The Army is investigating the hiring of several officers closely involved in the development of the DIVAD anti-aircraft gun by companies with major contracts for producing the weapon. Company executives as well as Army officials involved with DIVAD say that the men were hired for their special knowledge and not because of a desire to influence Army decisions. The investigation may well produce no concrete evidence of conflicts of interest. But the DIVAD -- for Division Air Defense -- case is an important reminder that, however well-intentioned those involved, the Pentagon's "revolving door" pushes the procurement system further toward continuing weapons systems no matter how poorly they perform.

The hiring by Ford Aeorospace and its subcontractors of eight former Army officers -- some with very direct connections to the development and testing of the controversial DIVAD -- is far from unusual. Pentagon reports show about 2,200 retired officers working for companies with large defense contracts. That number doesn't include the many civilian Pentagon workers now at those companies or all the former Pentagon workers now employed at the myriad smaller defense consulting and production firms.

The DIVAD case attracts attention, however, because the weapon has become a near-textbook case in how an expensive weapons system can continue to survive despite repeated failure to perform. The Pentagon's inspector general has charged that the Pentagon decided in 1982 to move to production of the DIVAD on the basis of test reports that did not fairly and accurately describe the gun's deficiencies. Since then, almost $2 billion has been spent. Even after Congress moved to cut off further production money last fall, the Pentagon insisted on keeping a multimillion-dollar fund to continue testing and keep production lines open. Now the Army is reported to be talking with Ford about transforming the gun into a gun-missile combination rather than let it die.

No doubt former Pentagon workers bring many useful skills to their new employers -- especially when, as at Ford, winning a big contract requires fast expansion of personnel. And who can blame officers or civilian workers, who may face limited promotion chances within the Pentagon and are often eligible for comfortable pensions if they leave, for seeking well-paid jobs in defense companies?

No impropriety can be assumed on either side of the arrangement. And yet it is difficult to be comfortable with a system in which both sides of a buy- sell arrangement have their long-term interests so firmly tied up both with each other and with the continuation of the weapons system that brought them together.