Navigation Flashcards
What are the meridians of longitude? How are they measured?
Lines joining the true (geographic) poles of the earth. They are measured from 0° - 180° east and west of the prime meridian in degrees (°) and seconds (‘)
Where is the prime meridian located?
Greenwhich, England
How many minutes are in a degree? How many seconds are in a minute?
There are 60 minutes in a degree and 60 seconds in a minute
How is latitude measured?
Measured 0° to 90° north and south of the equator
Define rhumb line. What are some examples of rhumb lines?
A curved line on the earth’s surface which cuts all meridians at the same angle. All parallels of latitude are rhumb lines, as well as meridians, the equator, and great circles
Define great circle
A circle on the earth’s surface whose plane passes through the center of the globe and divides it exactly in half
Define small circle
A circle on the earth’s surface that does not pass through the center of the globe
What kind of circles are meridians and the equator?
Semi and complete great circle, respectively
Define isogonal lines. How are they numbered and represented on charts?
Lines (not straight) drawn on the map which join areas of equal variation. They are numbered east and west and represented on charts by dashed lines.
What are agonic lines?
Places on the earth where the true and magnetic north are aligned
What are the characteristics of the mercator projection?
Meridians are straight and parallel lines
Parallels of latitude are straight and parallel lines
A straight line drawn between any two points on the chart will represent a rhumb line
No constant scale of distance
Areas are greatly exaggerated in high altitudes
What kind of projection is this?
Mercator
What projection is this?
Transverse mercator
Describe the characteristics of the transverse mercator projection
Point of Tangency is a meridian of longitude rather than the equator
Chart is more accurate along the selected meridian
Accurate in depicting scale, especially on charts covering a relatively small geographical area
Any of the 360 meridians of longitude can be selected as the point of tangency for the chart projection
Describe the characterstics of the lambert conformal projection
Meridians are curves or straight lines converging towards the poles
Parallels of latitude are curves which concave towards the nearest pole
The scale of distance is uniform throughout
A straight line drawn between two points can be assumed to be a great circle
What kind of projection is this?
Lambert conformal
Which projection is used by VNC? What is the scale?
Lambert conformal conic
1:500,000
Describe the difference between a chart and a map
Chart: represantation in miniature and on a flat surface, a portion of the earth’s surface. emphasis is places on conformity of topography and geographical features
Map: geared towards item of interest. low conformal accuracy
What projection is used for VTAs? What is the scale?
Tramsverse mercator
1:250,000
Describe low enroute charts (LO)
Provide information for radio navigation over designated airway systems
Up to 18,000 feet
Do not portray cities or topographical features; only navigation aids, airways, and communication frequences
Scale is not constant & dependent on chart
Describe the 24 hour system in longitude
What is 12:00 (noon) UTC in NST, AST, EST, CST, MST, and PST?
If Greenwhich is 160° W of your position, how do you calculate the LCT of your position?
Add 10 hours 40 minutes (160 x 4 = 640mins) to GMT
If Greenwhich is 72° of your position, how do you calculate your LCT?
Subtract 4 hours 48 minutes (72 x 4 = 288mins) from GMT
Define indicated airspeed and true airspeed
Indicated airspeed: the airplane’s speed as indicated by the airspeed indicator
True airspeed: speed of the airplane relative to the air. calibrated for density and temperature
Define groundspeed
Speed of the airplane relative to the ground
Define heading and track (intended)
Heading: the angle between the longitudinal axis of an airplane at any moment and a meridian
Track (intended): the direction an airplane intends to travel over the ground
Define track made good
The actual path traveled by the airplane over the ground
Define drift
Wind blowing from either side of an airplane will cause the airplane to drift away from its intended track
Describe heading, TAS, track, GS, windspeed, and direction using the triangle of velocity
When is a GFA issued? When it is valid?
00Z, 06Z, 12Z, 18Z at 30 minutes before period. Valid 12 hours with IFR outlook for next 12 hours
What does a GFA show? To what height are cloud heights reported?
Shows a general statement of weather conditions to be expected over a particular region. Cloud heights are reported up to 24,000 feet ASL
When are TAFs issued? When are they valid?
Issued for 06Z, 12Z, 18Z, and 00Z (08Z, 14Z, 20Z and 02Z) at 20 minutes before each period. Valid 12 or 24 hours
What does the TAF show?
