If cost overruns were eliminated along with the modernization of already flawed — and expensive — weapons, perhaps the Pentagon would not be facing the potential sequester of funds.

Of course, that’s very easy to say but very hard to do. Two recent reports make that clear.

Let’s start with the F-22, which the Air Force has touted as the only operational fifth-generation, stealthy, air-to-air and air-to-ground fighter-bomber. Last year, the Defense Department put the cost of the current fleet of 187 at $79 billion, yet the plane has not been used in battle since the first one was turned over to the Air Force in 2005.

In 2009, the Air Force said, “The F-22 cannot be matched by any known or projected fighter aircraft,” yet today it is used primarily to fly air defense missions to protect the U.S. homeland while less costly aircraft are at war.

A new report by the Government Accountability Office that assesses selected Pentagon weapon systems discusses the last of four planned incremental modernization programs for the F-22s. The programs will add an additional $12.7 billion to its overall cost — and that is just an estimate.

The Air Force has touted the F-22 as the only operational fifth-generation, stealthy, air-to-air and air-to-ground fighter-bomber. (AP)

This is an aircraft that can’t avoid trouble. A crash in 2010 delayed the testing last year of the F-22s’ second modernization increment. Testing was halted again when all F-22s were grounded in 2011. A pilot oxygen problem has been studied as the cause of the 2010 crash, but no final cause has been determined. And some F-22 pilots still report breathing problems.

The third F-22 modernization increment includes new software for electronic protection, combat identification and upgraded communication. It will be fielded in 2014, according to the GAO.

The fourth increment, which is estimated to cost $1.5 billion, will equip the F-22 to carry two new missiles. This upgrade won’t be fielded until 2017.

One of the new missiles is the AIM-9X, the latest version of the Sidewinder short-range air-to-air missile. Ironically, like the F-22, it has been having cost growth problems. The GAO report states that the AIM-9X showed a cost increase in 2011, from $3.1 billion to $3.75 billion.

But the Defense Department’s latest selected acquisition report (SAR), released March 30, states that the AIM-9X has grown in cost to $4.7 billion. The spike is a result of ending production of the first Block I version and approving low-rate initial production of Block II.

Another program to watch is the UH-60M Black Hawk helicopter, whose older versions have been a mainstay of the Army for years. The Defense Department’s SAR has the overall program increasing by $1.5 billion over the past year, with the total buy hitting $28.9 billion. The GAO report also has the Black Hawk costs growing some 20 percent in the last five years, and more than 90 percent beyond its original estimated cost.

Why such increases? The SAR attributes most of the year-to-year increase, some $939 million, to labor costs. An additional $217 million resulted from reduction of the multiyear procurement quantities — the argument that if you buy fewer, the ones you get cost more.

The biggest cost growth is still being racked up by the F-35 Lightning II Joint Strike Fighter, in more than one way a follow to the F-22. The SAR has the aircraft’s projected overall cost rising $10.7 billion in one year, with half of that because of the slower production rate. Of course, the slowdown was partly caused by some of the internal and exotic elements of this stealth fighter-bomber still undergoing development and testing while others are in production.

Then there is the F-35’s engine. Its cost increase rose, percentage-wise, faster than the aircraft. Engine costs went up $5.6 billion to an overall cost of $63.9 billion. Most of that increase, $4 billion according to the SAR, was “due primarily to increase in initial spares.”

Put together, the total projected price for 2,457 F-35 airplanes and engines is estimated at $390 billion over the life of the program. It continues to be the most expensive weapons system ever built, but as the GAO report warns, with most of development and flight testing still ahead, “the risk of future design changes and their potential effects on the program could be significant.”

The GAO report shows the Pentagon ran up $74.4 billion in added costs last year for its 96 major defense acquisition programs. Although that number covers the entire, multiyear expenses for those programs, “it puts a different light on the $55 billion-a-year the Defense Department would have to swallow under sequester, which they say would be ‘doomsday,’ ” said Winslow T. Wheeler, who directs the Straus Military Reform Project of the Center for Defense Information. Winslow, a former national security specialist for the GAO and several Republican senators, thinks better program management is one answer.

But more than that is needed. Over the past decade, given unlimited funds, Pentagon and White House officials, with congressional encouragement and approval, spent themselves and the country into this fiscal mess chasing one exotic weapon after another — whatever the cost.

One example: the $3.7 billion spent on a now-canceled amphibious landing vehicle for the Marines. An additional $200 million is being paid to end the contract, according to the GAO. The money is gone, but the Marines are still in the market for a new landing craft.

It remains to be seen whether the Pentagon, White House and Congress can end this cycle of developing weapons, no matter the cost.

For previous Fine Print columns, go to washingtonpost.com/fedpage.