The U.S. Army has issued a request for proposals (RFP) for the preliminary design phase of its long-running Improved Turbine Engine Program (ITEP) to re-engine nearly 3,000 Apache and Blackhawk helicopters. Engine manufacturers have until November 9 to submit their proposals.

The ITEP aims to produce a 3,000 shaft horsepower (shp) engine that is 50 percent more powerful and 25 percent more fuel-efficient than the existing General Electric T700 engines that power Apaches and Blackhawks. The T700-GE-701D that powers the latest-model AH-64E Apache and UH-60M Blackhawk is a 1,700- to 2,000-shp-class engine. Intended as a drop-in replacement in about eight years, the ITEP engine promises improved performance in “high and hot” conditions at 6,000 feet and 95 degrees Fahrenheit, as well as longer life and lesser maintenance costs.

“This RFP release is a significant milestone in Army Aviation’s number one modernization program, and the Army is excited to begin a long-term relationship with a proven engine manufacturer,” said Lt. Col. Curt Kuetemeyer, ITEP product manager, during a conference call with reporters on September 28. “More engine power to the Blackhawk and the Apache means farther range, more time on the objective, more troops for equipment carried per mission—all resulting in a more lethal, more effective mission.”

The Army Contracting Command at Redstone Arsenal, Ala., issued the RFP on September 24. By next summer, it expects to award “up to two” contracts for the 24-month preliminary design phase, requiring manufacturers to provide their proposed designs with technical data and drawings. The Army anticipates making a “Milestone B” decision to begin engineering and manufacturing development (EMD) of one engine design in Fiscal Year 2018, then awarding an EMD contract. Low-rate initial production of the ITEP engine is scheduled for the third quarter of FY2024 and full-rate production in fourth quarter of FY2026.

The Army plans to acquire 6,215 ITEP engines to equip its fleet of 2,135 Blackhawks and 690 Apaches, including 10 percent for spares.

Leading candidates to eventually supply the ITEP engine include GE Aviation and the Advanced Turbine Engine Company (ATEC) joint venture of Honeywell and Pratt & Whitney, which have developed their respective GE3000 and HPW3000 engines under the Army’s Advanced Affordable Turbine Engine (AATE) science and technology program, a precursor to ITEP started in 2006.

“The tech base program was the Advanced Affordable Turbine Engine program, and that was intended to look at stretch goals for a turbine engine in order to see what the state of technology was currently, and whether the OEMs [original equipment manufacturers] could in fact design a turbine engine in that size and weight and volume constraint that would allow [us] to get to the shaft horsepower that we felt like we needed to do that. The tech base program proved those critical technologies were mature to a point where we felt we could go into a program of record with low risk and achieve those goals,” said Rich Kretzschmar, ITEP and Future Vertical Lift project manager.

Kretzschmar did not rule out another engine manufacturer participating in the preliminary design phase. “We feel very confident that the OEMs that are selected can build on what they demonstrated either in the AATE program or outside of the AATE program because we fully expect other engine vendors that didn’t participate in AATE to participate in this program as well.”

While Kretzschmar did not mention any companies, speculation centered on one, albeit foreign, manufacturer of helicopter engines—Turbomeca. The French company produces the RTM322 engine that powers British Apache AH Mk.1 helicopters. Turbomeca would likely need a U.S. partner if it were to participate.

In a statement following the RFP release, GE Aviation noted that it has worked with the Army on engine design and performance since the inception of the T700 in the late 1960s. Since completing full engine testing under the AATE program, it has continued maturing technologies under the service’s Future Affordable Engine Program, and through that effort recorded the highest compressor pressure ratio in company history, exceeding the 27:1 ratio demonstrated by the new GE9X engine under development for the Boeing 777X.

Honeywell touted the HPW3000 at a company-wide briefing in Washington, D.C., on September 28. The HPW3000 features a dual-spool gas generator, which the company claims is more efficient than a single-spool design. “We think the two-spool architecture is the right direction to go,” said ATEC president Craig Madden. “It’s got a 3-to-4 percent inherent advantage in SFC [specific fuel consumption] improvement, will stay on wing longer, and overall it’s the best possible engine. We estimate it will save the Army over $1 billion a year when you take into account the fuel savings and the maintenance savings of this engine.”