Q1. The spin axis of a directional gyro is maintained in … by means of … in an air-driven gyro and by means of a … in an electrically driven gyro.
the yawing plane; air jets; torque motor
Q2. In an air driven directional gyro the air jets are used to?
spin the gyro as well as keep it it horizontal plane
Q3. The drift of the directional gyro due to earth rotation is?
15 deg/hour at the pole.
Q4. The error in a directional gyro due to the earth’s rotation, at a mean latitude of 45°N will cause the spin axis to move by:
10.6° clockwise
Q5. The latitude nut of a directional gyro is used to?
Correct for apparent wander due to earth’s rotation.
Q6. Apparent wander drift of a directional gyro is 15 deg/hour?
At the poles.
Q7. To maintain the spin axis of the directional gyro in the yawing plane?
An erection system is used.
Q8. Apparent wander drift of a directional gyro is zero?
At the equator.
Q9. A directional gyro is checked every 15 minutes to?
Correct for total drift.
Q10. If the rotor of a directional gyro spins anticlockwise (viewed from the top), the drift due to the earth’s rotation in the southern hemisphere is?
Positive
Q11. When the DGI caging knob is pushed in?
The rotorl is locked in yawing plane and the azimuth gear is connected to the knob for correction.
Q12. The Latitude Nut on a DGI is used to?
Induce a real wander to cancel out drift due to earth’s rotation.
Q13. Real wander of a gyro is?
Variable.
Q14. A directional gyro indicator is basically a:
Correct answer is – horizontal axis tied gyro
Q15. The spin axis of a directional gyro is maintained in …………………. by means of ……………………. in an air-driven gyro and by means of a ………………………… in an electrically driven gyro.
Correct answer is – the yawing plane; air jets; torque motor
Q16. In an air-driven directional gyro the air jets are attached to:
Correct answer is – the outer gimbal
Q17. The limits of pitch and roll for a modern directional gyro are respectively:
Correct answer is – 85° and 85°
Q18. The purpose of the caging knob is:
Correct answer is – to reset the heading and to prevent toppling
Q19. Which instrument uses a vertical gyroscope fined† with a gravity erection device?
Correct answer is – Artificial horizon,
Q20. A directional gyro is: 1. A gyroscope free around two axis. 2. A gyroscope free around one axis. 3. Capable of self-orientation around an earth-tied direction. 4. Incapable of self-orientation around an earth-tied direction. The combination which regroups all the correct statements is?
Correct answer is – 1,4. Feedback – you have to manually correct it —- tied using knob
Q21. The heading reference unit of a three-axis data generator is equipped with a gyro with?
Correct answer is – 2 degrees of freedom and horizontal spin axis.
Q22. The gimbal error of the directional gyro is due to the effect of?
Correct answer is – A bank or pitch attitude of the aircraft. Feedback – when the aircraft is pitching or rolling the gyro will start experiencing the precession force and read error. this error will get cancelled out once the aircraft level out.
Q23. Gimballing error:
Correct answer is – will disappear after a turn is completed Feedback – after completing the aircraft resumes to straight and level flight , then earth vertical and aircraft vertical is same- so no gimballing error.
Q24. What error is caused by movement of the gyro relative to the earth in a DGI?
Correct answer is – Transport wander.
Q25. The heading reading on the dial of a directional gyro is subject to errors, one of which is due to the movement of the aircraft. This error?
Correct answer is – Is dependent on the ground speed of the aircraft, its true track and the average latitude of the flight.
Q26. Errors of the directional gyro are:
Correct answer is – gimballing error, random wander, apparent wander, rotor speed error, transport wander
Q27. The errors of a DGI are: 1. earth rate 2. transport wander 3. banking when pitched up 4. annual movement of poles 5. mechanical problems
Correct answer is – 1, 2, 3, & 5
Q28. A directional gyro is valid only for a short period of time. The causes of this inaccuracy are: 1. earth rotation 2. longitudinal accelerations 3. a/c motion over the earth 4. mechanical defects 5. gyro mass
Correct answer is – 1, 3 & 4
Q29. An air-driven DGI is corrected for an apparent wander at 56°N. If the aircraft is maintaining constant DGI readings:
Correct answer is – when flying south from 56°N the true heading will decrease Feedback – gyro is compensated for apparent wander at 56°N. in east west at 56 N – no error flying north form set latitude – ( -ve ) – under read – True heading increase. flying south from set latitude – ( +ve ) over read – true decrease.
Q30. Apparent drift may be corrected in a DGI by:
Correct answer is – attaching a bias weight to the inner gimbal which makes the gyro Precess in azimuth in the opposite direction to apparent wander . Feedback – Don’t get confuse- —————- Due to spring the precession is in the “”same direction” as yaw”. but due to latitude nut precession is in “‘opposite direction “” of earth rate drift wander
Q31. The directional gyro axis spins about the local vertical by 15°/hour?
Correct answer is – On the North pole.
Q32. Among the systematic errors of the “directional gyro”, the error due to the earth rotation make the north reference turn in the horizontal plane. At a mean latitude of 45° N, this reference turns by?
Correct answer is – 10.5°/hour to the right.
Q33. The formula used to calculate apparent wander of a directional gyro in the northern hemisphere is:
Correct answer is – (- 15 sine latitude in degrees per hour)
Q34. The maximum directional gyro error due to the earth rotation is?
Correct answer is – 15°/hour.
Q35. For an aircraft flying a true track of 360° between the 005° S and 005° N parallels. the precession error of the directional gyro due to apparent drift is equal to?
Correct answer is – 0°/hour.
Q36. What is the maximum gyro drift rate that can be caused by earth rotation?
Correct answer is – 15° per hour.
Q37. What will be the apparent wander on gyroscope when flying on a northerly track from 05° S to 05° N.
Correct answer is – Zero
Q38. The error in a directional gyro due to the earth’s rotation, at a mean latitude of 45°N, will cause the spin axis to move by:
Correct answer is – 10.6° clockwise