What is the function of the aneroid wafers in the altimeter?

The function of the aneroid wafers in the altimeter is to expand and contract in response to static pressure changes. Aneroid wafers are sealed metal capsules that react to variations in external air pressure. When an aircraft gains altitude, static pressure decreases, causing the wafers to expand. Conversely, as the aircraft descends and the external pressure increases, the wafers contract.

This mechanical movement is what enables the altimeter to provide a reading of the aircraft's altitude above sea level. The design allows the altimeter to convert pressure changes into a measurable readout, giving pilots essential information regarding their altitude during flight. Understanding this mechanism is crucial for safe flight operations, as altitude awareness is vital for avoiding obstacles and maintaining safe separation from other aircraft.