Bell Textron, a subsidiary of Textron, has completed the first AH-1Z and UH-1Y helicopters fully upgraded under the US Marine Corps’ (USMC) Structural and Power Improvements for NextGen Effects (SPINE) programme.

According to an announcement on 17 March 2025, the aircraft have left the Amarillo Assembly Centre and are now undergoing further flight tests at Naval Air Station Patuxent River.

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The evaluation phase will determine the final configuration of the SPINE modifications, which will be implemented at Amarillo before being introduced to the broader US Marine Corps H-1 fleet in subsequent contracts.

Previously known as the Structural Improvement and Electrical Power Upgrade (SIEPU), the programme was renamed SPINE to reflect its focus on future operational requirements for the H-1 platform.

The SPINE modifications are designed to allow the H-1 fleet to accommodate advanced weapons systems and new capabilities. This initiative forms part of broader efforts to modernise the H-1 programme by improving operational effectiveness and survivability.

Bell H-1 programme director Scott Sims said: “To have these first two aircraft completed under the SPINE program is a huge moment for us. At Bell, crew safety and aircraft effectiveness remain the number one priority on everything we do.

“These upgrades will ensure that our H-1 aircraft remain the most capable aircraft available, while operating at the forefront of modern missions. They will continue to excel at the job they were designed to do for many years to come.”

Modification work on these initial helicopters began at Bell’s Drive System Centre (DSC) and Repair and Overhaul Centre (ROC), with electrical and structural changes taking place over a 19-month period at Amarillo.

Years of collaboration between Bell, industry partners, and the US government contributed to successful delivery of this upgrade effort.

With these first modifications complete at Amarillo Assembly Centre, Bell plans to continue upgrading additional USMC H-1 helicopters over the next decade.