Aircraft Instruments

Exam 1, 56 Questions, 58 marks; time allowed 90 minutes

Q1 In a standard atmosphere and at the sea level, the calibrated airspeed (CAS)
is :

(a) lower than the true airspeed (TAS).

(b) equal to the true airspeed (TAS).
(c) independent of the true airspeed (TAS).
(d) higher than the true airspeed (TAS). (1)

Q2 In a non-pressurized aircraft, if one or several static pressure ports are

damaged, there is an ultimate emergency means for restoring a practically
correct static pressure intake :

(a) breaking the rate-of-climb indicator glass window

(b) slightly opening a window to restore the ambient pressure in the cabin
(c) descending as much as possible in order to fly at a pressure as close to
1013.25 hPa as possible
(d) calculating the ambient static pressure, allowing for the altitude and QNH and
adjusting the instruments (1)

Q3 The atmospheric pressure at FL 70 in a "standard + 10" atmosphere is:

(a) 781.85 hPa.

(b) 942.13 hPa.
(c) 1 013.25 hPa.
(d) 644.41 hPa. (2)

Q4 The altimeter is fed by:

(a) differential pressure

(b) static pressure
(c) dynamic pressure
(d) total pressure (1)

Q5 The altitude indicated on board an aircraft flying in an atmosphere where all

the atmosphere layers below the aircraft are cold is :

(a) equal to the standard altitude.

(b) lower than the real altitude.
(c) the same as the real altitude.
(d) higher than the real altitude. (1)

Q6 When descending through an isothermal layer at a constant Calibrated

Airspeed (CAS), the True Airspeed (TAS) will:

(a) decrease
(b) increase at a linear rate
(c) remain constant
(d) increase at an exponential rate (1)

Bristol Groundschool Instruments Exam 1.1

Q7 VLO is the maximum:

(a) speed at which the landing gear can be operated with full safety.
(b) flight speed with landing gear down.
(c) speed with flaps extended in a given position.
(d) cruising speed not to be exceeded except in still air with caution. (1)

Q8 Considering the maximum operational Mach number (MMO) and the maximum
operational speed (VMO), the captain of a pressurized aircraft begins his
descent from a high flight level. In order to meet his scheduled time of arrival,
he decides to use the maximum ground speed at any time of the descent. He
will be limited:

(a) initially by the VMO, then by the MMO below a certain flight level
(b) by the MMO
(c) by the VMO in still air
(d) initially by the MMO, then by the VMO below a certain flight level (1)

Q9 The response time of a vertical speed detector may be improved by adding a:

(a) correction based on an accelerometer sensor.

(b) bimetallic strip
(c) return spring
(d) second calibrated port (1)

Q10 In An Air Data Computer (ADC), aeroplane altitude is calculated from:

(a) The difference between absolute and dynamic pressure at the fuselage
(b) Measurement of outside air temperature (OAT)
(c) Measurement of elapsed time for a radio signal transmitted to the ground
surface and back
(d) Measurement of absolute barometric pressure from a static source on the
fuselage (1)

Q11 The basic properties of a gyroscope are:

1. The gyro's weight.

2. The rigidity in space.
3. The inertia.
4. The high RPM.
5. The precession

The combination of correct statements is :

(a) 3,4
(b) 2,5
(c) 2,3,5
(d) 1,3,5 (1)

Bristol Groundschool Instruments Exam 1.2

Q12 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:

(a) 15°/hour to the right.

(b) 7.5°/hour to the right.
(c) 7.5°/hour to the left.
(d) 10.5°/hour to the right. (2)

Q13 Compared with a conventional gyro, a laser gyro:

(a) consumes a lot of power

(b) has a longer life cycle
(c) is influenced by temperature
(d) has a fairly long starting cycle (1)

Q14 A slaved directional gyro derives its directional signal from:

(a) a direct reading magnetic compass.

(b) the flight director.
(c) the flux valve.
(d) the air-data-computer. (1)

Q15 The gyromagnetic compass torque motor:

(a) causes the directional gyro unit to precess

(b) causes the heading indicator to precess
(c) feeds the error detector system
(d) is fed by the flux valve (1)

Q16 When an aircraft has turned 270 degrees with a constant attitude and bank,
the pilot observes the following on a classic artificial horizon:

(a) too much nose-up and bank too high.

