The F135's Proven Track Record

The debate over the alternate engine for the F-35 Lightning II spans many details – cost, reliability, safety. But sometimes lost in the discussion is the fact that there is one engine that is already powering F-35 prototypes and logging development milestones, and there is one lagging years behind.

Way out in front is the Pratt & Whitney F135 engine. It originated from the engine powering the F-22 Raptor in development and deployment for more than 15 years. The version on the Joint Strike Fighter F-35 – the F135 engine – has passed more than a dozen important development milestones over the last seven years. In the meantime, the alternate engine remains at least four years behind in the development process.

Consider the origins of the F135 – the F119-PW-100 engine. The F119 is the world’s most advanced turbofan engine powering the most technologically superior fighter aircraft the world has ever seen. The F119 recently surpassed 100,000 flight hours and features huge leaps in prognostics and health management systems and is designed to be much cheaper to maintain than other engines.

Why is the F119 engine important to the debate over the F135 engine? Because the F135 engine shares the same core as its Pratt & Whitney predecessor. That means there is already a proven track record of safety and reliability in the engine family, a critical concern for the single engine F-35.

That heritage only underscores the track record of the F135 engine itself. It powered the first Joint Strike Fighter to take to the skies on Dec. 15, 2006 and has been performing well ever since. It cleared Preliminary Design Review in May 2002 and Critical Design Review in May 2003. Delivery of the first engine to test came in October 2003 and first propulsion system to test – the Short Take-Off Vertical Landing (STOVL) version – came in April 2004. First flight for the Conventional Take Off and Landing (CTOL) was in December of 2006, followed by first flight for the STOVL in June 2008.

There were a number of additional accomplishments for the F135 engine that year, including successful aerial engine restart testing and achieving supersonic flight. When the first Lighting II’s enter operation in 2013, the F135 engine will have more than 16,000 test hours to its credit. The engine it is built upon – the F119 powering the F-22 Raptor – will have more than 500,000 flying hours.

The alternate engine sits in stark contrast. It is not based on a proven legacy engine, so there is no significant development, test or operational experience on the design. In fact, it is based on the engine that lost the competition to power the F-22. The alternate engine is four years behind the F135 engine and will have to compress development to make up for lost time, with 20 percent less window from first engine test to service release. Ask anyone with experience in advanced technology procurement and they will tell you that is not the blueprint for smooth, problem-free development. In fact, the alternate engine carries the baggage of huge risk for development delay and cost overruns.

The F135 engine’s proven track record is just one reason why President Obama, Defense Secretary Gates and others in the know have come out strongly against the alternate engine. Congress should pay attention.