GNAV Flashcards
The magnetic north
Position varies with time
How to check the pre flight condition of the direct compass compass
Check the general condition and correct heading indication
Find scale for Lambert chart. Given 2 meridian: 10W and 20W. Lat is 56N. Measure on chart is 7cm. Find the scale
1: 9000000
Which line is the parallel of meridian (there’s a diagram of sphere)
B
Polar Stereographic meridians
Radiate away from pole
Apparent solar time caused by
Earth orbits at diff speed around the sun
What is ambient air temp
Ram rise equals to
One option was ambient air temp = SAT
Mercator chart: Chart Convergency equals
Zero
Mercator Chart both lat. and long lines
Straight lines
RMI measured by aircraft from VOR Goose 252T
Longitude and latitude of Goose is 53N60W, Var 32 deg West at VOR, 28deg west at aircraft: calculate bearing from VOR to aircraft to be potted on Lambert chart
From aircraft: 252 (T) + 28W(M) = 280(M)
From Goose: 100(M) reciprocal, 32(W), 68(T)
40/72 (choose either)
What is the diff between True North and Grid North
Grid convergency
Projection of lambert chart
Earth to cone
What is zenith
The point on the sky vertically overhead an observer
Singapore 01degN, 103degE to Nauru island 00degS (00deg 55S 166deg 91E) find approx dist
3784NM
Dep formula: Chlong (min) X Cos Lat
120degE, LMT is 0724, find UTC at 120deg west
2324 UTC, Previous day
Meridians of longitude
Great circles containing the polar axis
Diagram of changeover point
Choose option with distance 68NM
What is prime meridian
Greenwich meridian
Dep formula can be used to measure
Dist between two points at same latitude
For VFR is sunn is below horizon or high latitudes
Must be large, unique and contrast
Given TAS 270kts, after 20mins, you deviate 3NM to the left of your original track 200degT, what is your actual drift if you have been heading 208degT
10degLeft
Compass North
000 aircraft compass
What is conformity
Angles on earth represented correctly on chart
When is sun directly over 23.5degNorth
4 June
21 June to be exact
When flying VFR, what is the best visual reference to estimate your ground speed
Railway track perpendicular to your flight path
A to B 117NM, one point at 47NM, deviate right 6NM, how many degrees must you change to get back on track
12.9deg
When flying through water
Take note of position and time when passing the edge of water to properly calculate DR to make your next scheduled turn
Lambert conformal, parallel of latitudes
Concave to poles
On a polar stereographic chart with scale of 1:500000 at pole, what is the scale at latitude 82deg
Scale at large = scale at pole X sec2(1/2 co-lat)
1:497567
SAT is
TAT less RR
An aircraft cruising at FL350, TAS430 and ISA+20. What is the Mach number
M0.716
Using chart CH004, locate the fix as measured 55NM from Nelson and 81NM from TORY
S40 24 E173 36
Using chart CH004, locate the intersection point 155T from NS VOR and 217M WN VOR
S41 54 E173 36
Using chart CH004, AC is 315M from Kukuro NDB. What is the true heading from AC to NDB
168T
Define chart convergence
Angular diff between 2 meridians on a chart
Define earth convergence
Chart convergence at parallel of origin
What is the term to describe between Great circle track (GCT) and Rhumb line track (RLT)
Conversion angle
TAS 285kts. Passes VOR at 0834UTC at 133M. At 0850UTC, the VOR radial is measured to be 127 at 80NM. Find wind
245/35 kts
When do you perform a compass swing
As specified in the aircraft maintenance schedule
The ability of compass to align to horizontal component of magnetic field is determined by
Sensitivity
Planned ground speed of a flight plan is 481kts. However, current ground speed displayed in flight by the FMS is 459kts. Aircraft reach waypoint BOLAX at 2344Z. After leaving BOLAX, the next waypoint is GURDI 259NM away, what is the entry to flight log
ZATA BOLAX 2344Z, ZETA GURDI 0018Z
When starting VFR navigation to a waypoint, what is the visual reference that should be picked up to the first waypoint
Pass SHP at cruising altitude
An aircraft start climb from F310 to FL350. Mach0.83 and ISA deviation -5. Find TAS
477kts
The computer flight log of an aircraft flying from waypoint AA to waypoint BB is gen below. What is the fuel burn
8823kg/hr
Question regarding purpose of railway track
Can be used to calculate ATA at right angle to railway track
Question about why are charts constantly being updated and companies have to keep buying charts
Changes in magnetic variation
Question about VFR flights over water and passing a turning point
Take note of the ships on the water as flying safely is more important than navigating on track
Question about chart convergence and earth convergence at Lambert
Earth con and chart con is the same at parallel of origin
When navigating VFR/VMC with the centre of the forest at the turning point, you should
Take note when flying past the edge of the trees and note the time/position to update the DR time. Turn to the next fix with the updated DR time.
31deg South parallel of latitude means
31deg South of equator
Wind velocity 280/20. Desired track 310T, TAS 180. Variation 20W. Calculate heading.
327M or 307T
Given LMT 830PM 3rd March at W121.15, find the UTC
4.34AM 4th March
Mercator Chart scale is 1:2000000 at 30S. What is the scale at 60S
1:1154700
Scale is 1:500000. Actually distance is 88NM. How many cm will that be on the map?
