compass

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Questions and Answers

Which materials should not be left near a direct reading compass during calibration to ensure accuracy?

Non-magnetic tools

Wooden objects

Plastic items

Ferrous materials (correct)

What is the recommended distance to keep the datum compass away from any magnetic interference during a compass swing?

100 meters

75 meters

50 meters (correct)

25 meters

Which is necessary when performing a compass swing at a surveyed site?

The aircraft must be in a normal in-flight condition (correct)

All tools must be metallic

A backup compass must be present

An engine runner is not needed

What should be avoided near hangars or large buildings during a compass swing?

Electronic transmitting devices Signup and view all the answers

What is the primary purpose of a compass check swing procedure?

To check serviceability Signup and view all the answers

Why is it important to use non-magnetic tools during compass adjustments?

To ensure accuracy during calibration Signup and view all the answers

What is the primary function of the magnetic compass in aircraft?

To display the direction of the aircraft relative to magnetic north Signup and view all the answers

Which statement accurately describes the relationship between the Earth's magnetic poles and the compass?

A freely suspended magnet aligns itself with the Earth's magnetic flux. Signup and view all the answers

What role does a remote indicating compass system play in aircraft that also use radio navigational aids?

It is used exclusively for backup in case of primary system failure. Signup and view all the answers

Which component of magnetic force is particularly useful for determining magnetic heading for an aircraft?

Horizontal component Signup and view all the answers

What generally happens to a freely suspended permanent magnet at any point on Earth's surface?

It aligns itself with the Earth's magnetic lines of flux. Signup and view all the answers

What is one of the key precautions involved with compass systems in aircraft?

Ensuring metallic objects are kept away from the compass. Signup and view all the answers

When should compass compensation and adjustment be performed?

After airframe or engine component changes Signup and view all the answers

Which method is NOT used for carrying out a compass swing?

Fuel flow measurement Signup and view all the answers

What effect does the flux valve's mounting position have?

It is influenced by magnetic materials in the aircraft Signup and view all the answers

How do potentiometers in a remote compass compensation system work?

They inject very small DC currents into the flux detector coils Signup and view all the answers

What is a cause for performing a compass adjustment?

After a lightning strike Signup and view all the answers

What do variable potentiometers correspond to in a compass compensation system?

The deviations on east/west and north/south headings Signup and view all the answers

Which of the following accurately describes the process of compass compensation for direct reading compasses?

It is corrected during a compass swing Signup and view all the answers

What occurs during the compass swinging process?

Detection of magnetic influences for correction Signup and view all the answers

Which component is specifically part of the electronic compass compensator?

Variable potentiometers connected to windings Signup and view all the answers

What is performed to correct magnetic deviations detected during a compass swing?

Injection of small DC currents into the flux detector Signup and view all the answers

What is coefcient B error primarily affecting?

East-west headings Signup and view all the answers

Which compensator magnets are adjusted to correct coefcient B error?

Lateral axis magnets Signup and view all the answers

What does coefcient C refer to?

Deviation caused by an imaginary magnet along the wingspan Signup and view all the answers

When flying east or west, what effect does lateral magnetism have?

It strengthens or weakens the magnetic meridian Signup and view all the answers

What type of headings does coefcient C error affect the most?

North-south headings Signup and view all the answers

What is the first step after completing the compass compensation process?

Calibrate the compass Signup and view all the answers

How does fuselage magnetism affect magnetic meridian during north-south flight?

It distorts the magnetic field Signup and view all the answers

What must be recorded after calibrating the compass?

Residual deviations on a calibration card Signup and view all the answers

Study Notes

Instrument Systems Compasses

Direct-reading compasses are essential for displaying an aircraft's heading relative to Earth's magnetic flux and serve as primary heading references in light aircraft.
Remote-reading compasses act as backup references in aircraft utilizing advanced radio navigational aids.
Aircraft magnetism can interfere with compass accuracy, primarily affecting readings during east-west flying due to fuselage magnetism (coef B error) and north-south flying due to wing magnetism (coef C error).

Magnetic Principles

Earth's magnetic field consists of a horizontal and vertical component, with only the horizontal component being relevant for magnetic heading determination.
The magnetic north pole in the northern hemisphere behaves like a magnetic south pole leading to alignment with the Earth’s magnetic field.
Compass errors arise from aircraft's magnetism impacting compass readings, necessitating adjustment through compensator magnets positioned along lateral and longitudinal axes.

Compass Compensation and Calibration

Compass compensation is necessary under various circumstances, including suspected inaccuracies, regular maintenance checks, after major repairs, and following aircraft modifications.
Methods for compass calibration include the comparison method, electronic compass calibrators, and datum compasses.
A compass calibration proforma aids in documenting residual deviations after the compensation process.

Compass Swing Precautions

Compass swings should be conducted in areas devoid of unusual magnetic influences, away from buildings, electronic devices, and other metal objects.
Proper aircraft preparation is crucial, ensuring all equipment is stowed correctly to avoid influencing compass readings.
Non-magnetic tools must be used for adjustments, and completed calibration should be verified to maintain accuracy.

Compass Check Swing Procedure

A check swing is performed at cardinal points to assess compass serviceability and accuracy against previous records without fully recalibrating.

Angle of Attack Indication

The angle of attack (AoA) is critical for lift generation, defined as the angle between the aerofoil's chord line and relative wind direction.
Lift increases with AoA until maximum lift (CL Max) is reached, typically between 12° and 18°, after which stalling occurs.
Stall conditions are independent of airspeed, weight, or flight attitude, meaning an aircraft can stall at any configuration if the critical AoA is exceeded.

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Description

Explore the essential concepts of direct-reading and remote-reading compasses used in aircraft navigation. Understand how Earth's magnetic field influences compass accuracy and the common errors that arise from aircraft magnetism. This quiz will help solidify your knowledge of aircraft navigation tools and their operational principles.