789 Lt R Hampton Gray VC Squadron Ground School (2014)

789 Lt R Hampton Gray VC Squadron Ground School (2014)
Module Seven: Air Navigation

789 Lt. R Hampton Gray VC Squadron Ground School 2014
In This Module: 7.1 Latitude and Longitude 7.2 The Earth’s Magnetism 7.3 Units of Distance and Speed 7.4 Aeronautical Charts 7.5 Navigation Problems 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Types of Air Navigation
Pilotage: Navigation by reference only to landmarks. Dead Reckoning: Navigation by use of predetermined vectors of wind and true airspeed, and pre-calculated heading, groundspeed, and time of arrival. Radio Navigation: Navigation by use of radio aids, either using signals broadcast from ground stations, or satellites. Inertial Navigation: Navigation by self-contained airborn gyroscopic equipment or electronic computers that provide a continuous display of position. Satellite Navigation: Navigation by use of positioning and guidance systems using transmitters and receivers that provide pinpoint positioning accuracy via orbiting satellites. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

7.1: Latitude and Longitude

Latitude and Longitude
Graticule: geometrical pattern of intersecting circles dividing up the surface of the earth. Meridians of Longitude: semi-great circles running north/south, joining the true polls. Parallels of Latitude: circles running east/west parallel to the equator. Equator: Great circle lying equidistant from the polls and considered 0° latitude. Prime Meridian: Meridian running through Greenwich, England at 0° longitude. International Dateline: Opposite side of prime median. 180° longitude. ° = degree ‘ = minute “ = second 1° = 60’ 1’ = 60” 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Geographical Co-ordinates
789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check Describe parallels of latitude. Describe meridians of longitude. What are the equator and prime meridian? How are geographical co-ordinates given? 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Great Circles and Rhumb Lines
A circle bisecting the earth into two halves. Only one great circle can be drawn between two places not diametrically opposite each other. The path along a great circle represents the shortest distance between two points. Rhumb Line: A curved line along the earth’s surface that meets all meridians at the same angle. Only represents the shortest distance if it is directly along the equator or a meridian of longitude. Follows the same heading constantly. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Heading and Bearing 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check What is a great circle? What is a rhumb line? Describe the difference between heading and bearing. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

7.2: The Earth’s Magnetism

Earth’s Magnetism The earth’s magnetic field flows from magnetic pole to pole and surrounds the planet. The lines of magnetism connecting the magnetic poles are called magnetic meridians. A compass’ needle will lie along one of these magnetic meridians, and its north end will seek the north magnetic pole. Magnetic dip occurs near the poles because the field lines are oriented vertically instead of horizontally, pulling the compass needle downwards. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Variation The magnetic poles are not stationary, and as such, do not coincide with geographical poles. The difference in angle between the magnetic meridians and the geographic meridians is called magnetic variation. Because the polls are in motion, the change in variation from year to year is called annual change. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check Where along the earth’s surface is a compass most reliable and why? Where does magnetic dip occur and why? What is magnetic variation? 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Isogonic Lines Isogonic lines or isogonals are lines joining areas of magnetic variation on maps and charts. They are not straight lines, they curve and move, but on aviation charts they will often appear straight. They are represented on aviation charts by dashed lines and the number of degrees of variation. Lines of zero variation are called agonic lines. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Effects of Variation M T Because magnetic heading and true heading are normally not the same, and airplane wishing to fly a true heading of 0° (True North), will fly off course if it follows a compass heading 0° magnetic. As a result, pilots must know how to account for and correct for magnetic variation to ensure that the compass headings they choose actually put them on the true course they wish to fly. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Conversion Between True and Magnetic Headings
To Convert Magnetic to True: Subtract Westerly Variation from Magnetic Heading Add Easterly Variation to Magnetic Heading To Convert True to Magnetic: Add Westerly Variation to True Heading Subtract Easterly Variation from True Heading Variation West, Magnetic Best (More Than True) Variation East, Magnetic Least (Less Than True) 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check What are isogonic lines? What effect does magnetic variation have on flight? When converting from magnetic to true, do you add or subtract westerly variation? When converting from true to magnetic, do you add or subtract easterly variation? 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Compass Errors Deviation Magnetic Dip Northerly Turning Error Acceleration and Deceleration Error 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Deviation When the compass is mounted in the airplane, the metal and radios interfere with the magnetic fields, causing the compass to read incorrectly. The angle between the erred compass heading and the actual magnetic heading is called deviation. Compasses are regularly “swung” to minimize deviation. Any remaining deviation is provided on a compass deviation card mounted inside the airplane. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Magnetic Dip Magnetic dip occurs most strongly near the poles because the field lines are oriented vertically instead of horizontally, pulling the compass needle downwards. This makes compasses inaccurate at latitudes close to the poles (such as in Northern Domestic Airspace), which is why magnetic bearings and headings are not used in these high latitudes. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check Describe compass deviation. As a pilot, how is compass deviation dealt with in the cockpit? How does magnetic dip affect navigation? 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Northerly Turning Error
On turns from the north, northerly turning error causes the compass to lag. On turns from the south, northerly turning error causes the compass to lead. This is caused by magnetic dip as the Z-force is allowed to act on the compass in a banked turn. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Acceleration and Deceleration Error
On east-west headings, acceleration causes the compass to register a turn towards the north. On east-west headings, deceleration causes the compass to register a turn towards the south. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check What does northerly turning error cause the compass to do on turns from the north? From the south? On east-west heading, which way will acceleration cause the compass to register a turn towards? Decleration? 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Dry Vertical Card Compass
The dry vertical card compass looks like a heading indicator but is actually a vertically oriented compass. These compasses do not have a needle floating in liquid and are heavily damped so that they are much less susceptible to magnetic dip, northerly turning error, and acceleration/deceleration error. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

