What it Looks Like: When Aircraft Tires Are Worn

An aircraft tire that has little or no tread remaining obviously needs replacing. But there are other signs of significant tire wear or damage that you should look for on every preflight inspection.

Especially on training and rental aircraft, the tire may have flat spots, which are oval-shaped areas of high wear caused by skidding the tires. The skidding results from landing with the brake pedals depressed, applying too much brake pressure on the landing rollout, or hydroplaning on a wet runway. If the tread in the area of the flat spot is worn down to the base of the grooves or so deep that some fabric shows through, the tire should be replaced. A severe tire imbalance due to flat-spotting may also necessitate replacing the tire.

If the tread on a tire is wearing unevenly but sufficient tread remains, the tire can be removed and reinstalled the other way around. The cause of any uneven wear should be corrected. Excessive shoulder wear is a sign of chronic underinflation, while excessive center-tread wear is a sign of overinflation. Deep cuts in the tread and bulges in the tire are potentially serious and should be examined by a mechanic.

Sunlight, severe weather conditions, ozone (from fluorescent lights, battery chargers, electric motors, and generators), and contaminants, including oil, gasoline, and hydraulic fluids can accelerate aging and deterioration of the rubber compound that tires are made from. Random cracking of the sidewall is also a sign of deterioration and should be investigated by a mechanic.

Healthy, serviceable tires have even tread wear; smooth, damage-free sidewalls; and proper inflation. The most important thing you can do to extend the life of expensive aircraft tires is to use the brakes sparingly, and avoid those hard landings!