The United States Navy has awarded Pratt & Whitney a contract valued at up to $1.6 billion to sustain the F135 propulsion system that powers all variants of the F-35 Lightning II, the world’s largest and most widely deployed fifth-generation fighter program. The agreement ensures continued global support for the rapidly expanding fleet operated by the United States and its international partners.
According to the Pentagon’s announcement, the undefinitized contract — capped at $1,606,190,091 — covers an extensive range of services running through November 2026. The funding includes cost, cost-plus-fixed-fee, cost-plus-incentive-fee, and fixed-price-incentive-fee components, reflecting the diverse technical and logistical requirements involved in sustaining one of the most complex military engines ever fielded.
Pratt & Whitney, a subsidiary of RTX, will provide comprehensive support for the F135 engine at both the unit and depot levels. The sustainment package includes global maintenance services, replenishment spare parts, software updates, engineering support, supply chain and material management, configuration and product management, propulsion integration, and security management. It also covers Joint Technical Data updates, support equipment management, and depot-level repair activities for all fielded propulsion systems across F-35 production plants and operational bases worldwide.
The Pentagon noted that the contract’s scope ensures “recurring sustainment support, program management, financial and administrative activities,” along with full-spectrum maintenance and logistics assistance crucial for a fleet with increasing sortie rates and expanding operational commitments. A total of $98,975,737 in obligated funds will expire at the end of the current fiscal year, underscoring the urgency attached to maintain uninterrupted support pipelines.
The F135 engine is the central propulsion system for the F-35A conventional takeoff variant, the F-35B short takeoff/vertical landing (STOVL) model, and the F-35C carrier-based variant. Operated by the U.S. Air Force, Navy, and Marine Corps, the engine also powers the jets flown by partner nations such as the United Kingdom, Italy, Japan, Australia, Norway, the Netherlands, and others participating in the Joint Strike Fighter program.
As of 2025, more than 1,000 F-35 aircraft have been delivered globally, with production and deployment accelerating across Europe and the Indo-Pacific. This growth has intensified demand for sustainment, supply chain resilience, and depot-level capacity, especially as more nations transition from initial operational capability to full operational use.
The F135 is widely regarded as one of the most technologically advanced and maintenance-intensive engines in U.S. military aviation. The F-35B’s unique STOVL lift-fan configuration and the F-35C’s higher-stress carrier operations add further complexity to sustainment demands. The engine’s performance requirements — including extreme thermal loads and high sortie rates — have led to recurring debates within the Pentagon over long-term modernization, upgrade pathways, and funding strategies.
Despite these challenges, the Pentagon continues to prioritize F135 sustainment to ensure fleet readiness and mission availability as the aircraft assumes a growing share of U.S. and allied airpower missions. The latest contract reflects ongoing efforts to stabilize the global support ecosystem and ensure a reliable flow of parts, maintenance, and technical updates.
Work under the contract is expected to be completed by November 2026, with services and repairs taking place across U.S. facilities and international F-35 operating locations.
As geopolitical tensions grow and allied air forces deepen their reliance on fifth-generation platforms, maintaining the F135 propulsion system has become critical to ensuring that the F-35 remains fully combat-ready. The new sustainment contract marks another major investment in the long-term, reliability, and global interoperability of the F-35 fleet.
