Pratt & Whitney (P&W) has announced that it has reached a new handshake agreement with the military for a fourth batch of low production rate F135 engines. These engines power the F-35 aircraft in various forms. The fourth batch of engines will reportedly have a price of 16% less than the previous batches. Pratt & Whitney military engines Chief Warren Boley has noted that P&W is working to get the cost per engine down to about $10 million.

He also noted that the previously reported issue with the engines described as "screech" had been solved and that all new engines would have the fix applied on the assembly line and that the engines already in the field could have the fix installed easily in depot. Boley also stated that all three of the engine versions have received the Initial Service Release that certifies development is complete and so far, the engines have shown 99% reliability.

The most problem-prone version of the F-35 that uses these engines has been the F-35B and Boley noted that it had a mission readiness of 98% for the propulsion system. The F-22 uses the F119 engine and it by comparison has a reliability rating of 98.5%.

P&W is still working to improve the reliability of the F135 engine and improvements will be applied to the sixth and seventh production batches of the engine. Changes are minor according to Boley and will be able to be applied in the field to the existing aircraft.

In the military aviation world the more off the shelf parts you can incorporate into a new aircraft design, the cheaper the aircraft will be, the faster it can be fielded, and the more reliable the aircraft is in general. When the Air Force announced that it was lowering expectations for a new long-range bomber, the need for off the shelf parts was noted.

The USAF vision for a new bomber could include the engines used in the F-35 fighters according to Boley. He noted that if the bomber program is not as ambitious as stated by the Air Force the F135 engines could be used in the aircraft and that they would "most definitely" be suitable for a long endurance aircraft.

Boley said, "So the future bomber may be much more off the shelf, much more proven technology, it may be a subsonic bomber, it may use a proven [F-35 Pratt and Whitney] F-135."

Defense News notes that previously officials familiar with long-range strike aircraft had said that the F119 engine from the F-22 and the F135 engine from the F-35 burned fuel too quickly for a long-range aircraft.

P&W is also working on a new engine called the PW9000 that uses the low-pressure compressor from the F135 mated to a core from the geared turbo fan. This engine could possibly be used on the Navy Unmanned Carrier Launch Surveillance and Strike aircraft according to Boley.