What is the role of the calibrated orifice in a vertical speed indicator?

The function of the calibrated orifice in a vertical speed indicator is to control the rate at which pressure changes occur, thereby enhancing the accuracy of the instrument's readings. When an aircraft gains or loses altitude, the vertical speed indicator responds to these changes in pressure. The calibrated orifice introduces a delay in the pressure changes, allowing the instrument to provide a smoother and more accurate indication of the vertical speed.

This feature is crucial because a rapid change in altitude could otherwise result in a jerky or momentarily inaccurate reading. By carefully controlling the airflow through the calibrated orifice, the vertical speed indicator allows for a more stable and reliable measurement, which is essential for effective altitude management and navigation during instrument flight.