Weather expected to affect landing and take off at the aerodrome. Reports wind, low level wind shear, prevailing visibility, significant weather, and sky conditions for area within 5 nm
What information can be reported in a METAR or SPECI?
Wind gusts and visibility, present weather, obscured sky, dewpoint setting, recent weather, runway visual range, sky condition, temperature, wind shear
What does the Upper Winds and Temperature (FD) report and how often?
Estimate of upper wind conditions and temperatures at 3000 foot intervals. Observations are taken at 00Z and 12Z
Which report is the best source for calculations of GS, Hdg, CAS, DA, etc?
Upper Winds and Temperature
Describe the cruising altitudes in Southern Domestic Airspace
What do the three different scales on the E6B calculator indicate?
Outer (A) scale: distance, gallons, true airspeed
Middle (B) scale: time, calibrated airspeed, pressure altitude, speed index
Inner (C) scale: time in hours
Without using a E6B, what is the density altitude at Ottawa? A30.02”, temp=39°
2874’
What does the airspeed correction table show?
Explain how to calculate your ETA
Choose an engine speed
Find corresponding true airspeed
Convert to groundspeed taking wind into account
Calculate time require to fly the distance of the leg
What is considered when calculating the fuel required for a flight?
Time enroute, fuel rate at chosen RPM, fuel burn over the time enroute
At what percentage power is normal cruising done?
65% - 75% power
How is RPM chosen?
Fly a constant % of horsepower with a constant fuel burn
The power setting (RPM) to maintain this % of HP will change with altitude
Conversely, we can elect to fly a constant RPM, and the fuel burn will change with altitude
Define deduced (dead) reckoning
Vector navigation using wind, true airspeed, heading, groundspeed, and ETA
Define pilotage
Navigation by reference to landmarks only
Define radio navigation and celestial navigation
Radio navigation: navigation by radio aids (triangulation of timed signs)
Celestial navigation: navigation by measuring angles to heavenly bodies to determine position on the earth
Define air position and ground position
Air position: Imaginary position of an aircraft assuming that there has been no wind since it left the ground. calculated by navigators using only heading and airspeed for approximate position
Ground position: Actual position of an aircraft over the ground (when winds are accounted for)
Define track error
Angle between the required track and the track made good, left or right of required
Define opening angle and closing angle
Opening angle: angle between required track and TMG
Closing angle: angle between the old required track and the new required track necessary to arrive at the destination
Define bearing
Angle between the object seen by the observer and the observers meridian
Define true heading, magnetic heading, and compass heading
True heading: heading that allows for drift from wind
Magnetic heading: allows for variation
Compass heading: allows for deviation
What is the difference between magnetic and geographic poles?
Geographic poles are the axis upon which the earth rotates. Magnetic north is where there is the most magnetic attraction from ferrous materials in the earth’s crust. Maps use the true (geographic) north while the compass points towards the magnetic north
What is variation?
The angle between magnetic north and true north (changes annually)
Define deviation
Angle that the compass needle is deflected from the magnetic meridians which is caused by magnetic disturbances in the aircraft
Where is the compass correction card found?
In the journey log and in aircraft near the magnetic compass
What factors affect choice of route?
Terrain
Fuel availability and requirements
CYR, CYA, CYD areas
Flight over water
Weather
Where should check points be set?
At equal distances. The first one should be a fix/landmark and all points should be geographically recognized
What allows a pilot to estimate track errors and make corrections to regain desired track?
Drawing 10° drift lines
How can position lines be used to obtain a fix?
Use two or more locations that are visible on the ground and map. Find their bearing in relation to you and draw a straight line from the landmark. The point at which the two tracks meet is your estimated location
When is the double track error method used?
Only before you get to your 1/2 waypoint
Explain how to use the double track error method
Explain how to use the sum of opening and closing angles
Find how many degrees off track you are in relation to your departure (opening angle)
Find how many degrees off track you are in relation to your destination (closing angle)
Add the two angles together
Gives correction angle direct to destination
May be used at any point along your route
What is the 1 in 60 rule?
Every 1°change equals 1NM after 60NM from the station
When is the two point visual method used?
When wind is not known
How is the two point method used? When it is useful?