(b) too much nose-up and bank too low.
(c) attitude and bank correct.
(d) too much nose-up and bank correct. (1)

Q17 On the ground, during a right turn, the turn indicator indicates:

(a) needle in the middle, ball to left

(b) needle to the right, ball to left
(c) needle to the right, ball to right
(d) needle in the middle, ball to right (1)

Q18 An aircraft is flying at 120 kts true airspeed (VV), in order to achieve a rate 1 turn the
pilot will have to bank the aircraft at an angle of:

(a) 18º
(b) 12º
(c) 36º
(d) 30º (1)

Bristol Groundschool Instruments Exam 1.3

Q19 While inertial platform system is operating on board an aircraft, it is
necessary to use a device with the following characteristics, in order to
keep the vertical line with a pendulous system:

(a) without damping and a period of about 84 seconds

(b) with damping and a period of 84 seconds
(c) with damping and a period of about 84 minutes.
(d) without damping and a period of about 84 minutes (1)

Q20 In order to align a strapdown inertial unit, it is required to insert the local
geographical coordinates. This is necessary to:

(a) Position the computing trihedron with reference to earth.

(b) Check operation of laser gyros.
(c) Determine magnetic or true heading.
(d) Re-erect laser gyros. (1)

Q21 In the Northern hemisphere, during deceleration following a landing in a

Westerly direction, the magnetic compass will indicate:

(a) an apparent turn to the South.

(b) an apparent turn to the North.
(c) no apparent turn.
(d) a heading fluctuating about 270°. (1)

Q22 A pilot wishes to turn left on to a southerly heading with 20° bank at a latitude
of 20° North. Using a direct reading compass, in order to achieve this he
must stop the turn on an approximate heading of:

(a) 190°
(b) 160°
(c) 200°
(d) 170° (1)

Q23 During the approach, a crew reads on the radio altimeter the value of 650 ft.
This is an indication of the true:

(a) height of the aircraft with regard to the runway.

(b) altitude of the aircraft.
(c) height of the lowest wheels with regard to the ground at any time.
(d) height of the aircraft with regard to the ground at any time. (1)

Q24 The Primary Flight Display (PFD) displays information dedicated to:

(a) engines and alarms.

(b) systems.
(c) piloting.
(d) weather situation. (1)

Bristol Groundschool Instruments Exam 1.4

Q25 All the last generation aircraft use flight control systems. The Flight
Management System (FMS) is the most advanced system; it can be defined
as a:

(a) management system optimized in the horizontal plane

(b) global 2-D Flight Management System
(c) global 3-D Flight Management System
(d) management system optimized in the vertical plane (1)

Q26 When the altitude acquisition mode is engaged on a jet transport airplane
equipped with autopilot (AP) and auto-throttle (ATS) systems the:

(a) true airspeed (TAS) is maintained constant by the auto-throttle system.

(b) indicated airspeed (IAS) is maintained constant by the auto-throttle system.
(c) indicated airspeed (IAS) is maintained constant by the autopilot by means of
elevator.
(d) true airspeed (TAS) is maintained constant by the autopilot by means of
elevator. (1)

Q27 Mode "Localizer ARM" active on Flight Director means:

(a) Localizer ALARM, making localizer approach not authorized

(b) Coupling has occurred and system provides control data to capture the
centreline
(c) Localizer is armed and coupling will occur when flag warning disappears
(d) System is armed for localizer approach and coupling will occur upon capturing
centre line (1)

Q28 The "heading hold" mode is selected on the flight director (FD) with a course
to steer of 180°. Your aircraft holds a heading of 160°. The vertical bar of the
FD:

(a) cannot be centred

(b) is centred if the aircraft is on optimum path to join heading 180°
(c) is centred if the aircraft has a starboard drift of 20°
(d) is centred if the aircraft has a port drift of 20° (1)

Q29 The aim of the flight director is to provide information to the pilot:

(a) allowing him to return to a desired path according to a 45° intercept angle.
(b) allowing him to return to a desired path according to a 30° intercept angle.
(c) allowing him to return to a desired path in an optimal way.
(d) about his position with regard to a radioelectric axis. (1)

Q30 The Head Up Display (HUD) is a device allowing the pilot, while still looking
outside, to have:

(a) a monitoring only during Cat III precision approaches.

