No more guessing

The damaged tire goes flat on the way to your destination but there’s no way for you to know that before touching down. Had you been informed of the problem, you would have altered your destination and modified your landing placement and technique to deal with it.

Now, a new category of Bluetooth-enabled, pressure-sensing valve caps gives pilots a quick and accurate way of determining tire pressure in the air or on the ground.

These widely available products made for motorcycles, trikes, and cars simply screw on to each valve stem in place of the original cap, and they show tire pressure and temperature through a smartphone app.

I recently installed a pair of Leepee tire pressure caps ($60 on Amazon) on the two main wheels of my Van’s Aircraft RV–4, and initial results are promising.

The app allows you to set upper and lower tire pressure and heat limits, and it gives warnings if they’re out of the acceptable range. The tire pressure indications shown on the app closely matched those from traditional, mechanical pressure gauges, so measurements from the new caps seem accurate.

The main benefits are knowing the actual tire pressure, not just eyeballing the tires during preflight inspections and guessing. Low tire pressure can be difficult to recognize on light airplanes because stiff sidewalls tend to keep their form without much pressure from the inner tube. The valve stems can be difficult to reach when wheel fairings cover them, and checking tire pressure or filling them involves getting on the ground and pushing the airplane fore and aft to align the valve stems with tiny doors on the outside of the fairings. Not fun.

Drawbacks to the new technology include the fact that the tire valve must be constantly open for the sensors to work, and the tiny battery in each cap eventually will wear out and need replacement. The Bluetooth caps also are slightly larger in diameter than the metal or plastic caps they replace, so it’s possible they could get in the way of particularly tight wheel fairings.

Adrian Eichhorn, a corporate pilot and aviation mechanic with inspection authorization, said he installed pressure-sensing valve caps on his Bonanza, and they work flawlessly.

“They’re the same weight as the metal caps they replace, and they provide a real safety benefit,” Eichhorn said. “If I ever have a tire lose pressure during flight, I’ll know about it in advance and plan accordingly.” 

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