package for Phase 3.0, the stage that moves the upgrade from test aircraft to operational helicopters. SPINE, short for Structural and Power Improvements for NextGen Effects, strengthens the airframes to carry heavier loads and adds electrical generating capacity so the helicopters can take on new weapons and mission systems. The Marine Corps lists SPINE among its H-1 lethality priorities in its 2026 Aviation Plan. The program office did not say how many test points remain, when the configuration will be frozen or how much additional power the upgrade provides. Developmental testing continues at Naval Air Station Patuxent River, Maryland, with Air Test and Evaluation Squadron 21, Bell Textron and PMA-276 working as an integrated test team. Bell finished the two test aircraft, one AH-1Z and one UH-1Y, in March 2026 after 19 months of structural and electrical work at its Amarillo Assembly Center in Texas. The effort was known as the Structural Improvement and Electrical Power Upgrade, or SIEPU, until early 2026. PMA-276 and Bell are now preparing the Amarillo plant to take in operational helicopters. The work includes buying parts, setting up manufacturing and production lines, readying support equipment and specialized tooling, planning how aircraft will be moved to and from Texas, and aligning SPINE with other H-1 modifications so the work can be done in the same visits. The two organizations are also choosing which aircraft go first and scheduling inductions to keep squadrons supplied with helicopters and to keep the fleet's configuration consistent. "H-1 modernization is critical to maintaining a capable and ready force for aviation-delivered fires in support of Marine Air-Ground Task Force crisis response," said Lt. Col. Benjamin Carlton, capabilities and combat relevance pillar lead for PMA-276. "SPINE will provide greater flexibility for utility mission kits and a digital weapons bus capable of integrating advanced lethality systems, including AIM-9X and other digital weapons." The contracts for that first batch are already in place. In July, the U.S. Navy awarded Bell $33.6 million for SPINE Phase III hardware, including A-kits, D-kits, power generation components and drivetrain assemblies. Bell described the award as a base contract with three option years covering up to 49 aircraft, 28 AH-1Zs and 21 UH-1Ys, with work in Amarillo starting in mid-2027 and first deliveries in 2028. In October, the U.S. Navy exercised a $114.7 million option for 15 A-kits, four mission kits and nine aircraft installations, all due by June 2028. Fiscal 2027 began on Oct. 1, 2026, and runs through September 2027, so the first inductions would fall inside the window Bell gave for the start of work in Amarillo. A digital weapons bus is a data connection between the aircraft's mission computers and its stores stations. It lets the helicopter exchange data with smart weapons before launch, which analog connections cannot do, and new weapons can be added largely through software. That matters for a fleet that is no longer being built: U.S. production of the UH-1Y ended in 2020 and of the AH-1Z in 2022, and the Marine Corps operates about 189 Vipers and 160 Venoms. The two types share about 85% of their components, so one set of SPINE changes covers both. The Marine Corps is already testing missions that will draw on that capacity. On May 13, during an exercise at Twentynine Palms, California, Marine Light Attack Helicopter Squadron 169 used UH-1Ys as airborne control nodes for Neros Archer first-person-view drones, launching one from a helicopter in flight and taking over another launched from the ground. "Government and Bell SPINE teams are continuing developmental testing while preparing for Phase 3.0 modifications in FY27," Carlton added. "The team has prioritized critical test points before the first installations and maintained close coordination throughout engineering reviews. By addressing critical test requirements early and incorporating refinements as the program progresses, the team is delivering enhanced capability to the fleet sooner." Bell and PMA-276 are also working to keep a common technical baseline for the upgraded aircraft, combining Bell's role as original equipment manufacturer with PMA-276's program management, so the modified airframes and mission systems can be supported for the rest of their service lives.