Geography: Navigation Basics

Questions and Answers

What is the approximate compression of the Earth?

0.3% (correct)

0.03%

1/3000

A Graticule is the name given to:

A series of Latitude and Longitude lines drawn on a chart or map

Both a & b are correct (correct)

A series of lines drawn on a chart

A selection of small circles as you get nearer to either pole

A great circle has its North vertex at 70N 130E. What is the position of its South vertex?

70S 050E (correct)

70N 050E

70N 050W

70S 050W

Given the compression of the Earth is 1/297 and the semi-major axis at the Equator is 6378.4 km, what is the semi-major axis at the Poles?

6356.9 Km Signup and view all the answers

A nautical mile is defined as:

The length of the arc of a great circle which subtends an angle of one minute in the center of the Earth. Signup and view all the answers

You are correctly on the glideslope and passing a height of 1000 feet QFE. What is your range from the touchdown point? (Assume 1 nm = 6000 feet)

4 nm Signup and view all the answers

If an aircraft is 3° off the required track at a range of 120 nm, how far in nautical miles (nm) is the aircraft off the required track?

6 nm Signup and view all the answers

An aircraft leaves point A to fly to point B, 95 nautical miles distance. The aircraft's position is found from a 'pinpoint' 7 nm right of track after flying 35 nm. What is the track error?

14° right Signup and view all the answers

On a chart, 49 nautical miles is represented by 7.0 centimeters. What is the scale?

1/1,296,400 Signup and view all the answers

What type of projection is a normal Mercator chart?

cylindrical Signup and view all the answers

The correct combination of the statements Cylindrical, Perspective, Non-Perspective, Conformal, Conical, Azimuthal:

(i), (iii) and (iv) Signup and view all the answers

A direct Mercator graticule is:

Rectangular Signup and view all the answers

On a normal Mercator chart, rhumb lines are represented as:

Curves convex to the Equator Signup and view all the answers

On a direct Mercator, Great Circles can be represented as:

Straight lines and curves Signup and view all the answers

On a direct Mercator, with the exception of the meridians and the Equator, Great Circles are represented as:

Curves concave to the Nearer Pole Signup and view all the answers

The angle between a straight line on a Mercator chart and the corresponding great circle is:

Earth convergency Signup and view all the answers

When do `equinoxes' occur?

March and September Signup and view all the answers

When it is the Winter Solstice in the Southern Hemisphere, the sun will be overhead?

the Tropic of Capricorn Signup and view all the answers

What is the angle between the Equinoctial and Ecliptic?

23'/20 Signup and view all the answers

The Declination of a celestial body (the Sun) measured on the Celestial Sphere is analogous to which on Earth?

latitude Signup and view all the answers

A sidereal day is?

equal to a real solar day Signup and view all the answers

At a specific location, the value of magnetic variation depends on:

the value of true heading Signup and view all the answers

At the magnetic equator, which of the following is zero?

Variation Signup and view all the answers

The value of magnetic variation on a chart changes with time due to:

movement of the magnetic poles, causing an increase Signup and view all the answers

How is the direct reading magnetic compass made aperiodic?

keeping the magnetic assembly mass close to the pivot point and using damping wires Signup and view all the answers

Match the navigation terms with their definitions:

Convergence, Deviation, Variation = Angle between true north and compass north, Angle between magnetic and true north, Angle between grid north and magnetic north Isogonal, Dip, Drift = Line along which the declination is the same, Angle between a horizontal plane and the magnetic field, Angle between the track made good and a true course Perihelion, Aphelion, Equinox = Point in a planet's orbit that is nearest to the Sun, Point in a planet's orbit that is farthest from the Sun, Time when the plane of the Earth's equator passes through the center of the Sun Signup and view all the answers

The period of validity of an FMS database is:

28 days Signup and view all the answers

In an IRS, what is the relationship between the accelerometers and the platform?

The accelerometers are strapped down but the platform is gyro stabilised Signup and view all the answers

What does the FMC position represent?

Computer generated from the IRS and radio navigation positions Signup and view all the answers

How is magnetic variation information obtained in a Flight Management system (FMS)?

Stored in each IRS memory Signup and view all the answers

When and where are IRS positions typically updated?

Only on the ground during the alignment procedure Signup and view all the answers

For a position in the southern hemisphere, the effect of acceleration errors are greatest on headings:

135°(C) and 315°(C) Signup and view all the answers

An aircraft in the southern hemisphere is turning from a heading of 045 °(C) to 315 °(C) using a DGI. At the end of the turn the compass will read _ than 315 ° and liquid swirl will _ this effect.

more increase Signup and view all the answers

In a standby compass the magnet system is immersed in a transparent liquid. The purpose of this liquid is to:

increase sensitivity at high latitudes, lubricate bearings Signup and view all the answers

To improve the horizontality of a compass, the magnet assembly is suspended from a point:

above the centre of gravity Signup and view all the answers

The magnitude and sense of turning error shown by a direct reading compass varies with:

only 1, 3, 5 and 6 are correct Signup and view all the answers

During a sustained turn the nearer magnetic pole, the effect of liquid swirl will compass turning error.

away from - increase Signup and view all the answers

When carrying out a turn at the magnetic equator there will be:

a tendency to underread turns through south and overread turns through north Signup and view all the answers

What is your true track if the heading is 156°T, TAS is 320 knots, and W/V is 130/45?