(b) a synthetic view of the instrument procedure.
(c) a flying and flight path control aid.
(d) a monitoring of engine data. (1)

Bristol Groundschool Instruments Exam 1.5

Q31 An automatic landing system necessitating that the landing be continued
manually in the case of a system failure during an automatic approach is
called "FAIL...."

(a) "OPERATIONAL"
(b) "SAFE"
(c) "REDUNDANT"
(d) "PASSIVE" (1)

Q32 A closed loop control system in which a small power input controls a much
larger power output in a strictly proportionate manner is known as:

(a) an amplifier.
(b) a feedback control circuit.
(c) an autopilot.
(d) a servomechanism. (1)

Q33 On an autopilot coupled approach, GO AROUND mode is engaged:

(a) by the pilot pushing a button located on the throttles.

(b) by the pilot selecting G.A. mode on the thrust computer control panel.
(c) automatically in case of an autopilot or flight director alarm.
(d) if the aircraft reaches the decision height selected on the radio altimeter at a
higher speed than the one selected. (1)

Q34 The engagement of an autopilot is not possible when:

1. there is a fault in the electrical power supply

2. the controlled-turn knob is not set to centre-off
3. there is a synchronization fault in the pitch channel
4. there is a fault in the attitude reference unit

The combination regrouping all the correct statements is:

(a) 1, 2, 4.
(b) 2, 3, 4.
(c) 1, 3, 4.
(d) 1, 2, 3, 4. (1)

Q35 When using the autopilot, the function of the pitch channel automatic trim is
to:

1. cancel the hinge moment of the elevator

2. ease as much as possible the load of the servo-actuator
3. restore to the pilot a correctly trimmed airplane during the autopilot
disengagement

The combination regrouping all the correct statements is:

(a) 1 and 2.
(b) 1, 2 and 3.
(c) 3.
(d) 1 and 3. (1)

Bristol Groundschool Instruments Exam 1.6

Q36 During a Category ll automatic approach, the height information is supplied by the:

(a) altimeter
(b) radio altimeter
(c) GPS (Global Positioning System)
(d) encoding altimeter (1)

Q37 A pilot has to carry out a single-pilot IFR flight on a light twin-engined aircraft
for cargo transport. The purpose of the automatic pilot is at least to hold the:

(a) heading
(b) altitude
(c) heading, to hold the altitude and to have a radio axis tracking function
(d) heading and to hold the altitude (1)

Q38 In the automatic trim control system of an autopilot, automatic trimming is

normally effected about the:

(a) pitch axis only.

(b) roll and yaw axes only.
(c) pitch roll and yaw axes.
(d) pitch and roll axes only. (1)

Q39 Among the following functions of an autopilot, those related to the aeroplane
stabilization are:

1. pitch attitude holding

2. horizontal wing holding
3. displayed heading or inertial track holding
4. indicated airspeed or Mach number holding
5. yaw damping
6. VOR axis holding

The combination regrouping all the correct statements is:

(a) 2, 4, and 5.
(b) 1, 2 and 5.
(c) 1, 2, 3 and 6.
(d) 3, 4, 5 and 6. (1)

Q40 An aeroplane is in steady cruise at flight level 270. The autothrottle maintains
a constant calibrated airspeed. If the total temperature increases, the Mach
number:

(a) decreases.
(b) decreases if the outside temperature is higher than the standard temperature,
increases if lower.
(c) remains constant.
(d) increases. (1)

Bristol Groundschool Instruments Exam 1.7

Q41 Alarms are standardised and follow a code of colours. Those requiring
action but not immediately, are signalled by the colour:

(a) flashing red

(b) amber
(c) red
(d) green (1)

Q42 The purpose of the altitude alert system is to generate a visual and aural
warning to the pilot when the:

(a) aeroplane altitude is equal to the decision altitude.

