Those small changes in pressure are difficult to identify through visual checks alone, but larger issues are more obvious, and tires operating above or below recommended pressure are more prone to fail. Compared to the tires on a typical car, tires on your airplane are in use only for short durations (taxi, takeoff, landing), yet failure could be just as catastrophic.

As part of each preflight check, you visually inspect and check the tires—including inflation pressure and tread. Sometimes, visual inspection alone confirms a tire is deflated and must be inflated before flight. The pilot’s operating handbook lists the optimal pressure for the tires on your aircraft, which can be confirmed with a pressure gauge.

If a tire is obviously deflated, it’s important to understand the reason why. If you just inflate the tire and go flying, you risk discovering the underlying problem has gotten much worse during takeoff, landing, or while you taxi. Finding the source of the leak will help you and your mechanic decide whether inflating is adequate or if something else needs to be done, up to and including changing the tire. 

A general rule of thumb is that, for every 5 degrees Fahrenheit drop in outside air temperature, the tire pressure will fall by 1 percent. While minor fluctuations are normal, if the pressure is more than 5 percent outside of the tire's operating window, it’s time to take a closer look.

If you have a deflated tire and there isn’t any obvious sign of damage, it could be the result of a slow leak. A leak from the valve stem, for example, can happen with normal wear and tear. An inexpensive way to confirm the presence of a slow leak on the tire is to spray soapy water and watch to see if a bubble forms. Be patient, as it can take time to see results.

If you find that you’ll need to repair the tire, this is a maintenance task that certificated pilots are legally able to perform in accordance with preventive maintenance per FAR Part 43. This includes removal, installation, and repair of landing gear tires as well as replacing wheels and skis where no weight and balance computation is involved. If you choose to do the repair yourself, you may want to have a mechanic join you as an extra set of eyes and to make the most of the unique learning experience.

For more information about tire maintenance, view FAA’s resources: Advisory Circular AC 20-97B, AC 43-12A, and Part 43.