How many engine-driven vacuum pumps power the attitude indicator?

The attitude indicator in multi-engine aircraft typically relies on two engine-driven vacuum pumps for its operation. This dual setup is crucial for ensuring redundancy and reliability, particularly in critical flight instruments. Should one pump fail, the second can provide sufficient vacuum pressure to keep the attitude indicator functional, which is essential for maintaining orientation during flight, especially if other sources of attitude reference fail.

In some aircraft designs, especially more sophisticated models, a single vacuum system might power multiple instruments, but the presence of two independent pumps is a common feature that enhances safety and operational integrity. Understanding this redundancy helps pilots remain assured of their instrumentation in potentially challenging flying conditions.