The Pratt & Whitney F135 short takeoff/vertical landing (STOVL) variant propulsion system took one more step toward government certification recently with the successful completion of one of the most rigorous, demanding tests in the entire qualification program. Pratt & Whitney is a United Technologies Corp. (NYSE: UTX) company.

The high temperature margin test which took place at Arnold Engineering Development Center (AEDC) in Tennessee involves intentionally running the engine to turbine temperatures beyond design conditions while simultaneously operating the turbomachinery at or above 100 percent of design conditions.

"While these are conditions the F135 engine will not experience during normal field operations, the purpose of this test is to demonstrate design margin at the most extreme operating conditions that could possibly exist," explained Tyler Evans, Director of F135 engine programs. "This is without a doubt one of the most demanding tests for an F-35 engine and the F135 passed the test with flying colors."

The test also demonstrated the F135 propulsion system's ability to produce margin relative to thrust with this engine producing 28% more thrust than the specification requirement.

"The F135 engine continues to exceed performance expectations to deliver the most advanced, capable fifth generation fighter engine for the F-35," Evans said. "The engine that completed this test is in excellent condition. It will now complete STOVL powered lift performance qualification testing in West Palm Beach, one of the last steps prior to receiving Initial Service Release qualification from the government."

The Pratt & Whitney F135 continues its steady progress through development testing and validation into full production and sustainment. The F135 has completed more than 19,000 hours of testing and the Conventional Takeoff and Landing (CTOL) / Carrier Variant (CV) engine received Initial Service Release (ISR) in February indicating that the engine has met ISR requirements for safety, reliability, durability and performance, and is now cleared for use in the field. Pratt & Whitney has delivered all flight-test engines required for the program as well as the first ten production engines. The STOVL F135 engine is scheduled to receive ISR certification before the end of the year.

Pratt & Whitney, the only engine manufacturer producing fifth generation propulsion systems, has designed, developed and tested the F135 to deliver the most advanced fifth generation fighter engine for the U.S. Air Force, Marine Corps and Navy, as well as for eight international partner countries. The F135 is derived from proven technology of the only operational fifth generation fighter engine, the Pratt & Whitney F119 that exclusively powers the F-22 with more than 300,000 engine hours. It has been further enhanced with technologies developed in several Air Force and Navy technology demonstration programs.

The F135 propulsion system has proven through extensive ground and flight test experience that it can meet diverse aircraft requirements for armed forces around the world. The Pratt & Whitney F135 engine continues to be the only engine powering the successful Lockheed Martin F-35 Flight Test Program.