DGCA Air Navigation: Compass Systems (Direct & Remote) Questions
156 exam-style Compass Systems (Direct & Remote) questions for the DGCA Air Navigationpaper (CPL & ATPL). The first 12 are free below with answers and explanations — sign up free to practise all of them with progress tracking.
- Q1
The purpose of compass check swing is to:
- A measure the angle between Magnetic North and Compass North
- B cancel out the vertical component of the earth's magnetic field
- Ccancel out the horizontal component of the earth's magnetic field
- Dcancel out the effects of the magnetic fields found on board the aeroplane
Show answer
Correct answer: A. measure the angle between Magnetic North and Compass North
A compass swing is carried out to measure the residual deviation, the angle between magnetic north and compass north, on a series of headings so that it can be recorded and reduced.
- Q2
In a remote indicating compass system the amount of deviation caused by aircraft magnetism and electrical circuits may be minimised by:
- Amounting the detector unit in the wingtip
- Bthe use of repeater cards
- Cpositioning the master unit in the centre of the aircraft
- D using a vertically mounted gyroscope
Show answer
Correct answer: A. mounting the detector unit in the wingtip
Mounting the flux detector unit in a wingtip, well away from the engines, electrical circuits and cabin metal, minimises the deviation affecting a remote-indicating compass.
- Q3
An aircraft fitted with a DRMC upon landing in a northerly direction will indicate:
- Ano change
- Boscillation about north
- Ca turn towards east
- Da turn towards west
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Correct answer: A. no change
This Explanation is Coming Soon
- Q4
A direct reading compass should be swung when:
- Athere is a large, and permanent, change in magnetic latitude
- Bthere is a large change in magnetic longitude
- C the aircraft is stored for a long period and is frequently moved
- D the aircraft has made more than a stated number of landings
Show answer
Correct answer: A. there is a large, and permanent, change in magnetic latitude
A direct-reading compass should be swung when there is a large and permanent change of magnetic latitude, as this alters the deviation produced by the aircraft's magnetism.
- Q5
Which of the following will effect a direct reading compass? 1. ferrous metals 2. non-ferrous metals 3. electrical equipment
- A1 only
- B1 & 3
- C1 & 2
- Dall 3
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Correct answer: B. 1 & 3
This Explanation is Coming Soon
- Q6
The direct reading magnetic compass is made aperiodic (dead beat) by:
- Akeeping the magnetic assembly mass close to the compass point and by using damping wires
- Busing the lowest acceptable viscosity compass liquid
- Cusing long magnets
- D pendulous suspension of the magnetic assembly
Show answer
Correct answer: A. keeping the magnetic assembly mass close to the compass point and by using damping wires
The direct-reading compass is made aperiodic by keeping the magnet system's mass concentrated near the pivot, reducing its moment of inertia, and by using damping wires and liquid to quell oscillation.
- Q7
The annunciator of a remote indicating compass system is used when:
- Asynchronising the magnetic and gyro compass elements
- B compensating for deviation
- C setting local magnetic variation
- Dsetting the 'heading' pointer
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Correct answer: A. synchronising the magnetic and gyro compass elements
The annunciator, or synchronising indicator, shows when the gyro element and the flux-detected magnetic element are aligned, and it is used when synchronising the two.
- Q8
Which one of the following is an advantage of a remote reading compass as compared with a standby compass?
- A It senses the magnetic meridian instead of seeking it, increasing compass sensitivity
- BIt is lighter than a direct reading compass because it employs, apart from the detector unit, existing aircraft equipment
- C It eliminates the effect of turning and acceleration errors by pendulously suspending the detector unit
- DIt is more reliable because it is operated electrically and power is always available from sources within the aircraft
Show answer
Correct answer: A. It senses the magnetic meridian instead of seeking it, increasing compass sensitivity
A remote-reading (flux-gate) detector senses the direction of the magnetic meridian electrically rather than relying on a pivoted magnet that must physically seek it, which greatly increases sensitivity and steadiness.
- Q9
Which of the following is an occasion for carrying out a compass swing on a Direct Reading Compass?
- AAfter an aircraft has passed through a severe electrical storm, or has been struck by lightning
- BBefore an aircraft goes on any flight that involves a large change of magnetic latitude
- C After any of the aircraft radio equipment has been changed due to unserviceability
- D Whenever an aircraft carries a large freight load regardless of its content
Show answer
Correct answer: A. After an aircraft has passed through a severe electrical storm, or has been struck by lightning
A compass swing is required after a lightning strike or exposure to a severe electrical storm, because the intense magnetic fields can alter the aircraft's residual magnetism and hence the deviation.
- Q10
The main reason for mounting the detector unit of a remote reading compass in the wingtip of an aeroplane is:
- Ato minimise the amount of deviation caused by aircraft magnetism and electrical circuits
- Bto maximise the units exposure to the earth's magnetic field
- C to ensure that the unit is in the most accessible position on the aircraft for ease of maintenance
- Dby having detector units on both wingtips, to cancel out the deviation effects caused by the aircraft strucure
Show answer
Correct answer: A. to minimise the amount of deviation caused by aircraft magnetism and electrical circuits
Mounting the flux detector in the wingtip places it well away from the aircraft's own magnetism and electrical circuits, minimising the deviation it experiences.
- Q11
A factor giving an error on a direct indicating compass would be:
- Acrosswinds - particularly on east/west headings
- Bparallax due to oscillations of the compass rose
- Cacceleration on east/west headings
- Dturning through east/west headings
Show answer
Correct answer: C. acceleration on east/west headings
This Explanation is Coming Soon
- Q12
The main reason for usually mounting the detector unit of a remote indicating compass in the wingtip of an aeroplane is to:
- A reduce the amount of deviation caused by aircraft magnetism and electrical circuits
- Bfacilitate easy maintenance of the unit and increase its exposure to the Earth's magnetic field
- Cplace it in a position where there is no electrical wiring to cause deviation errors
- D place it where it will not be subjected to electrical or magnetic interference from the aircraft
Show answer
Correct answer: A. reduce the amount of deviation caused by aircraft magnetism and electrical circuits
Placing the detector unit in the wingtip keeps it clear of the aircraft's magnetism and electrical wiring, reducing the deviation acting on the compass.
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