(b) proximity to the ground becomes dangerous.
(c) altimeter setting differs from the standard setting above the transition altitude.
(d) aeroplane altitude differs from a selected altitude. (1)

Q43 The GPWS (Ground Proximity Warning System) releases a warning in the
following cases:

1. excessive rate of descent

2. excessive ground proximity rate
3. loss of altitude after take-off or go-around
4. abnormal gear/flaps configuration
5. excessive deviation under the glidepath
6. abnormal airbrakes configuration

The combination regrouping all the correct statements is:

(a) 1, 2, 3, 4, 5
(b) 2, 4, 5, 6
(c) 1, 2, 3, 4, 5, 6
(d) 3, 4, 5, 6 (1)

Q44 If an aircraft is flying (with flaps and landing gear retracted) in proximity to
terrain and its GPWS (Ground Proximity Warning System) get activated,
because it is detecting that the aeroplane has an excessive rate of descent,
the system provides the following aural warning signals:

(a) "DON'T SINK, DON'T SINK"

(b) "TERRAIN, TERRAIN" followed by "WHOOP WHOOP PULL UP" (twice)
(c) "TOO LOW, TERRAIN" (twice) followed by "TOO LOW GEAR" (twice)
(d) "SINK RATE, SINK RATE" followed by "WHOOP WHOOP PULL UP" (twice)
(1)

Q45 The principle of the TCAS (Traffic Collision Avoidance Systems) is based on
the use of:

(a) F.M.S. (Flight Management System)

(b) air traffic control radar systems
(c) transponders fitted in the aircraft
(d) airborne weather radar system (1)

Bristol Groundschool Instruments Exam 1.8

Q46 A "traffic advisory" is displayed on the display device of the TCAS 2
(Traffic Collision Avoidance System) by:

(a) a blue or white full lozenge.

(b) a red full square.
(c) a blue or white empty lozenge.
(d) an orange/amber full circle. (1)

Q47 The calculator combined with the stick shaker system of a modern transport
airplane receives information about the:

1. angle of attack
2. engine R.P.M.
3. configuration
4. pitch and bank attitude
5. sideslip

The combination regrouping all the correct statements is:

(a) 1, 2, 3 and 4.
(b) 1 and 3.
(c) 1, 2, 3, 4 and 5.
(d) 1 and 5. (1)

Q48 The angle of attack transmitters placed laterally on the forward part of the
fuselage supply an electrical signal indicating:

1. the angular position of a wind vane

2. a differential pressure in a probe, depending on the variation of the angle
of attack
3. a differential pressure in a probe, depending on the variation of the speed

The combination regrouping all the correct statements is:

(a) 1, 3.
(b) 1, 2.
(c) 1, 2, 3.
(d) 2, 3. (1)

Q49 The oncoming stall of a large transport airplane appears in the form of:

(a) control stick vibrations simulating natural buffeting.

(b) an orange light on the warning display.
(c) a natural buffeting which occurs prior to the simulated buffeting.
(d) a bell type warning. (1)

Q50 Flight recorder duration must be such that flight data, cockpit voice and
sound warnings may respectively be recorded during at least:

(a) 20 hours for flight data, 15 minutes for cockpit voices and warnings horns.
(b) 48 hours for flight data, 60 minutes for cockpit voices and warnings horns
(c) 25 hours for flight data, 30 minutes for cockpit voices and warnings horns.
(d) 24 hours for flight data, 60 minutes for cockpit voices and warnings horns.
(1)

Bristol Groundschool Instruments Exam 1.9

Q51 A "Bourdon Tube" is used in:

(a) pressure sensors

(b) vibration detectors
(c) smoke detectors
(d) turbine temperature probes (1)

Q52 A manifold pressure gauge of a piston engine measures:

(a) fuel pressure leaving the carburettor.

(b) vacuum in the carburettor.
(c) absolute pressure in intake system near the inlet valve.
(d) absolute air pressure entering the carburettor. (1)

Q53 The electromotive force of a thermocouple is not modified if one or several

intermediate metals are inserted in the circuit provided that:

(a) these metals are maintained at a temperature higher than that of the cold
source.
(b) these metals are maintained at a temperature lower than that of the cold
source.
(c) contact points are maintained at equal temperature between these different
metals.
(d) these metals are not the same as those constituting the thermocouple. (1)

Q54 The main advantage of a ratiometer-type temperature indicator is that it:

(a) is simple.
(b) can operate without an electrical power supply.
(c) is very accurate.
(d) carries out an independent measurement of the supply voltage. (1)

Q55 The advantages of single-phase A.C. generator tachometer are:

1. the suppression of spurious signals due to a D.C. generator commutator

2. the importance of line resistance on the information value
3. the independence of the information in relation to the airborne electrical
power supply
4. the ease of transmission of the information

The combination regrouping all the correct statements is:

(a) 1, 3.
(b) 1, 2, 3, 4.
(c) 2, 3, 4.
(d) 2, 4. (1)

Q56 The electronic tachometer sensor is composed of:

(a) the rotor of a single phase A.C. generator.

