The Air Force has spent almost $2 billion on sophisticated electronic equipment to protect its fighter planes only to discover that most of it doesn't work and has been grounded or left unused in storage bins, according to a congressional report released yesterday.

"When the jammers were produced, none were capable of protecting aircraft as required," the General Accounting Office, the investigative arm of Congress, said in the report requested by House Armed Services Committee Chairman Les Aspin (D-Wis.).

The systems are designed to confuse or block enemy radars and trick deadly anti-aircraft missiles, giving pilots and their expensive planes a greater chance of surviving today's combat zones, where the most dangerous enemy is likely to be an invisible electronic beam or pulse.

But the GAO found that in some cases, the jammers "are being flown in a potential combat zone with inoperative components," the report said.

Who is to blame for the problems?

According to the GAO, the Air Force bought most of the systems before operational testing was finished to determine whether the equipment worked. The agency recommended in its report that a top Defense Department official ride herd on the Air Force and "establish adequate internal controls over Air Force jammer programs."

But the GAO also blamed the Defense Department: "They generally had not taken an active role in the programs because they are considered by the Defense Department to be minor programs."

The Defense Department, in a response to the GAO report, said it "concurs or partially concurs with most of the GAO findings."

But Assistant Secretary of Defense Duane P. Andrews added, "Controls are in place to ensure that systems demonstrate acceptable operational performance prior to full rate production."

That brought a terse response from GAO investigators who said they believe the findings in their report "amply demonstrate that the Defense Department's controls have not been effective . . . . "

The GAO report on four electronic jamming systems follows a series of Capitol Hill hearings and investigations into the programs. The new report also parallels complaints from some members of Congress about yet another system, the Airborne Self-Protection Jammer. Sen. David Pryor (D-Ark.) has led an effort to halt funding of the $4 billion system until "testing on the latest faulty jammer is successfully completed."

"The GAO study seems to show that the ASPJ procurement horror story is just the latest in a family of 'buy before you fly' radar jammers that don't work," Pryor said in a statement released yesterday.

Pryor and some other members of Congress have urged the Pentagon -- in this era of shrinking budgets and diminishing military threats -- to test weapon systems more thoroughly before it buys large numbers of the systems.

The GAO study also found that:

The Air Force plans to spend $1.1 billion on the ALQ-184 jammer, which didn't work when they were first deployed and were later grounded because of "an unsolved performance defect." The system is now being modified to try to fix the performance problems.

The service bought 65 of the ALQ-135 "quick reaction jammers," and proceeded to put most of them into storage because of technical problems. After an effort to correct the problems, the Air Force installed fewer than one-half the jammers and is holding the remainder "as spares or in bonded storage pending destruction because they cannot be repaired."

The ALQ-131 jammer is being flown in Europe on F-16 and other aircraft, but doesn't work because it doesn't have the proper software.