With the U.S. Army looking to maintain the capability of its legacy helicopter fleet even as it moves to modernize the force with advanced rotorcraft, continued progress with a new engine program is becoming crucial to its plans.
Despite the effects of COVID-19 and a downturn in the commercial business at developer GE Aviation, the T901 Improved Turbine Engine program (ITEP) “is still ahead of the baseline schedule,” Robert Sheibley, the Army’s deputy program manager for aviation turbine engines, told the Vertical Flight Society’s virtual Forum 77 on May 11.
Development of the 3,000-shp-class T901 is on the critical path for the Army’s accelerated Future Attack Reconnaissance Aircraft (FARA). The turboshaft also is scheduled to replace the GE T700 engines powering the Army’s Boeing AH-64 Apaches and Sikorsky UH-60 Black Hawks to keep these “enduring fleets” operationally relevant.
Despite being forced into a telework environment by pandemic restrictions, the T901 program completed its critical design review (CDR) in 2020, Sheibley said. This included three virtual CDR events for the engine control system, control software and system-level engine. “This has never been done before in a virtual environment,” he said.
Completion of the CDR allowed component manufacturing and rig testing to begin. GE now is building up the first engine to test, which is planned to run later his year. Preliminary flight release is scheduled for late 2022, according to Sheibley. This will allow Bell and Sikorsky to proceed into flight testing of their competing FARA prototypes in fiscal 2023.
The milestone also will enable the Apache and Black Hawk programs to move into ITEP qualification testing, he said. First flight of the engine on the UH-60M is planned for 2022-23, according to Alan McClendon, chief engineer of the Army’s utility helicopter project office. Aircraft qualification is expected around 2024, leading to a first unit being equipped in fiscal 2027.
Boeing is not yet under contract to integrate the T901 into the AH-64E, said Lt. Col. Jeffrey Poquette, Army product manager for the Apache. “We do not expect first flight until early calendar year 2024,” he said. Operational testing is planned for 2025-26, with fielding of retrofitted aircraft in the 2027 timeframe.
With the Army now fielding the latest V6 version of the AH-64E, ITEP is the only major upgrade on the horizon for the attack helicopter, Poquette said. The upgrade will also include an improved tail-rotor blade and main-rotor head to allow use of the increased hot-and-high capability enabled by the more powerful engine.
ITEP also is the biggest upgrade in the plans for the UH-60M. Other scheduled improvements are a crashworthy fuel system, now being fielded, and a new, upturned exhaust system for increased survivability and capability.
The Army also is studying whether to leverage the UH-60V digital cockpit upgrade to provide the UH-60m with more easily updatable modular open system architecture.
An engine upgrade for the Army’s Airbus UH-72 Lakota light utility helicopters also is being considered. This would increase performance over that provided by the original Safran Arriel 1E2 turboshafts. “We are starting a study of an alternative engine and [hover out-of-ground-effect] power regain,” McClendon said. Fuel system improvements to increase crashworthiness also are planned.
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