7.3: Units of Speed and Distance

Speed Conversions Knots to MPH = Multiply by 1.15 MPH to Knots = Divide by 1.15 Knots to KM/H = Multiply by 1.85 KM/H to Knots = Divide by 1.85 KM/H to MPH = Multiply by 0.62 MPH to KM/H = Divide by 0.62 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Time Conversions Minutes to Hours = Divide by 60 Ex. 30 minutes / 60 = 0.5 hours Hours to Minutes = Multiple by 60 Ex. 1.5 hours x 60 = 90 minutes Time in Flight = Distance / Groundspeed Ex. Distance = 120 n.m., Groundspeed = 80 kts Time in Flight = 120 / 80 = 1.5 hours 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Distance Conversions 66 nautical miles = 76 statute miles Distance Flown = Groundspeed x Time Flown Ex. Groundspeed = 80 kts, Time Flown = 2 Hrs 80 x 2 = 160 NM Groundspeed = Distance Flown / Time Flown Ex. Distance Flown = 140 Nm, Time Flown = 2 Hrs 140 / 2 = 70 Kts 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check If groundspeed is 80 knots, and the airplane has been flying for 1.5 hours, how far has it flown? If an airplane has been in the air for 15 minutes, and has covered a distance along the ground of 30 nautical miles, what is its groundspeed? If an airplane is flying at a groundspeed of 90 knots and has covered 150 nautical miles, how long has it been in flight for? 789 Lt. R Hampton Gray VC Squadron Ground School 2014