Pick two points (visual references) on track
The heading flwon by the pilot between those two points will determine the heading (wind component) for the rest of the leg
This method is useful on diversions
Briefly describe 7 elements of pre flight preparation
Map folding - Ready before flight.
Documents - Needed & Legal
Latest Wx - Go No Go & Change to Plan
Fuel - Safe, Legal, & Available (later better)
Weight & Balance - Safe & Legal (last)
Aircraft Serviceability -Journey log checks
Filing a Flight Plan/Itinerary - On the Clock
What map prep (folding and orienting) should be done pre flight?
Route, drift lines, selection of checkpoints
Where can an aircraft’s weight and balance be found?
Within envelope found in POH at all times
In the Aircraft Weight and Balance Report
When are flight plans or flight itineraries required to be filed?
If a flight goes outside 25nm from point of departure, when going to or from a military aerodrome, or when going on transborder flight
How are flight plans/itineraries filed?
With FSS by telephone, online, or air filing by radio
What are some things to remember for cockpit organization?
Fold map with X-C marks displayed ahead of time
Use a knee board
Bring an E6B, pencils, cash/credit card for fuel etc
Bring extra oil and funnel
Current Canada Flight Supplement
Get Compass Headings from the Compass Correction Card
Bring the Journey Log Book
Dress properly for the season (Winter, Summer)
What logistics should be taken care of on departure?
Record time wheels up
Open flight plan
Head to set heading point as soon as able
What are the 5 T’s when approaching SHP?
Time, twist, turn, track, throttle (and sometimes talk)
What frequencies should be monitored in flight?
- 5 if dual comm equipped
- 7 even when receiving flight following
What are 4 course correction methods?
Double track error, opening/closing angle, 1:60 rule, visual alteration
What logistics should be taken care of on arrival?
Call ahead of control zone (10-20nm depending on size and class of airspace)
Plan descent and approach according to traffic procedures or ATC instructions
Close flight plan
What are 6 in flight procedures?
Map reading, orientation, anticipation, confirmation, pin-pointing, watching map to ground
What are some reasons to divert to an alternate destination?
Bad weather, fuel shortage, sickness, minor aircraft malfunction
What should be done after deciding to divert?
Pin point position of aircraft on the map
Determine track/heading or use geographical landmarks to alternate destination
Set heading indicator
Take time (ETA/ETE, revised ETA)
Departure angle (two point visual method)
What should you calculate when returning to departure point?
Reciprocal heading and double wind correction angle the opposite way
Why is it more important to know where you are at all times when flying low?
Map reading becomes more difficult at lower altitudes
What procedures can be done when lost?
Triangular pattern (2 min. legs 120° turns, turning right with operating radio, turning left with no radio), DF steer or radar vectors
List three types of radio navigation
Automatic Direction Finder (ADF)
Very High Frequency Omnidirectional Range (VOR)
Global Positioning System (GPS)
Define reflection, refraction, diffraction, and attenuation
Reflection: occurs at the surface separating two mediums. The angle of incidence equals the angle of reflection
Refraction: bending of a wave as it passes obliquely from one medium to another
Diffraction: bending which occurs when a wave grazes the edge of a soilid object through which it cannot pass
Attenuation: loss of wave energy as it travels through a medium
Define the following wave characteristics: cycle, wavelength, amplitude, frequency
Cycle: interval between points
Wavelength: linear, metric measurements of a wave
Amplitude: strength or width of a wave
Frequency: cycles per second
Describe the difference in amplitude and frequency between AM and FM
What are the frequency categories (very low to extremely high) and their respective wave lengths?
Depending on the frequency, the radiated signal is most efficiently propagated by only one of the three methods. What are these methods?
Ground waves, sky waves, space waves
What method of signal propagation do VLF, LF, and MF use?
Ground waves and sky waves
What method of signal propagation is used for HF?
Sky waves
How are VHF and UHF frequencies affected by atmospheric conditions?
Path is predictable and not affected by atmospheric conditions
How are SHF and EHF signals affected by atmopsheric conditions?
Some attenuation and scattering can be caused by precipitation and the atmopshere
What is NDB used for?
Provides reception of voice and navigational signals
What frequency do NDBs operate in?
200-415KHz
How does the ADF antenna obtain the strongest signal?
