Systems (PA-28-181) PPC Practice Test

The instrument that uses gyroscopic precession to indicate both roll rate and turn rate is the Turn Coordinator. Its gyro is mounted at a slight cant relative to the airplane’s longitudinal axis, so when you roll, the gyroscope precesses in response to the roll rate and the miniature airplane tilts to show how quickly you’re rolling. As the turn continues and yaw (turn rate) grows, the precession of the spinning gyro also indicates how fast you’re turning, with the standard-turn rate aligning the symbol accordingly. A slip/skid ball is included to help show coordination. The other instruments serve different purposes: the Attitude Indicator shows bank and pitch for attitude, the Heading Indicator shows heading, and the Vertical Speed Indicator shows climb or descent rate.