How are tire pressures checked on the ground during routine maintenance, and what is a critical concern?

• A. Visual inspection only; no measurement needed.
• B. Check tire pressures only when the tires are hot.
• C. Use calibrated tire pressure gauges per manufacturer spec; verify within tolerance and check for temperature effects.
• D. Check only after flight to avoid pressure changes.

Answer: (C)

Tire pressures should be checked with a calibrated tire pressure gauge and compared to the manufacturer’s specified value, making sure the reading falls within the allowed tolerance and taking temperature effects into account. This matters because air pressure in a tire changes with temperature, and readings taken after operation (when tires are hot) can be higher than the cold, intended operating pressure. Using a proper gauge ensures accuracy, while sticking to the manufacturer’s spec guarantees the tire is inflated to what the design expects for safe load handling and handling characteristics.

Relying on visual inspection alone can miss under- or over-inflation, and checking after the tires have been used (when hot) gives a misleading higher pressure. Checking only after flight also ignores the need to confirm the cold baseline, which is the standard reference for inflation in routine maintenance.