By being rotated mechanically or electromagnetically
Where are the ADF antennae mounted on an aircraft?
In a single blade on the bottom of the fuselage
What errors can be observed when using ADF?
Twilight effect, mountain effect, mountain reflection, shoreline effect, electrical attraction, bank error
When is a bank error present and why?
Bank error is present in all turnsbecause the loop antenna is mounted in line with the longitudinal axis and is shielded from the station during turns
Explain how lighting affects ADF use. What is this error called?
Electrical Attraction error. Radio waves are produced when lightning discharges. These radio waves tend to have a greater power output than those produced by NDB stations
Explain the shorelines refraction error
Shorelines can bend or refract low frequency radio signals as they pass from land to water. Because of this a station outside 30 degrees from shore should be selected
What is the twilight effect? How can it be minimized?
At night sky waves are much stronger than inthe day due to the reflection of the sky waves by the ionosphere. Due to this reflection errors occur in the needle.
Can be minimized by averaging out the fluctuations, flying at a higher altitude or selecting a station with a lower frequency than 350KHz
What is the mountain effect error? How can it be minimized?
Mountain and cliffs can reflect radio waves. Some slopes may have ore deposits that can cause ambiguous indications. Can be minimized by using strong signals not obscured by terrain
List the advantages of NDB
Low cost of installation and of maintenance - smaller airports can have an approach where cost would otherwise be prohibitive
Longer range than higher frequency navigational facilities
Provides navigation signals at lower altitude due to the ground wave
Not restricted to line of sight
Describe the different ADF controls
ON/OFF: turns receiver on/off
ADF: selects only the non-directional antenna, thus disconnecting the bearing selector from the system
BFO: beat frequency oscillator, used for tuning unmodulated signals broadcast by stations in foreign counties
FRQ: flips standby frequency to active
FLT/ET: light timer
SET/RST: standard timer
What is the TIMS procedure for all navigation aids?
Tune
Identify
Monitor
Set
How is relative bearing measured?
From the longitudinal axis of the aircraft to the bearing pointer (clockwise)
What do you get by adding relative bearing and magnetic heading?
Bearing to the station
How will triangulating between two stations help you if you’re lost?
It will pinpoint your location
What will happen if you home to an NDB without correcting for wind?
The ground track will be curved
How do you home to an NDB?
Turn to keep the BP on the nose
What is a RMI?
Radio Magnetic Indicator
ADF information is displayed on a magnetic rotating card. Provides bearing to the station in degrees magnetic
What is the reciprocal (180°) of the aircraft’s magnetic bearing to the station?
Bearing from the station
What is TACAN?
Tactical Air Navigation System: UHF omni-directional navigation aid with DME that is primarily used by the military
What is VORTAC?
A site with a collocated TACAN and VOR. VORTAC information can be received by VOR receivers
How does VOR work? How do you know you are due south of the station?
One light flashes in all directions every minute
One light rotates once a minute
If the second light appears 30 sec after you see the first one, you know you are due south of the station
What is the purpose of the CDI? How is this affected by distance from the station?
CDI indicates how many degrees you are off course
If you are 5 degrees off course close to the station, you may only be a few hundred feet off course
If you are 5 degrees off course 60 miles from the station, you will be 5 miles off course
What are the components of an OBS?
OFF: out of range, over the station, area of ambiguity
TO: area rear of the reference line
FROM: area forward of the reference line
CDI: course deviation indicated
Radial Selector
Where is the VOR reference line located?
The OBS indicated you are right of the 160 radial for VOR with frequency of 110.30. Where are you relative to the station?
Probably just over the station. (neither a TO or a FROM indication, nor a flag)
What effect does aircraft heading have on OBS?
No effect. OBS is position sensitive, not heading sensitive
Describe how to position fix using an OBS
Establish which radial you are on (radials emanate from the system)
Your OBS bar should be centred with a from indication
Whatever is on the top of your OBS is the radial you are on
Describe how to position fix using DME on an OBS
If you know what radial you are on, and how far away from the station, you can get an immediate fix using only one station
How do you track from a station?
Turn to the heading indicated at the top of the OBS. Center the OBS TB with a from indication
How do you maintain course?
The bar represents your desired radial and the centre of the OBS represents your position relative to the radial
Begin with centered CDI. If the bar goes left, correct left, If the bar goes right, correct right
How do you track to a station?