32.6cm
Something about reserve fuel and what is the latest time the plane can proceed with a landing approach
0545
Grid convergence is
Difference between grid North and true north
Compass north is
000 aircraft compass
Question showed lighted obstace
Inverted V - Obstacle
Inverted V with marks on TOP - Lighted obstacle
2 inverted V - Group obstacles
2 inverted V with marks on TOP - Lighted group obstacles
Your start off point to the first way point should be
Prominent landmark which you can obtain upon cruising altitude
True north can be measured from
Clockwise from anti meridian
Convert 238NM to SM
274SM
Why is apparent day not constant throughout the year
Because the earth does not orbit at a constant speed around the sun
Mercator Chart
Expands from the equator
Lambert convergence
Sin x parallel of origin
Purpose of liquid in compass
Dampen oscillations
When to do compass swing
Lightning strike
Compass swing, done when
Major aircraft components change
When is it necessary to swing the direct reading compass of an aircraft
After having been struck by lightning
What would affect compass swing
Magnetic freight
When are Lambert charts used
Mid lat great circles
Triangle of velocities
Vector quantities can be added and subtracted
Standard parallel on the Lambert chart
Cuts the reduced earth
Why are navigational maps constantly updated
Because the magnetic variation changes with time
Modern navigational charts are considered as
Mathematical and still a projection
What is layered tinting/coloured gradient
Used for ground in different elevation bands
What are contour lines
Lines of same elevation
AC cruising at 240kts TAS waypoint 1. Track and dist to waypoint 2 is 040T/120nm. The forecast W/V is 180deg T/30. What is elapsed time to waypoint 2
27min
X wind = wind speed x sin (Bigger angle - Smaller angle)
HDW Windspeed x cos (Bigger angle - Smaller angle)
What dist from the departure point will an aircraft reach FL350 if it departs from overhead at AL of 3000ft
Mean climb TAS = 230kts
Mean ROC = 1150fpm
Wind component for climb = +30kts
+ is tailwind, - is headwind
120nm
How are great circles compared to thumb lines with respect to the equator/pole
Convex to pole
What do the numbers mean on the following diagram?
Diagram shows a changeover point
The distance from and to changeover point
Ram rise is
Difference between RAT and SAT
RAT is
RR plus SAT
Lambert chart, great circles are
Concave to the parallel of origin
Your dist to go is 850nm, speed is 420Kts, wind component is -30. Calculate the time required to cover this distance
131 mins
RMI gives you a heading of 252M, variation at AC is 28W, variation at VOR is 32W. What is the bearing of your true plot form the VOR to you
Given - Goose VOR: 53N60W Aircraft: 56N55W
- Find true heading - 252 - 28 = 224T
2. Find true track = Approx less than 76M
A Lambert chart scale
Where differences between the standard parallels is 1%…
Flight log question Fly 10N45W UTC time from 0303 to 0354 Find average ground speed Use figure above ZATA (419nm) Time travelled 51 mins Average groundspeed kts
493kts
True direction is measured from
Clockwise from any meridian
Total fuel tank capacity 325 litres Total fuel on board 68USG (257l) Flight time 1h17min Fuel filled 198l to full tank AVGAS sg 0.72 Find fuel burn rate
162lbs/h
Start time 0445 UTC Fuel amt: 6700kg
2nd time check 0505UTC Fuel amt: 5900kg
Fuel for approach: 650kg
Fuel for missed approach, diversion and reserve fuel: 3300kg
Latest time to descend
0546UTC
0554UTC
To an observer on the North Pole, your earth rotate_____ and the earth rotates around the sun _____
Anti clockwise, Anti clockwise
Back bearing is the
Reciprocal of bearing from the observer
Radio bearing is referred to as
The reciprocal bearing to the observer
The RMI of an NDB from the aircraft is 325M. What is the bearing to plot from the NDB in T given that you are 35nm from the NDB
Plotting 35nm will help you see the variation line, which is stated on the chart as 23E.
Therefore, bearing to plot = 145M + 23E = 168T
They will give you a flight log
8253 or smth like that
What errors would you encounter when converting indicated Airspeed to Calibrated Airspeed
Position and Instrument error
IOAT/TAT/RAT
SAT(COAT) =
TAT (IOAT/RAT) - Ram Rise
RAT =
COAT + Ram Rise
IOAT =
OAT + Ram Rise
TAT =
SAT + Ram Rise
How are parallel of Latitude like on Mercator Chart?
Straight lines (+ Expanding away from the equator)
On a polar stereographic chart, a scale at the pole what is the scale at latitude 80deg
Use formula:
Scale at lat = scale at pole X sec2 (1/2 co-lat)
Given TAS 220kt, Flying from 3000ft to 15000ft, flying a TK of 66T. Average ground speed?
Ascend: 2/3 X higher altitude
Descend: 1/2 X Lower altitude
Use CRP5 to find HDG (do drift correction)
224 - 226kts
2 qn on air almanac.
Interpolate between 2 numbers, then convert to LMT of given longitude (15deg = 1hr)
Asked about the oblate spheroid shape of the earth. Qn was whether the diameter is longer at where
Diameter is longer over the equator than the poles
Diff is 43km