(b) the rotor of a three-phase A.C. generator.
(c) a notched wheel rotating in front of an electro-magnet.
(d) a circular magnet with four poles. (1)

Bristol Groundschool Instruments Exam 1.10

 Aircraft Instruments

Exam 1, 56 Questions. 58 marks, Time allowed: 90 minutes.

A B C D A B C D A B C D
1 21 41
2 22 42
3 23 43
4 24 44
5 25 45
6 26 46
7 27 47
8 28 48
9 29 49
10 30 50
11 31 51
12 32 52
13 33 53
14 34 54
15 35 55
16 36 56
17 37
18 38
19 39
20 40

Name:

Bristol Groundschool Instruments Exam 1.11

 Intentionally blank

Bristol Groundschool Instruments Exam 1.12

Instruments Exam 1 - Answers

1. (b) 21. (a) 41. (b)

2. (a) 22. (b) 42. (d)
3. (a) 23. (c) 43. (a)
4. (b) 24. (c) 44. (d)
5. (d) 25. (c) 45. (c)
6. (a) 26. (b) 46. (d)
7. (a) 27. (d) 47. (b)
8. (d) 28. (b) 48. (b)
9. (a) 29. (c) 49. (a)
10. (d) 30. (b) 50. (c)
11. (b) 31. (d) 51. (a)
12. (d) 32. (d) 52. (c)
13. (b) 33. (a) 53. (c)
14. (c) 34. (d) 54. (d)
15. (a) 35. (b) 55. (a)
16. (a) 36. (b) 56. (c)
17. (b) 37. (d)
18. (a) 38. (a)
19. (c) 39. (b)
20. (a) 40. (c)

Worked Answers

Q1. The ASI is calibrated to the density of air at sea level in a standard atmosphere, i.e.
1225 gm/m3. Answer (b)

Q2. In an unpressurised aircraft the pressure inside the aircraft will be much the same as
the pressure outside. By breaking the glass on one of the pressure instruments
cabin pressure is introduced into the static system – providing there is an
interconnected static system ! Answer (a)

Q3. 7,000 ft @ 30 ft per hPa = 233.3 hPa. 1013.25 – 233.3 = 779.95 hPa at 7,000 ft.
Near enough ! Answer (a)

Q4. Come on !! Answer (b)

Q5. In cold air the a given pressure will be lower so the indicated altitude will be higher
than the real altitude. Answer (d)

Q6. As you descend air density will increase, so at constant CAS, TAS will decrease.
Answer (a)

Q7. VLO is maximum speed at which gear can be operated (up or down). VLE is
maximum speed at which aircraft can be flown with gear locked down. Answer (a)

Q8. At altitude the speed reference is Mach No. but at some point in the descent the
speed reference changes to IAS. Answer (d)

Q9. The accelerometer (dash pots) respond to ‘G’ forces in the climb and descent.
Answer (a)

Q10. Same as the altimeter. Answer (d)

Bristol Groundschool Instruments Exam 1.13

Q11. The properties of a gyro are precession and rigidity Answer (b)

Q12. Drift due to Earth Rate will make the gyro rotate clockwise (to the right) in the
northern hemisphere at a rate of 15 x sin lat º/hr = 15 x sin45º = 10.05º/hr
Answer (d)

Q13. Laser gyros are very efficient and ready for use in an instant (no STBY mode).
Answer (b)

Q14. The flux valve (detector unit) senses the Earth's magnetic field. Answer (c)

Q15. The torque motor causes the gyro to precess in the vertical plane (topple) to keep its
spin axis horizontal. Answer (a)