7.4: Aeronautical Charts

Map Making Because the earth is a sphere, it can not be accurately represented on a flat plane. There will always be some distortion. The four basic elements in map construction are: Areas Shapes Bearings Distances Based on the purpose of the map, one or more of these will be preserved as much as possible. This is done by using projections. There are two main types of projections used in air navigational charts; the Lambert Conformal Conic Projection, and the Transverse Mercator Projection. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Lambert Conformal Conic Projection
Meridians are subtle curves or straight lines that converging towards the nearer pole. Parallels of latitude are curved lines concave to the nearer pole. The scale of distance is practically uniform throughout the entire map sheet. A straight line drawn between two points may be assumed to represent an arc or a great circle. VFR Navigational Charts (VNC) and World Aeronautical Charts (WAC) are based on this projection type. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check On a Lambert conformal conical projection, what does a straight line drawn between two points represent? What kinds of charts use Lambert conformal conical projections? Does this type of projection have uniform scale throughout the map? 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Mercator Projection Based on a cylinder instead of a cone. Meridians are straight and parallel lines that do not converge. Parallels of latitude are straight and parallel lines that do not curve. A straight line drawn between any two points will represent a rhumb line. There is no constant scale of distance, and areas are greatly exaggerated at high latitudes. The longitudinal scale must never be used for measuring distance. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Mercator Distortion 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Transverse Mercator Rotates the cylinder so that a meridian of longitude is the tangent instead of a parallel of latitude. Chart is now very accurate along the selected meridian Very accurate in depicting scale, especially over small geographical areas. Can be done for any meridian of longitude 360 degrees around the earth. VFR Terminal Area Charts (VTA) are based on this type of projection. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check Whereas a Lambert conformal conical projection uses a cone, what type of geometrical object does a Mercator projection use? What does a straight line drawn between two points on a Mercator projection map represent? What problem with a Mercator projection does a Transverse Mercator projection solve? What type of chart uses Transverse Mercator projection? 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Types of Aeronautical Charts
VFR Navigational Chart (VNC): Primarily designed for visual navigation. Most useful for flight at lower altitudes and slower speeds. Each chart covers a relatively large area. Charts are named for the principal landmark (I.e. Toronto, Vancouver, etc). Chart scale is 1:500,000 or roughly one inch:eight miles. VFR Terminal Area Charts (VTA): Large scale charts with 1:250,000 scale. Published for airports with high volume of traffic and a mix of controlled airspace. Depict VFR call-up points outside the area and checkpoints within the area. Radio communication information is given on the chart. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Types of Aeronautical Charts
In FTGU, read about: World Aeronautical Charts Enroute Charts Airport/Facility Directory Water Aerodrome Supplement 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Canada Flight Supplement
Shows info on Canadian and North Atlantic aerodromes which are shown on IFR enroute charts, VTA charts, VNC charts, and WAC charts. Should be carried by any pilot departing on a flight. Revised every 56 days. Made up of 6 sections: General Aerodrome and Facility Directory Planning Radio Navigation and Communication Military Flight Data and Procedures Emergency 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check Describe a VNC chart. Describe a VTA chart. What are the 6 sections of the Canada Flight Supplement? 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Chart Information All airway courses are shown in degrees MAGNETIC unless otherwise labelled “T” for degrees true. Aeronautical charts published exclusively for navigation using GPS will have all courses shown in degrees true. Aeronautical charts are built up using three layers: Natural, Cultural, and Aeronautical. A map becomes a chart when navigational information is added. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Scale The scale of the chart is the relationship between a unit of distance on the chart and a unit of distance on the ground. VNC charts have a scale of 1:500,000 (one inch on the chart = 500,000 inches on the ground). A graduated scale line is printed on the border of the chart and gives scale in kilometres, statute miles, and nautical miles. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Latitude and Longitude
On your VNC chart, meridians of longitude and parallels of latitude are marked in 30’ intervals, with 1’ divisions between them. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Relief Layer Tinting: The chart is coloured to represent different levels of elevation. The colour scale is included in the VNC legend. Contour Lines: Contour lines are drawn joining points of equal elevation. The distance between the contour lines indicated slope. Spot Heights: Spot heights show the height at a specific point on the map using a dot and a height listed with it. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check What are the three units of measure Canadian charts provide on the graduated scale? In what increments are latitude and longitude marked on your VNC chart? What are the three main ways relief is shown on a chart? On your VNC chart, what is the approximate latitude and longitude of Pearson International Airport? 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Chart Features Cont’d Isogonic Lines: Lines joining areas of equal magnetic variation are represented by dashed lines. The variation is listed in regular intervals along the line. Communities, Roads and Railways: Towns and small villages = yellow squares. Hamlets = small circles. A city = a yellow shape outlined in black that represents the actual shape and size of the community. Highways = red or brown lines, and double lane highways by double lines. Railways = black lines. Class F Airspace: Class F airspace is depicted outlined with coded information about them on the chart. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Chart Features Cont’d Aerodromes: Small aerodromes are represented by circles with a code indicating status. Hard surface runways are depicted at their location with a diagram of the landing area. Airport information is given in a box adjacent to the schematic depiction of the runway. Compass Rose: A circle overprinted on the chart divided into 360°. The centre of the compass rose is over a transmitting navigational aide, i.e. a VOR or TACAN station. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Aeronautical Information