160 Signup and view all the answers

If you are heading 345°M with a variation of 20°E and take a radar bearing of 30° left of the nose from an island, what bearing do you plot?

160°T Signup and view all the answers

Given a pressure altitude of FL55, a QNH of 998, and SAT of +30°C, what is the Density Altitude?

7750 feet Signup and view all the answers

Where is convergence on a Transverse Mercator chart correct?

the datum meridian and the Equator Signup and view all the answers

When is the last point at which an INS or IRS may be selected to NAV mode?

Immediately prior to push back or taxy from the gate Signup and view all the answers

On a particular take-off, if you can accept up to 10 knots tailwind, with a QDM of 047, variation of 17°E, and wind direction of 210, what is the maximum wind strength you can accept?

11 knots Signup and view all the answers

What is the agonic line?

is midway between the magnetic North and South poles Signup and view all the answers

On a 12% glide slope with a groundspeed of 540 knots, what is your rate of descent?

6550 feet/min Signup and view all the answers

What does the sensor of an INS/IRS measure?

displacement Signup and view all the answers

At 65 nm from a VOR, descending from FL330 to FL100 with a mean groundspeed of 240 knots, what rate of descent is required?

1630 feet/min Signup and view all the answers

In an Inertial Navigation System, what is the output of the first stage North/South integrator?

latitude Signup and view all the answers

In which month does aphelion occur?

July Signup and view all the answers

What is the highest latitude listed below at which the sun will rise above the horizon and set every day?

66° N Signup and view all the answers

Given a pressure altitude of 29000 feet and SAT of -55°C, what is the density altitude?

26000 feet Signup and view all the answers

From point A to B, a 2368 nautical mile journey with outbound groundspeed of 365 knots, homebound groundspeed of 480 knots, and 8 hours 30 minutes safe endurance, what is the time to the PNR?

290 minutes Signup and view all the answers

What is the UTC time of sunrise in Vancouver, British Columbia, Canada (49N 123 30W) on the 6th December?

2324 UTC Signup and view all the answers

How does scale change on a normal Mercator chart?

Expands as the secant z (2 co-latitude) Signup and view all the answers

If you are on an ILS 3-degree glideslope passing over the runway threshold at 50 feet and your DME range is 25 nm from the threshold, what is your height above the runway threshold elevation?

7450 feet Signup and view all the answers

At 1200 Standard Time in Queensland, Australia on the 10th July, what is the Standard Time in Hawaii, USA?

1600 ST 09 July Signup and view all the answers

Study Notes

Here are the study notes for the text:

Direction, Latitude, and Longitude
- The Earth's compression is approximately 1/297.
- The semi-major axis of the Earth at the equator is 6378.4 km.
- The semi-major axis of the Earth at the poles is 6356.9 km.
- A graticule is a series of lines drawn on a chart, including latitude and longitude lines.
- A great circle is the shortest distance between two points on the Earth's surface.
- A nautical mile is defined as the length of the arc of a great circle which subtends an angle of one minute in the center of the Earth.

Great Circles, Rhumb Lines, and Distances on the Earth

Change of Latitude and Longitude
- Change of latitude is calculated by subtracting the latitude of the initial position from the latitude of the final position.
- Change of longitude is calculated by subtracting the longitude of the initial position from the longitude of the final position.
Rhumb Lines
- A rhumb line is a line that crosses all meridians at the same angle.
- A rhumb line is not a great circle, but it is a line of constant direction.
- The shortest distance between two points on the Earth's surface is along a great circle, not a rhumb line.

Earth Magnetism

Magnetic Variation
- Magnetic variation is the angle between the direction indicated by a compass and magnetic north.
- Magnetic variation changes with time due to the movement of the magnetic poles.
- Isogonals are lines of equal magnetic variation.
Dip Angle
- The dip angle is the angle between the horizontal and the total magnetic force.
- The dip angle is zero at the magnetic equator and 90° at the magnetic poles.

Wind Components

Wind Directions
- The wind direction is measured from the true north.
- The wind direction is given in the TAF (Terminal Aerodrome Forecast) as a 3-digit code (e.g., 310/25).
Headwind and Crosswind Components
- The headwind component is the wind speed component that is directly in line with the aircraft's direction of motion.
- The crosswind component is the wind speed component that is perpendicular to the aircraft's direction of motion.

The 1 in 60 Rule

Track Error
- Track error is the angle between the aircraft's actual track and the required track.
- Track error can be calculated using the 1 in 60 rule.
Correction of Track
- To correct for track error, the aircraft must fly a heading that is equal to the required track plus the track error.

Position Fixing
- The 1 in 60 rule can be used to determine the aircraft's position by measuring the angle between the actual track and the required track.
- The distance off track can be calculated using the 1 in 60 rule.

