WASHINGTON – The Army’s Comanche helicopter was envisioned as “the quarterback of the digital battlefield,” a technologically superior aircraft that could hide from enemies, operate at night and in bad weather, and travel farther than any other helicopter.

Gen. Richard Cody, a former vice chief of staff of the Army, called it the “most flexible, most agile” aircraft the country had ever produced.

In 2000, it ranked as the most important planned buy for the Army. Four years later, the program — which had consumed close to 20 years of work and nearly $6 billion — was abruptly shuttered.

It is one of 22 major Army weapons programs that have been canceled since 1995, ringing up a price tag of more than $32 billion for equipment that was never built. A new study commissioned by the Army, though not publicly released, condemns the service’s efforts as “unacceptable.”

The study is the latest indication that the Pentagon — and the defense industry, in turn — is undergoing a seismic shift in its approach to new programs.

As pressures mounted in Iraq and Afghanistan, the military retreated from its ambitions of building multibillion-dollar, technologically superior systems. Instead, it was forced to make better use of tried-and-true equipment.

For almost a decade, the Defense Department saw its budgets boom — but didn’t make the kind of technological strides that seemed possible.

“Since 9/11, a near doubling of the Pentagon’s modernization accounts — more than $700 billion over 10 years in new spending on procurement, research and development — has resulted in relatively modest gains in actual military capability,” Defense Secretary Robert Gates said in an address last week.

That outcome, he said, is both “vexing and disturbing.”

Gone are the days of “no-questions-asked funding requests,” he said. The Defense Department must make do with less. It is focusing on fixing up older equipment and taking a more measured approach to weapon development.

The shifting strategies and a shrinking defense budget have triggered the biggest restructuring in the defense industry since the end of the Cold War.

Contractors big and small have been rethinking their portfolios and buying and selling accordingly. Northrop Grumman, for instance, spun off its shipbuilding unit. And Robert Stevens, chief executive of Lockheed Martin, last week said the company’s workforce, which has shrunk by 20,000 since 2009, “may well continue to decline.”

In recent years, the Pentagon has killed off some of its most heralded — and most pricey — weapons programs, and many of those that remain are not certain to move forward.

“We’ve had 10 years of wars. We’ve had a fair amount of money available to the department,” said Thomas Hawley, deputy undersecretary of the Army. “It’s just time now, with at least one war winding down and another we hope will be winding down and funding definitely coming down, to take a pause, relook where we are and go forward from there in a thoughtful way.”

IRAQ, AFGHANISTAN CHANGE NEEDS

As the Army began developing the Comanche helicopter in the 1980s, it was riding high on the success of what are known as the “big five” major weapons systems: the Abrams tank, Bradley infantry fighting vehicle, Apache attack helicopter, Black Hawk utility helicopter and Patriot missile system, all of which are used today.

The Army, launching the Comanche with the Cold War in mind, imagined a new kind of helicopter able to stealthily detect well-equipped enemies. After a complex acquisition process, the military commissioned the team of Boeing and Sikorsky to build the Comanche. The Army eventually settled on buying 650 Comanches for about $39 billion.

But as the Army entered unconventional wars in Afghanistan and Iraq, it suddenly didn’t need the best, most capable system available; it simply needed aircraft — and fast.

“The Comanche helicopter was a good helicopter. . . . We hadn’t had one like that before,” Hawley said. “It just was eating so much of the budget.”

Nearly $6 billion was already spent, but the Army and the Pentagon agreed in 2004 that if the program were canceled, the service could redirect the roughly $15 billion budgeted for the Comanche over the next seven years to aircraft already in production, such as Apache and Black Hawk helicopters and unmanned drones.

The cancellations have not stopped there. The helicopter developed to replace Comanche — known as the Armed Reconnaissance Helicopter program — was abandoned in 2008 after its price ballooned well past its budget. According to the Army study, that second effort cost another $535 million.

More recently, the Army experienced its steepest loss with the end of its Future Combat Systems (FCS) effort, billed as the Army’s most important and transformative modernization initiative.

The complex program included a family of manned vehicles, a range of unmanned air and ground systems and sophisticated radios, all tied to a single network and intended to give soldiers a superior view of the battlefield.

The idea was that the Army wouldn’t lose a fight if it could see everything its enemy was doing.

Launched at the tail end of the 20th century, the program faced serious technological failures. At the same time, Pentagon leaders, including Gates, began raising fundamental concerns about whether the systems would be successful in wars like Iraq, in which the enemy fought amid a civilian population with unsophisticated but lethal weapons — the homemade bomb that could destroy a Humvee.

The FCS program was slowly dissolved. The loss was monumental — $19 billion as calculated in the Army’s new study, making it by far the single most expensive cancellation.

“My experience in government is, when you want to change something all at once and create a whole new thing, you usually end up with an expensive disaster on your hands,” Gates said. “Maybe Google can do something revolutionary, but we don’t have the agility to do that.”

Gates set out to single-handedly upend the traditional idea of how the military develops and buys its largest weapons.

He criticized the military, saying it had believed for far too long that “Iraq and Afghanistan were exotic distractions that would be wrapped up relatively soon,” meaning the services did not need to change their buying processes or dismantle long-range procurement plans.

ARMY OFTEN THINKS TOO BIG

The end of major weapons programs is clearly linked to the pressures on funding and demand created by the wars in Afghanistan and Iraq. But analysts also point to the scope of the programs.

Loren Thompson, a defense industry consultant at the Lexington Institute, blames the failures on the complexity the military sought in modern programs.

For instance, a tank wouldn’t just shoot; it would also allow soldiers to view the battlefield, see the status of other weapon systems and communicate with other soldiers.

“Anything that is a system of systems is probably too complicated,” Thompson said. “The technology takes too long to develop, and the political system runs out of patience.”

The Army often thinks too big when designing its programs, said the new study, a wide-ranging analysis chaired by Gilbert Decker, a former Army acquisition chief, and retired Gen. Louis Wagner, who headed Army Materiel Command. The study points to the service’s failure to properly set the parameters for new equipment.

A segment of the military wants program baselines to “only state the operational need and not be constrained by either technology or cost,” the study said.