Pratt & Whitney's F135 Enhanced Engine Packages (EEP) are the only cost-effective, capable, and proven variant-common solution that can enable full Block 4 capability for the warfighter and reduce billions in sustainment costs for the taxpayer.


Growth in aircraft capability must be matched with propulsion modernization to ensure the full mission capability of the F-35 weapon system, now and in the future.

Designed with the knowledge that operational environments evolve and threats advance, the F135’s modular design and advanced digital architecture allow for spiral development and insertion of both hardware and software.


Pratt & Whitney developed EEP for the F135 with the objective of providing the most cost-effective solution to meet future F-35 propulsion requirements. This means inserting the latest technologies into the F135 without breaking variant commonality, which would drive increased costs into the program.


As the air vehicle grows, so must the engine. To date, there is no propulsion growth requirement or funding commensurate to support planned Block 4 air vehicle upgrades. This needs to urgently change as planned air vehicle growth will soon exceed the current F135’s capabilities.


Without propulsion modernization, there will be substantial operational impacts for F-35 warfighters and sustainment cost increases for the taxpayer.


EEP is the only cost-effective, variant-common modernization solution for the F-35 that can fill this capability gap AND reduce sustainment costs. 

With room for growth for tomorrow’s missions, the F135 is uniquely postured to meet the evolving demands of the F-35.

F135 EEP: Joint Solution for the JOINT STRIKE FIGHTER

  • Cost-effective

    EEP is the only solution that enables full Block 4 capability without driving billions of dollars into program costs and bifurcating the F-35 fleet. In accordance with program design, EEP is a variant common modernization solution that leverages the existing production and sustainment infrastructure and maximizes cost share across all Services and Partner countries. EEP is production cost-neutral and will generate billions in sustainment cost savings over the life of the program.

  • Next-gen capability

    EEP leverages $2 billion of U.S. Government adaptive engine investment to provide next-generation capability to the F-35 at an affordable cost –  all within the confines of the existing program construct. EEP can provide double-digit improvements in range, thrust and thermal capacity and will meet the F-35 propulsion requirements necessary to fully enable Block 4 capabilities for the warfighter. Additionally, EEP can be optimized to further increase a specific propulsion performance parameter, such as fuel efficiency, should the customer desire.

  • Low-risk
    EEP is low-risk, leveraging proven technologies that have been matured for years under various advanced engine programs, and doesn’t disrupt the program of record. EEP was designed from the onset to be seamlessly integrated into production and/or retrofit during engine overhaul.


More about the F135