Drive before you buy: a jet engine perspective

July 9, 2019

On February 1, 2019, after 10+ years of pursuit and hundreds of millions of dollars of investment, the Advanced Turbine Engine Company (ATEC) – a joint venture of Honeywell and Pratt & Whitney – learned that it had not been selected for the Engineering and Manufacturing Development (EMD) phase of the Army’s Improved Turbine Engine Program (ITEP). ITEP is the Army’s program to develop and field a more powerful, more fuel efficient engine for the Black Hawk and Apache helicopter fleets. The Army selected an engine proposed by ATEC’s competitor.

Presently, ATEC is asking Congress to provide funding for the Army to keep both engines in competition through the initial testing in EMD, enabling the Army to compare them side-by-side before making this 50-60 year engine selection.

When developing gas turbine engines, the U.S. Department of Defense (DoD) historically performs extensive testing of competing engines before making a final engine selection. One can look at the F119 and F135 engines, for the F-22 and F-35 fighters respectively, or the Army’s last new engine development program, the T800 engine for the Comanche. In each, testing of competing engines was performed prior to making the final engine selection.

It makes simple sense. Gas turbine engines are among the most complex machines in the world, and their design is not an exact science. Designs that predict success in some areas are often proven to be lacking once the engines are tested, hence the lengthy process that allows time to incorporate “lessons learned” from early testing later in development and prior to production.

ITEP has already been a long time in the making. In the initial Science and Technology (S&T) phase, both competitors built and tested Technology Demonstrator versions of their engines. Technology Demonstrator engines play a vital role in the engine development process, allowing for validation of critical technologies, but to call them engines is generous. They are more like “engine rigs” than “full engine prototypes,” and are certainly not flyable assets. Congress’s description of the type of funds used for technology demonstrator programs includes the following sentence: “The results of this type of effort are proof of technological feasibility and assessment of subsystem and component operability and producibility rather than the development of hardware for service use.”

Following S&T came a two-year Technology Maturation and Risk Reduction (TMRR) phase under which both engine companies performed the Preliminary Design of their intended production versions of their ITEP entries. No engine testing was required in this phase, with the results being the delivery of a successful Preliminary Design Review (PDR) and a successful fit check of a high-fidelity mockup of the engine design.

ATEC’s legislative proposal is intended to allow the Army to collect critical performance and durability test data on the competing designs prior to making this crucially important engine selection. ATEC is NOT proposing to take both competitors through the completion of the EMD phase, does NOT propose that the Army qualify both designs, and does NOT propose that the Army buy engines from both companies in production.

ATEC’s proposal instead recommends that the Army draw data from the “critical few” initial engine tests early in the testing phase of EMD, and then make a decision and never look back. Consequently, ATEC’s legislative proposal would not “double” the cost of EMD, as some have claimed, and in fact the additional funds needed are less than 1% of the total life cycle value of the ITEP acquisition.

Indeed, the Army’s initial program concept for ITEP was to do this very thing – make a choice after completion of some level of testing. Fiscal constraints brought on by the Budget Control Act and other influences changed the plan – though the Army has often reconsidered that change. ATEC has been asked many times by the Army and by Congress how it would view moving the selection decision “to the right” along the timeline and, each time, ATEC has indicated that it would “welcome the opportunity to compete its engine design against the competitors on the test stand versus a paper proposal”.

ATEC is asking Congress to relieve the Army of the fiscal constraints that have led to the current ITEP acquisition strategy by providing additional funding to allow early EMD testing of both competing engine designs. This decision is too important, too far reaching, and technically too close to make without proving the engines’ capabilities on the test stand. The Army’s own evaluation of the competing EMD proposals rated ATEC’s engine higher in the most important Technical factor and lower risk in several key Technical factors.

The ultimate goal of the ITEP engine competition should be to ensure that the U.S. warfighters get the best modern turboshaft engine that our industry and our Army know how to provide. 

Most of us wouldn’t buy a car without driving it first – it’s a minimum standard. Buying a new engine for the Army’s helicopter fleet is a much more crucial and technologically daunting decision – at the very least, the same minimum standard should apply.


Jerry Wheeler – Vice President, ATEC