All VNC charts include a legend that details aeronautical information including: Aerodromes Radio Aids to Navigation Airspace Information Miscellaneous information (i.e. Obstructions, lighting, transmission lines, etc. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check What do isogonic lines join? What does a yellow square on a map represent? A jagged yellow area outlined in black? How are aerodromes with hard surfaces represented on a chart? 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Plotting Instruments Aviation Protractor (Douglas Protractor): Square protractor with a compass rose graduated around the edges in 360 degrees. Transparent with hole in centre so it can be easily placed over markings and landmarks and the chart is visible throughout. ICAO Chart Ruler: Scale ruler with one side in statue miles and one side in nautical miles. Inner scale is for WAC charts, outer scale is for VNC charts. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Use of Douglas Protractor
This gives you TRUE track, which must then be converted to MAGNETIC track using variation. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check Describe the ICAO chart ruler. Describe the Douglas Protractor. How is the direction of a track found using a Douglas Protractor? 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Preparing a Chart for Flight
Draw a straight line on your chart connecting your point of departure and point of destination. Using your Douglas Protractor, determine the direction of the track in degrees true. Apply magnetic variation. For flights up to 300 miles, use average variation by selecting the isogonic line that most closely intersects the centre point of the track. Measure the track using the ICAO ruler and divide it into equal intervals of miles each to allow for quick estimations during flight. Identify landmarks, select a safe flight altitude, and ensure the track is not through restricted airspace. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check On your Toronto VNC, perform the five steps described for a course between Pearson International Airport (CYYZ) and Hamilton (CYHM). Draw a dark black line connecting the two airports. Determine the true track of the course using your Douglas Protractor. Adjust for magnetic variation and get magnetic track. Measure the track in both SM and NM. Identify any significant landmarks or information from the chart along the course. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Ten Degree Drift Lines 10° Airplanes flying along a predetermined course along the ground may be pushed off course by wind. 10 degree drift lines allow the pilot to estimate the angle of deviations from course and to determine the correct adjustment of course necessary to return to the correct track. 10 degree drift lines should always be differentiated from the main course track line (lighter line or different colour). 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Ten Degree Drift Lines - Terms
B C, D E A Required Track: The proposed track of the airplane along the ground. Track Made Good: The actual path of the airplane over ground. Track Error: The angle between the required track and track made good in degrees right or left. Opening Angle: The angle between the required track and track made good. Closing Angle: The angle between the old required track and the new required track needed to get to the destination. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check What is the purpose of 10 degree drift lines? How should 10 degree drift lines be differentiated from the main course track? Describe the five main 10 degree drift lines discussed. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Ten Degree Drift Lines B C, D E A If a pilot finds themselves off course, they can choose to either correct back to the original course, or fly a new course all the way to the destination. However, if the pilot has not passed the halfway point of the course, it is best to fly back to the original track. This can be done either using the double track error method, or the visual alteration method. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Double Track Error Method
After departing from point A and flying the proposed 090° course for 11 minutes, the pilot estimates they are 5° off course to the left. To get back on track, the pilot must: 1) Double the track error (5x2 = 10°) and adjust course 10° to the right, to 100° 2) Fly that course for 11 minutes to get back to the original course line. 3) Turn back left 5° to a heading of 95° to maintain the course to the destination. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Visual Alteration Method
If the pilot can identify a landmark that they know lies directly along the planned course, they can readjust visually by: 1) Estimating their drift. Ex. 5° of drift left means that altering course 5° to the right to 095° will compensate for wind and produce the desired track of 090°. 2) Fly the airplane visually to the landmark that they know is directly along the intended course. 3) Once over that landmark, turn the aircraft to the necessary heading identified in step 1. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check Using your Douglas Protractor and ICAO ruler, draw 10 degree drift lines on your VNC chart around the course you just plotted. Describe the double track error method. Describe the visual alteration method. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Return to Point of Departure
In order to determine the correct course to return to point of departure, while factoring in wind correction, a pilot must take the reciprocal of the heading out, and double the wind correction in the opposite direction. Ex. In this case, the heading out to correct for wind drift was 095° to achieve a track along the ground of 090°. To head back to point of departure at point A, a pilot must: 1) Take the reciprocal of the heading out (095°), which is 275°. 2) Apply double the initial wind correction (5°x2 = 10°) in the opposite direction, to get a heading of 265°. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

