The General Accounting Office, taking note of the fact that the Army's new main battle tank, the M1, does everything except run reliably, has recommended that only a relatively small number of the tanks be purchased until the problems are solved. The Army, relying on assurances of a blue-ribbon panel that the trouble can be fixed, told the GAO it intends to go ahead and buy 720 of the new tanks this year.

The M1, built by Chrysler, "has been impressive in demonstrating its shoot-on-the-move capability, its speed, its ability to rapidly traverse rugged terrain, and the protection afforded by its armor," GAO said. But the power train--including the engine and transmission-- failed to meet the Army's requirements. In tests at Fort Knox and the Aberdeen Proving Ground, the M1s averaged 48 and 43 miles, respectively, before they needed "essential maintenance." They are supposed to be able to go 101 miles.

The GAO report seems fairly optimistic that the problems will be solved, even if it takes a new engine to solve them. In the meantime, GAO wonders, why pump all that money ($2.6 million per tank) into a proven loser that will have to be modified again and again while the engineers find fixes. The Army is planning to buy 7,058 tanks for $18.6 billion. That, however, does not reflect the ultimate cost. In testimony last summer the Army told Congress that M1s will run up $27 billion in "support costs" over their 20-year lives. (GAO Report MASAD-82-7, Dec. 15)