Other Applications of the 1 in 60 Rule

Glide Slope
- The 1 in 60 rule can be used to calculate the height of the aircraft on a glide slope.
- The rate of descent can be calculated using the 1 in 60 rule.

Topographical Maps and Map Reading

Map Symbols
- Different symbols are used to represent different features on a topographical map.
- The symbol for an unlighted obstacle is a triangle.
- The symbol for a lighted obstruction is a circle.
Map Reading
- The aircraft's position can be determined by using the map to measure the distance and direction from known landmarks.

Convergence and Conversion Angle

Convergence
- Convergence is the angle between the meridians at two different points on the Earth's surface.
- Convergence can be calculated using the formula: convergency = ch.long x sin mean lat.
Conversion Angle
- The conversion angle is the angle between the rhumb line and the great circle.
- The conversion angle can be calculated using the formula: conversion angle = ½ x convergency.### Navigation Fundamentals
The circumference of the Earth is approximately 40,075 km (24,901 nm).
1 nautical mile (nm) is equal to 1,852 meters (6,076.1 feet).
An ICAO nautical mile is defined as 1,852 meters (6,076.1 feet).

Latitude and Longitude

The shortest distance between two points on the surface of the Earth is a great circle route.
Latitude is the angular distance of a point on the Earth's surface from the Equator, measured from -90° to 90°.
Longitude is the angular distance of a point on the Earth's surface from the Prime Meridian, measured from -180° to 180°.

Convergence and Departure

Convergence is the angle between a meridian and a rhumb line at a given latitude.
Departure is the distance between two given meridians, measured along a stated parallel, and expressed in nautical miles.

Mercator Charts

A Mercator chart is a cylindrical conformal map projection.
Rhumb lines are represented as straight lines on a Mercator chart.
Great circles are not represented as straight lines on a Mercator chart.
Scale factor along the meridian is 1, and along the parallels is sec λ.
Convergence between the aircraft's meridian and the meridian of the NDB is important when plotting on a Mercator chart.

Lambert's Conformal Chart

A Lambert's conformal chart is a conical conformal map projection.
Scale on a Lambert's conformal chart varies slightly as a function of latitude and longitude.
Constant of the cone is important in determining the scale of the chart.
The best chart made by Lambert's conformal projection is between the latitudes of 12°S and 74°N (or S).

Ellipticity of the Earth

The value of ellipticity of the Earth is 1/297.
Semi-major axis of the Earth, measured at the axis of the Equator, is approximately 6,378.4 km.
Semi-major axis of the Earth, measured at the axis of the Poles, is approximately 6,356.9 km.

Magnetic Variation

Magnetic variation changes slowly over time.
At the magnetic equator, dip is zero.
Magnetic variation on a chart changes with time due to movement of the magnetic poles.

Aircraft Performance

Pressure altitude is affected by temperature and elevation.
Density altitude is important for aircraft performance.
True airspeed (TAS) is affected by wind and Mach number.

Wind and Drift

Drift is the angle between the aircraft's heading and track.
Wind velocity is important for calculating drift and groundspeed.
Crosswind is an important factor to consider when landing.

Time and Speed

Time to go can be calculated using groundspeed and distance to go.
Course, TAS, and wind velocity are important for calculating true track.

Others

Scale on a chart can be expressed by the representative fraction, plain statement, or graduated scale.
A direct Mercator graticule is rectangular.
On a normal Mercator chart, great circles are not represented as straight lines.
A polar chart is the best between 90° and 74° (either of N or S) and is made by a Gnomonic or Stereographic projection.### Navigation Questions
The text contains 53 navigation questions, ranging from topics such as True Mach Number, track and groundspeed, to INS-equipped aircraft, charts, and time theory.

Question Breakdown

Questions 1-22: Focus on topics such as Mach Number, track and groundspeed, wind velocity, airfield elevation, and navigation charts.
Questions 23-26: Cover time theory, including perihelion, aphelion, equinoxes, and the declination of the sun.
Questions 27-32: Discuss topics like Local Mean Time, Zone Time, and the conversion of longitude to time.
Questions 33-36: Explore gridded charts, including conformal conic charts, polar stereographic charts, and the relationship between grid and true tracks.
Questions 37-41: Delve into the direct indicating compass, including its requirements, acceleration errors, and magnetic deviation.

Key Concepts

True Mach Number (TMN) and its calculation
Track and groundspeed, including the effects of wind velocity
Airfield elevation and its impact on pressure altitude
Navigation charts, including Mercator and Transverse Mercator charts
Time theory, including the Earth's orbit and the declination of the sun
Local Mean Time, Zone Time, and the conversion of longitude to time
Gridded charts, including conformal conic and polar stereographic charts
The direct indicating compass, including its requirements, acceleration errors, and magnetic deviation

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Learn about the fundamentals of navigation, including the Earth's dimensions, latitude and longitude, and units of measurement. Understand the concept of graticules, great circles, and nautical miles.