By Jim Cavanaugh

Although light aircraft engines are relatively reliable, the same can’t be said of the essential accessories that make them usable in the airframe, specifically vacuum pumps, alternators, starters and magnetos, in that order. Of the four, vacuum pumps and alternators are the most likely to ruin a trip by failing at the least opportune moment.

Innovative suppliers have responded to the frustration of premature vacuum pump failure with new designs and backup strategies to include electric attitude gyros. Now, alternators are getting some attention. At Oshkosh in recent years, we’ve noticed a profusion of new alternator designs that are lighter, smarter and more efficient than the automotive adaptations found on the…