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stuff because it unleashes the demons in places where we would prefer not to confront them, like bumping over the Appalachians at night in light mixed icing with a passenger asking if everything is OK.

But now we do know and we’ll have to deal with it. The way to do this, we think, is to buy the best vacuum pump you can afford, install it correctly, do the required maintenance and replace it before it explodes, as it inevitably will if it accumulates enough flight hours. But which vacuum pump actually is the best and how long might you reasonably expect it to last? To find out, we rounded up the current offerings on the pump market and put them to the test. In our view-and weve waited years to be able to say this-all these products suck. Some suck a little better than others, but all will deliver enough vacuum to stand up the gyros so theyll do their part in keeping you upright in the clouds.

Performance is less the issue here than longevity and reliability. The companies that make pumps know that the overarching concern is avoiding inflight or premature failures and theyve directed their development dollars accordingly. Aero Accessories, for instance, introduced the wear port inspection idea for its Tempest pumps, so you can look at the carbon vanes and replace the pump before it fails. Rapco followed with its own version of the wear port. Two years ago, Sigma-Tek went radical with the introduction of the Aeon pump, a design that uses a single-cylinder reciprocating piston rather than whirring carbon vanes.

We surmised that all of these pumps perform similarly and they do. But what we really wanted to know was does the more expensive piston pump have a performance advantage over the dry vane models-it does-and will it last longer? (It might, but we cant say until it accumulates more service history.)

Six Choices