There are three gyroscopic instruments in your aircraft which are: the attitude indicator, heading indicator, and turn coordinator. The vacuum system powers the attitude indicator and the heading indicator. In case of a vacuum system failure, most turn coordinator’s are electric for a backup.
The vacuum system draws air in through a filter assembly. The air then moves through turbines in the attitude and heading indicators where it causes the gyros to spin at up to 18,000 rpm. The airflow continues on to the engine-driven vacuum pump where it is expelled. A relief valve prevents the vacuum pressure from exceeding prescribed limits.
It is the PIC’s responsibility to make sure that the altimeter system has been checked within the preceding 24 calendar months in addition to the instruments that are required for IFR are functioning properly.
