McCONNELL AIR FORCE BASE, Kan. (AP) _ A suggestion by two former McConnell Air Force Base sergeants saved the government from buying spare engines that would have cost some $65 million.

The government thanked Master Sgt. James Niffen and Technical Sgt. Robert Riegert on Monday by presenting them with a $25,000 reward.

''It was a simple suggestion worth $12,500 each,'' said Sgt. Larry Dean, a McConnell Air Force Base spokesman.

Niffen and Riegert suggested eliminating the need to buy 22 spare engines for the KC-135 aerial refueling aircraft. Each F108-100 spare engine, which powers the tankers, is valued at about $3 million.

The $65 million savings looks pretty good considering that saving from the Suggestion Program for the entire Strategic Air Command in fiscal year 1990 was $15 million, Dean said.

''It encourages our people to put on their thinking caps and tell us how we can work smarter while saving manpower and material resources,'' said Marty Little, Suggestion Program manager at McConnell.

The sergeants noticed that three of the four KC-135 engines are configured with generators, while the fourth isn't. This meant keeping spare engines without the generator for quick replacement in the event of war or other contingencies.

''They created an ordinary-looking metal box,'' Dean said. ''Imagine a metal box you made in shop class with hoses coming out. You can actually see through the box.''

The box is called an integrated drive generator dampening stool, with connections for the hoses used on the generators.

The metal box allowed Niffen and Riegert to use virtually the same engine setup as the engine with the generator. By removing the box, all the hoses are in position for use of another generator.

Niffen has since been stationed at Soesterberg Air Base in the Netherlands and Riegert to Spangdahlem Air Base in Germany.