Flight Instruments

Heading indicator Vacuum relief valve 33 3 3 0 6 Overboard vent line 4 2 2I I2 5I Vacuum pump 20 20 I0 I0 I0 I0 20 20 STBY PWR TEST 4 6 SUCTION 2 8 INCHES MERCURT 0 I0 Suction Attitude indicator gauge Vacuum air filter Figure 8-20. Typical vacuum system. Turn Coordinator aircraft with the turn index. Figure 8-22 shows a picture of a The gimbal in the turn coordinator is canted; therefore, its turn coordinator. There are two marks on each side (left and gyro can sense both rate of roll and rate of turn. Since turn right) of the face of the instrument. The first mark is used to coordinators are more prevalent in training aircraft, this reference a wings level zero rate of turn. The second mark discussion concentrates on that instrument. When rolling into on the left and right side of the instrument serve to indicate or out of a turn, the miniature aircraft banks in the direction a standard rate of turn. A standard-rate turn is defined as a the aircraft is rolled. A rapid roll rate causes the miniature turn rate of 3° per second. The turn coordinator indicates only aircraft to bank more steeply than a slow roll rate. the rate and direction of turn; it does not display a specific angle of bank. The turn coordinator can be used to establish and maintain a standard-rate turn by aligning the wing of the miniature Gimbal rotation Horizontal gyro Gimbal Gyro rotation Gimbal rotation Gyro rotation Canted gyro Standard rate turn index Standard rate turn index Inclinometer Inclinometer Turn coordinator Turn-and-slip indicator Figure 8-21. Turn indicators rely on controlled precession for their operation. 8-17