Navigation Flashcards
How long is 1 nautical mile?
1852m
What projection is a VTC?
Transverse Mercator projection
Which way does longitude increase in the western hemisphere?
Higher numbers to the left
How much time is in 1 degree of longitude?
4 minutes
How much time is in 15 seconds of longitude?
1 minute
What are the considerations for Part 91 fuel planning?
Trip fuel
Fixed reserve
Holding
Alternate
Taxi
What are the considerations for Part 135 planning?
Flight fuel
Contingency fuel
Fixed reserve
Holding fuel
Alternate
Taxi fuel
How to calculate contingency fuel
10% of flight fuel unless less than 5 minutes in which case 5 minutes at hold rate
How much if fixed reserve part 91?
30 minutes at holding rate
Fixed reserve for part 135?
45 minutes at holding rate
What are the ADF/NDB errors?
Mountain effect
Interference, co channel
Night effect
Terrain effect
Coastal refraction
A/C quadrantal error
Thunderstorm effect
What is mountain effect?
Mountains may reflect NDB signals and produce erroneous readings - ADF may receive several reflected signals with resultant fluctuations
What is interference error?
Two closely located NDB’s with the same frequency may produce erroneous signals
What is night effect?
By night, sky waves are not absorbed and are refracted off the ionosphere and reflected back to earth. The ADF cannot distinguish between ground waves and sky waves and gives erroneous indications
What is terrain effect?
Sandy or rocky terrain conducts radio waves poorly, so attenuation of the waves is greater over land than over water
What is coastal refraction?
Radio waves can be refracted as they pass over the coast. This causes false bearing indications as the NDB appears closer to the coast than it really is. This can be avoided by using NDB’s closer to the coast when flying over water
What is thunderstorm effect?
The electrical energy around a thunderstorm may attract an ADF needle
How could you identify NDB station passage?
Needle starts to wobble as approaching overhead
Needle drops to bottom
What is the formula to find pressure height?
ALT + 30(1013-QNH)
What is the formula to find density height?
Pressure height + 120(OAT-ISA T)
What is the formula to find ISA temperature?
15 - (2 x (pressure height/1000))
When does BOD and EOD occur?
Sun within six degrees of the observers horizon
What is the period between BOD/EOD and sunrise/sunset?
Civil twilight
What does each dot on either side of the centre of an OBI mean?
Each dot is 2 degrees of angular displacement
What are the errors of a VOR?
Airborne
Vertical polarisation
Ground station error
Aggregate
Site (terrain) effect
What is airborne VOR error?
Equipment itself in the aircraft - usually +/- 2 degrees
What is vertical polarisation error for VOR?
VOR signals are horizontally polarised and sometimes terrain can cause the signal to be vertically polarised - when the aircraft is in a bank it can cause some abnormal movements of the CDI
What is VOR ground station error?
The actual ground equipment itself and is usually less than +/- 2 degrees
What is aggregate VOR error?
The sum of all VOR errors and always less than +/- 5 degrees
What is site effect for VOR?
Rough terrain effecting the radial. If slow it’s called bending and if fast it’s called scalloping.
Less than +/-2 degrees
How can you identify passage over a VOR station?
Needle becoming more sensitive and oscillating as you approach the station
Red flag appearing indicating an unusable signal
The TO flag being replaced by FROM
The needle becoming more stable after station passage
How many GNSS satellites are required for a 2D position?
At least three
How many GNSS satellites are required for an accurate 3D position?
At least four
How does RAIM fault detection work?
Compared position and time information derived from combinations of four inputs from a set of five satellites, or four satellites and a barometric source
What does GNSS fault detection and exclusion need?
Six inputs
