What is a calibrated orifice used for in aviation instruments?

In aviation instruments, a calibrated orifice serves primarily to delay or control pressure changes within an instrument system. This device acts as a restriction that allows for a specific and measurable passage of fluid (air or liquid) through it. By carefully designing the orifice, engineers can ensure that the rate of pressure change is consistent and predictable, which is crucial for the accuracy and functionality of various instruments.

For instance, in altimeters and other pressure-based instruments, a calibrated orifice helps to dampen rapid fluctuations in pressure, providing smoother readings. This is essential for pilot operations, especially in turbulent conditions or when quick altitude changes occur, where rapid pressure variations could result in misleading instrument readings. The orifice essentially functions as a filter, contributing to the overall stability of the instrument's performance.

In contrast, the other choices pertain to different functions not associated with the calibrated orifice. Measurement of speed is typically achieved through pitot tubes or other airspeed indicators, while altitude indications derive from barometric pressure readings rather than a controlled delay in pressure changes. Adjusting air intake is a mechanical adjustment related to the engine rather than instrument calibration. Thus, the role of the calibrated orifice in delaying pressure changes is crucial for reliable instrument operation in aviation.