Turn to the heading indicated at the top of the OBS and center the OBS TB with a to indication
Where is the radial located on the OBS when you are flying from and to the station?
From: radial is at the top of the OBS
To: radial is at the bottom of the OBS
How accurate is VOR track alignment?
Maintained within a tolerance of +/- 3°
How are VOR stations identified?
Using morse code
What is the maximum permissible error for VOR - VHF omni test?
+/- 4°
List the errors and disadvantages of VOR
Restricted to line of sight reception
At high altitude it is possible to receive interference from other stations
Site error effect: interference from topographical features in immediate vicinity of the VOR
Terrain error effect: signals can be reflected by terrain, or the shadow of the terrain can mask the signal
Receiver/ground station error: equipment failures
What is scalloping?
Distortion of propagation over uneven terrain
Which VOR error is most serious? What is the error amount?
Ground station error is the most serious, but is seldom in excess of 2° and in no case can it exceed +/- 3°.
How can VOR errors be identified?
Irregular course display, warning flag, and limited distance range
How does the VOT test work?
Tune your VOR to the VOT signal.
Set the course selector to 0 degrees, and the track indicator should be centered.
The TO-FROM indicator should read FROM.
Next, set the course selector to 180 degrees
The TO-FROM indicator should read TO, and the track bar should then be centered.
How does a primary radar work?
Signal is sent and reflected (at the speed of light) by rotating beacon
The signal is reflected off aircraft, ground, moisture, birds, etc
The time it takes for the signal to return can be translated into a distance
How does a secondary radar work?
A specific signal is sent out that interrogates targets
Transponder is the only equipment that sends a response
Mode A: four-digit code is returned
Mode C: four-digit code and altitude is returned
Mode S: all the above plus individual flight plan information
Radar centers employ combination of primary, secondary radar
What do the following transponder codes mean: 1200, 1400, 7500, 7600, 7700
1200: VFR at or below 12 500’
1400: VFR above 12 500’
7500: Aircraft hijacking
7600: “Can’t talk”
7700: “Got an emergency”
What is the purpose of the primary radar in the cockpit? How is the strength of the signal influenced and represented?
Weather radar. The larger the storm, the greater the moisture, and the stronger the return signal. The strengths of signals is represented by various shades of colour on a display
What is the purpose of the secondary radar in the cockpit?
Traffic collision avoidance system (TCAS)
How does GPS work to determine a 3-dimensional position?
GPS receiver receives four signals at a time and translates the time it took each signal to arrive from the satellite into a distance. Triangulates between four satellites to determine a 3-dimensional position
A problem with the GPS system is that a cheap receiver clock can’t accurately compare the time the signal was sent. What is a remedy?
Using four satellites at once
A problem with the GPS system is the geometric dilution of precision. What is a remedy?
Using an expensive, smart receiver that tracks known position of all satellites in sight and uses the satellites that are farthest away
What is the ephemeris error?
Satellite is not where we think it is due to slight deviations in orbit
What is the multipath error in GPS?
Signal is bounced around and reflected - it doesn’t follow a straight path
Name is a remedy to the following GPS errors: ephemeris error, receiver error, multipath error, murky ionoshpere
Differential GPS
Explain how differential GPS works
Station is on the ground at a known position
Monitors the GPS system continuously
If it gets a reading telling it that is not where it knows it is, the error will be tracked and resolved
The area is transmitted to all GPS receivers in the error so they can correct accordingly
Many receivers show no indication that the system is in error. What is a remedy?
Receiver autonomous integrity monitoring (RAIM). Must receive signals from 6 or more satellites to monitor the trustworthiness of the system. Faulty satellites can be dediced and excluded
What is WAAS?
Wide area augmentation system. Covers extensive service area and broadcasts corrections to aircraft via a communications satellite
What is LAAS?
Local area augmentation system. High precision local corrections that are broadcasted on a VHF radio data link. Accurate enough to permit Category III landing
What are advantages of the GPS system?
Gives position information in transoceanic & isolated areas
Curved/detailed arrival paths to airports
Not restricted to airways
Position information broadcasts to ATC
Extreme degree of accuracy (within 10cm on kinetic GPS)
GPS can fail. What should you do to prepare for this?
Maintain basic nav skills
