Before we get into the parts, let’s talk about the plane. It has an enormous job to do. The U.S. military is counting on the F-35 to replace several fighters including the Air Force’s F-16s, the Navy’s and Marine Corps’ F/A-18s, the Marines’ AV-8B Harriers and the UK Harrier GR7s and Sea Harriers. That means it has to excel at air-to-air combat, carry out air-to-ground precision strikes in all weather, fly stealthily into contested areas, have unsurpassed “situational awareness,” or data on what’s going on around it, and land basically wherever the military needs it to land. And it needs to be “survivable,” a military term meaning it can either avoid or withstand attack.

“The Air Force is really buying it to be the workhorse of its fighter community. The Navy is doing the same,” said retired U.S. Air Force Maj. Gen. Jon Norman, who leads Air Power Requirements and Capabilities for Raytheon Missiles & Defense.

The U.S. expects to fly the F-35 well into the 21st century, and other nations have placed their bets on it as well. The armed services of the United Kingdom, Italy, Germany, Netherlands, Australia, Norway, Denmark, Finland, Canada, Israel, Japan, South Korea, Poland and Belgium all fly the fighter or have plans to do so.

The F-35’s engine

The F-35 gets its thrust and the bulk of its electric power from Pratt & Whitney’s F135 engine – an evolution of the F119 engine, which powers the F-22 Raptor.

The F135, known as a fifth-generation engine, has several advantages over the previous generation. It produces more thrust, it can handle heat more efficiently, and has a precise, responsive control system that relieves pilots from having to monitor multiple gauges and inputs simultaneously – and allows them to focus instead on their missions. The F135 is also built from advanced materials and has a modular design that allows for efficient and effective maintenance and upgrades.

The F-35 is still early in its service life, but the U.S. Department of Defense has already begun working on a modernization effort to ensure the fighter jet keeps pace with adversaries. That effort, known as Block 4, includes new weapons, cockpit improvements and other upgrades that would increase the demand on the engine for cooling and power – so much, in fact, that it would push the F135 far beyond its original specifications, resulting in increased sustainment costs. That means a modernized F-35 needs a modernized engine as well.

To that end, Pratt & Whitney is proposing an upgrade to the existing F135 engine called the Enhanced Engine Package, or EEP. The business’ military aviation experts point to several key benefits – mainly cost-effectiveness, low risk and a schedule that would bring Block 4 capabilities to the F-35 years sooner than a completely new engine.

In terms of affordability, Pratt & Whitney estimates EEP would save approximately $40 billion in lifecycle costs, thanks to several factors:

  • It is “variant-common,” an important hallmark of the F-35 program that means it can work on all three versions of the fighter.
  • It would use the existing F135 production and sustainment infrastructure, and it would maintain the current cost-share ratios for the U.S. services and international partners.
  • It is production-cost neutral, meaning an upgraded F135 off the assembly line would cost the same as the current configuration.

As for low risk, EEP builds on an architecture that has already logged more than a million flight hours of safe operation between the F135 and F119. It adds no extra weight to the aircraft and requires no modifications to fit inside, making it what’s known as a “drop-in” upgrade.

And when it comes to the fast delivery schedule, EEP has an advantage because it is a retrofittable upgrade to the existing engine, with a mature supply chain, a production line running at full rate and an established maintenance network. The result would be more upgraded F135s and fully enabled Block 4 F-35 aircraft, sooner.

“With EEP, we’ve incorporated the latest technology to give pilots the capability they need, while still maintaining variant-commonality to maximize affordability,” said Jen Latka, Pratt & Whitney’s vice president for the F135 program. “And in the future, if the customer wants to bring even more capabilities into the jet, they wouldn’t need to do this again. You still have margin and headroom with EEP.”

EEP even has advantages in sustainability. It will reduce carbon dioxide emissions by 43 million tons over the life of the program and, like today’s F135, will be ready to use sustainable aviation fuels.