NASHVILLE, Tenn. — Efforts underway to develop the next-generation engine for UH-60 Black Hawk utility and AH-64 Apache attack helicopters will come to a complete stop this week as it operates under last year's funding levels, U.S. Army acquisition official Maj. Gen. Bob Marion said Thursday at the Army Aviation Association of America's annual summit.

The Army, as well as the rest of the Defense Department, is operating under a congressionally mandated continuing resolution, a mechanism to fund the government at 2016 levels instead of passing a fiscal 2017 budget. The current CR will expire April 28. House Republicans introduced a stopgap spending resolution late Wednesday to avert a partial government shutdown through May as leadership continues negotiations on a larger budget deal.

If no budget deal is made, the government could continue to operate under a year-long CR, which would have devastating effects to the U.S. military, defense officials have warned.

Two competing teams have been deeply involved over many years in developing concepts for the Army’s replacement engine for an enormous portion of the service’s helicopters. Army officials have named the Improved Turbine Engine Program, or ITEP, the No. 1 priority in aviation modernization for years, but the program was slow to move forward, slipping years behind schedule as the Army battled for funding.

The Army’s new engine will be designed to save 25 percent on fuel consumption at 3,000-shaft horsepower, as well as boost the horsepower-to-weight ratio by 65 percent and engine-design life by 20 percent.

Progress was made in the summer of 2016 when the Advanced Turbine Engine Company — a Honeywell and Pratt & Whitney team — and GE Aviation were awarded contracts to continue preliminary designs of the future engine. The service will choose one design in 2018 to continue into the engineering and manufacturing development phase.

But that could all be derailed under a CR this year or if the program is subject to sequestration in 2018.

Marion said both vendors developed schedules and are executing the program, "but again their 2017 activities are constrained at 2016 budget levels, so both those vendors this week will stop because they will exceed their 2016 funding levels."

A potential yearlong CR "further exacerbates our modernization challenges," said Marion, who also supports Army systems management. "Our lack of 2017 budget is keeping nearly 50 new starts across the Army from starting in 2017. Among those is [Future Vertical Lift]."

The Army is gearing up to kick off an analysis of alternatives ahead of establishing a program of record for its FVL helicopter in 2019. The first FVL variant is expected to fly in the early 2030s.

The analysis of alternatives "will not happen if we do not get a budget or specific relief from the beginning," Marion said.

"We also have 80 programs whose funding we will need to maintain at 2016 levels, and we won’t be able to fund at 2017 levels because we don’t have the budget," Marion said. ITEP is included in those programs, he added.