One in Sixty Rule An error in the track of one degree will cause an error in position of one mile at a distance of 60 miles. One degree track error 60 miles One mile off of original track line 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check Describe the process for a return to departure point. Describe the one in sixty rule. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

7.5: Navigation Problems

Composition of Velocities
Vectors have two components, one a magnitude, and one a direction. The type of vector most common in aviation is velocity. Velocity = Speed and Direction More than one vector can be acting in an object at once. Ex. An airplane flying north at 90 knots and being pushed by an eastward wind at 10 knots. When velocities act along a straight line (same or opposite direction), they can be easily added or subtracted. When velocities act at angles, they can be solved using the triangle of velocities. V2 V1 VR = V1+V2 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Triangle of Velocities
The solution to a navigational wind and drift problem can be represented by a triangle of velocities. One side represents heading and true airspeed of the airplane. One side represents the direction and speed of the wind. One side represents the resultant track and the groundspeed. Knowledge of any four allows the determination of the other two. All units must be alike. I.e. If distances are in NM, speed must be in knots. 1 Arrowhead = Heading of Airplane 2 Arrowheads = Resultant Track 3 Arrowheads = Wind 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check What is a vector? What is the most common vector in aviation? Describe the three sides of the triangle of velocity. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Flight Computer – Wind Side
The wind side of the e6b flight computer in your nav kits is used to quickly solve wind drift problems without the need for the triangle of velocities. 3 Wind Drift / Variation Scale Grommet Drift Lines Speed Lines Compass Rose 1 2 5 4 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Solving a Wind Drift Problem
Problem: An airplane is travelling from Niagara Falls to Toronto Island Airport. The intended true track is 332°. The true airspeed of the airplane is 85 knots. The wind is 280° true at 25 knots. What is the heading to steer to maintain the intended track, and what is the groundspeed? Known: Intended track: 332°T True Airspeed: 85 kts Wind Direction: 280° Wind Speed: 25 knts 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Set the wind direction (280°) on the compass rose opposite the true index. Move the slide so that any convenient number shows under the grommet. Draw a line straight up 25 units to represent the wind speed, and make an arrow head at the top. Set the intended true track (332°) on the compass rose opposite true index. Set the arrowhead on the wind line to the 85 knot speed line (the true speed of the airplane). Read the groundspeed at the grommet. It should be 67 knots. Follow the arrowhead to the drift lines to determine the wind correction. It should be 13° to the left. Subtract 13° from the intended track of 332° to get the correct heading to steer, OR go to 13° left on the wind correction scale and then read the compass rose at this point. Either way, it should be 319° T. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Wind Drift Problem #2 Problem: The airplane flying to Toronto Island must get there in a given time. I.e., it must realize a certain ground speed. The true track is 332° true. The wind is 060° true at 20 knots. The required groundspeed is 80 kts. What is the heading to steer and the true airspeed that must be flown? Known: Intended track: 332°T Ground Speed: 80 kts Wind Direction: 060° Wind Speed: 20 knts 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Set the wind direction (060°) on the compass rose opposite the true index. Move the slide so that any convenient number shows under the grommet. Draw a line straight up 20 units to represent the wind speed, and make an arrow head at the top. Set the intended true track (332°) on the compass rose opposite true index. Set the grommet over 80 knts (the ground speed needed). Read the true airspeed at the arrowhead. It should be on the 82 knots speed line. Read the wind correction angle at the arrowhead. It should be at the 14° right drift line. Add 14° to the intended true track to get the heading to fly, OR go to the 14° right mark on the wind correction scale and read the corresponding mark on the compass rose. It should be 346° T. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check Complete the wind drift and groundspeed problems on the handout provided. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Flight Computer – Circular Slide Rule
