A method of checking the pressure of a tire of an aircraft. A pressure reading is taken from the tire with a pressure sensor and wirelessly transmitted to a hand-held device. The hand-held device receives the pressure reading, an aircraft ID which uniquely identifies the aircraft, and a tire ID. The device then retrieves from a memory a reference pressure level associated in the memory with the aircraft ID and the tire ID; compares either the pressure reading, or an adjusted pressure based on the pressure reading, with the reference pressure level; and displays a warning if the pressure reading, or the adjusted pressure based on the pressure reading, is below the reference pressure level.