McCain tackles another Boeing project.

Byline: Alicia Mundy

Mar. 17--WASHINGTON--The last time Sen. John McCain started questioning the cost and structure of a massive Pentagon contract in a Senate hearing, he was initially written off as a grump. But eventually, Boeing lost a $23 billion deal to lease tankers to the Air Force.

Yesterday, in a Senate hearing, McCain tore into the nation's second-largest military program, called Future Combat Systems (FCS), which over time could cost $120 billion. This time Boeing and the Pentagon were hanging on his every syllable.

At stake is a $21 billion contract, of which Boeing, as prime contractor, gets the lion's share. The FCS program is billed by the Pentagon as an "overwhelmingly lethal" weapons system integrating battlefield computers into one vast communications …