Outer Scale: Represents miles, gallons, true airspeed, and corrected altitude. Inner Scale: Time in minutes, calibrated airspeed, and calibrated altitude. Time Scale: Represents time in hours and minutes. The figures on a slide rule can represent any multiple of 10. Ex. 45 on the inner scale may represent 4.5, 45, 450. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Time, Speed, and Distance
Speed is represented on the circular slide rule by setting the number on the distance scale (outer) opposite the black 60 on the inner scale. When doing speed/distance/time calculations, as long as two are known, the third can be solved by setting the known two and reading the third. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Time, Speed, Distance Problem: The airplane has a groundspeed of 70 knots, and has been flying for 45 minutes. What distance has it flown? Set 70 on the outer scale opposite the black 60 arrow on the inner scale. On the inner scale, find 45 (the minutes flown). Read the number on the outer scale opposite 45 on the inner scale to find the distance flown. Answer: 52.5 nautical miles. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Time, Speed, Distance Problem: The airplane has a groundspeed of 130 knots, and has flown a distance of 200 nautical miles. How much time has elapsed? Set 13 on the outer scale opposite the black 60 arrow on the inner scale. On the outer scale, find 20 (representing 200nm flown). Read the number on the inner scale opposite 20 on the inner scale to find the elapsed time. Answer: 93 minutes or 1 hr 33 minutes. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Time, Speed, Distance Problem: The airplane has has flown 150 nautical miles in 70 minutes. What is its groundspeed? Set 70 on the inner scale (representing time) opposite 15 on the outer scale (representing distance). Find the black 60 arrow, and read the number opposite on the outer scale to find the speed in knots. Answer: 128 knots. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check Complete the time/speed/distance problems on the handout provided. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Fuel Consumption Problem: An airplane is consuming fuel at a rate of 22 gallons per hour. It has 70 gallons of fuel on board. What is its endurance (how long can it fly for?) Set 22 on the outer scale opposite the black 60 arrow. Find 70 on the outer scale (representing gallons). Read the number on the inner scale opposite 70 on the outer scale to get endurance time. Answer: 190 minutes or 1 hour 10 minutes. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Fuel Consumption Problem: An airplane has flown for 45 minutes, and in that time has consumed 16 gallons of fuel. What is its rate of fuel consumption? Set 45 on the inner scale (representing time in minutes) opposite 16 on the outer scale (representing gallons). Find the black 60 arrow on the inner scale and read the number opposite on the outer scale to find fuel consumption rate. Answer: 21.4 gallons/hr. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Conversions Ex. Converting between NM and SM: Place any number under the arrow for either NM or SM, and read the number below the opposite arrow to get the conversion. Ex. Converting between Imp. Gallons and U.S. Gallons: Set any number opposite the arrow for either U.S. or Imperial gallons, read the number opposite the other for the conversion. Problem: How many U.S. gallons is 40 litres? (Hint: a gallon is bigger than a litre). 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Airspeed Correction Problem: Pressure altitude is 16,000’. Outside air temperature is -10°C. Calibrated airspeed is 200 knots. What is true airspeed? In the right hand window, set pressure altitude opposite outside air temperature. Find the calibrated airspeed on the inner scale Read the number opposite on the outer scale to obtain TAS. Answer: 260 knots TAS 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Density Altitude Density altitude is pressure altitude corrected for temperature. Problem: Pressure altitude is 6,000’. Air temperature is 20°C. What is the density altitude?? In the right hand window, set pressure altitude opposite outside air temperature. Read the density altitude in the small window marked ‘density altitude’. Answer: 8000 feet. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Concept Check Complete the fuel consumption, conversions, airspeed corrections, and density altitude correction questions on the handout provided. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

Calculating Climb/Descent Time
When calculating the time of a cross-country flight, there are two ways to factor in the time it takes to climb to altitude and to descend for landing. Calculate takeoff, cruise, and landing as three separate legs and then add the times together. 2) Calculate en route time at altitude for the entire distance and then add one minute for each thousand feet. 789 Lt. R Hampton Gray VC Squadron Ground School 2014

End of Module 7 789 Lt. R Hampton Gray VC Squadron Ground School 2014

789 Lt R Hampton Gray VC Squadron Ground School (2014)

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