Q16. 'Classic artificial horizon' means an air driven instrument. Throughout a turn the is
too much pitch up; maximum at 180º. The angle of bank over reads at 90º, is
correct at 180º and over reads at 270º. Answer (a)

Q17. The needle shows the direction of turn but, without any bank (on the ground) the ball
shows that you are skidding out of the turn. Answer (b)

Q18. The angle of bank required for a rate 1 turn is 10% of TAS + 7º; 12 + 7 = 19º.
Answer (a)

Q19. Schuler loop oscillations have a period of 84.4 minutes and are damped out to
prevent errors in the INS/IRS. Answer (c)

Q20. The IRS must have its position confirmed in order to get itself aligned correctly.
Answer (a)

Q21. For the northern hemisphere remember ANDS; Accelerate = apparent turn to North,
Decelerate = apparent turn to South. Answer (a)

Q22. For the northern hemisphere remember UNOS; Under turn through North, Over turn
through South. In this case the pilot must over turn through South for about 20º.
Answer (b)

Q23. Radio altimeter gives the height of the lowest wheels above the ground immediately
below the aircraft. Answer (c)

Q24. PFD relates to driving the aeroplane. Answer (c)

Q25. It works in L-Nav (lateral navigation) and V-Nav (vertical navigation). Answer (c)

Q26. The ‘ALT ACQ’ phase is not selectable; it just happens close to the selected altitude.
In ‘ALT ACQ’, therefore, the autopilot pitch channel has to capture the altitude and
the autothrottle will control speed. Not well worded; might be worth an appeal if it
comes up so let us know. Answer (b)

Q27. ARM means it is ready for use. Answer (d)

Bristol Groundschool Instruments Exam 1.14

Q28. The given answer is (b) but none of these answers are correct. If HDG HOLD is
engaged on 160º then the FD roll bar will be central and the a/c will maintain 160º
Answer (b) APPEAL IT!

Q29. Answer (c)

Q30. ……. while looking out of the window. This answer is not very good but the
question has not been used by the CAA in the UK exams; please let us know if it
crops up. Answer (b)

Q31. If the autoland cannot be continued after a failure it is a “fail passive” system; if the
autoland can be continued it is “fail active” or “fail operational”. Answer (d)

Q32. Answer (d)

Q33. The TOGA button. Answer (a)

Q34. Any of the above. Answer (d)

Q35. Any of the above. Answer (b)

Q36. Rad alt. For Cat. II & III. Answer (b)

Q37. Control in pitch and roll is all that is required. Answer (d)

Q38. Auto trim is normally only in pitch. Answer (a)

Q39. Stabilization in pitch roll and yaw. Answer (b)

Q40. At constant CAS if temperature increases then TAS will increase. Also local speed
of sound (LSS) will increase. Mach number is the ratio of TAS to LSS and if they
both increase the Mach number remains constant. Funny old thing but try it on the
nav. Computer. Answer (c)

Q41. Red must be actioned immediately, amber must be actioned, green is information.
Answer (b)

Q42. Answer (d)

Q43. Modes 1 to 5. Airbrakes not covered by GPWS. Answer (a)

Q44. Mode 1 alert. Answer (d)

Q45. Transponders. Answer (c)

Q46. TA = solid yellow/amber circle. Answer (d)

Q47. Angle of attack and configuration are the most important factors. Airspeed and
engine thrust (not RPM) are also inputs but not offered here. Answer (b)

Q48. Two way of sensing angle of attack are the vane type sensor and the ADD probe.
Answer (b)

Bristol Groundschool Instruments Exam 1.15

Q49. There is a clue in Q47. Answer (a)

Q50. Fact ! Answer (c)

Q51. It measures relatively high pressures. Answer (a)

Q52. It is the pressure in the manifold which is of interest; not the pressure around the
carburetor. Answer (c)

Q53. If there is no temperature difference there will be no stray EMF arising. Answer (c)

Q54. The other option, the galvanometer, requires stable voltage for accuracy. Answer (d)

Q55. Statements 1 & 3 are good. Line resistance is not important and transmission of
information is no easier than other systems. Answer (a)

Q 56. This is the induction tachometer with its phonic wheel. Answer (c)

Bristol Groundschool Instruments Exam 1.16