NAV Flashcards
What is a barometer used to measure?
Atmospheric Pressure
What is an altimeter used to measure?
Altitude
A Dyne is equal to 00001 Newtons, and a Hectopascal is equal to how many Dynes?
1000 per square cm
Pressure is?
Force per unit area
Pressure and Altitude are inversely proportional at least in the troposphere, what does this mean?
As altitude increases, pressure decreases.
Pressure and density are proportional, what does this mean?
As pressure decreases, density decreases.
What is a wet bulb thermometer and how does it work?
It is a thermometer wrapped in wet cloth. The evaporation of water has a cooling effect on the thermometer, and when all of the water is evaporated, the atmospheric saturation, or relative humidity can be calculated.
What is ISA standard atmospheric pressure at MSL?
1013.25hPa or 29.2 inches of mercury.
What is ISA temperature at MSL?
15 degrees celcius
What is the ELR outlined in the ISA?
-1.98 degrees celcius per 1000ft
Define height?
Vertical distance of a point measured from a specific datum
Define altitude?
Vertical distance of a point measured from MSL
Define elevation?
Vertical distance of a point or level on the surfrace of the Earth measured from MSL
What is QFE?
Query Field Elevation. Atmospheric pressure corrected to a specific elevation.
What is aerodrome elevation?
The elevation of the highest point of the landing area
What is QNH?
Query Nautical Height. Atmospheric Pressure Corrected to MSL, assuming ISA conditions.
Define level?
Generic term relating to the vertical position of an aircraft in flight and meaning variously: height, altitude, or flight level.
Define flight level?
A surface of constant atmospheric pressure, which is related to a specific pressure datum, 1013.25hPa, and is separated from other such surfaces by specific pressure intervals (ICAO 4444)
FL intervals can vary below FL200. How so?
500ft intervals allowed below FL200, 1000ft intervals only above FL200
Define QDR?
Magnetic bearing of the aircraft to the airfield.
Define QDM?
Magnetic track from the aircraft to the airfield. Reciprocal of QDR.
Define QTE?
True bearing of aircraft from the DF station.
Define QUJ?
True track required to reach the DF station.
What is a precision approach aid?
An approach aid providing elevation information.
What 2 beams does an ILS emit?
Localiser (Azimuth), and Glidepath (Elevation)
What is the usual descent angle of a glidepath?
3 degrees
Glidepath coverage in the vertical plane typically extends?
From 0.45 to 1.75 times the glidepath angle.
From what direction should an a/c attempt to intercept the glidepath?
From underneath or from the side.
What is ILS Cat I?
RVR 550m
Decision Height 200ft
What is ILS Cat II
RVR 250m
Decision Height 100ft
What is ILS Cat IIIa
RVR 200m
decision Height 0ft
What is ILS Cat IIIb
RVR 50m
Decision Height 0ft
What is ILS Cat IIIc
RVR 0m
Decision Height 0ft
How many ILS categories are there?
5
In reality, which ILS Category is never used?
Cat IIIc
Name some limitations of ILS?
Inflexible, expensive, beam must always be protected, aircraft must be fully out of the way before next plane can approach to land.
What frequency band do the Localiser and Glidepath work on?
Localiser VHF
Glidepath UHF
What will happen as an a/c passes through the ILS outer, middle, and inner markers?
Lights and sounds in the cockpit will inform the pilot once passing each of these phases.
An instrument approach contains 5 phases. Name them?
Initial Approach Fix (IAF), Intermediate Approach Fix (IF, Final Approach Fix (FAF), Final Approach Point (FAP), Missed Approach Point (MAPt)
What is the missed approach point?
The point at or before a missed approach procedure must be implemented to ensure minimum obstacle clearance is not infringed.
What is a minimum descent height/altitude?
in a non-precision approach below which a descent may not be made without the required visual reference.
Waypoints are usually how many letter designators that should spell a pronounceable word?
5
INS means?
Intertial Navigation systems. An en-route navigation aid. Comprises also of programmed waypoints but accuracy decays so must be updated regularly otherwise GIGO - Garbage In Garbage Out.
FMS Means?
Flight Management System. Varies in complexity with newer models almost completely guiding the plane from take-off to landing.
The FMS gathers data from?
Multiple sources, including INS and NAVAIDS to ensure the aircraft is performing as desired. It feeds the autopilot.
FDI means?
Flight Director Interface. Pilot can update changes to the preprogrammed flight here.
GPS means?
Global Positioning System. Precision 3D satellite navigation aid. operates on 2 L band frequencies: 1557.42 MHz and 1227.6 MHz
Limitations of GPS?
Availability of satellites, signal degredation, military control
What is a VOR?
Very High Frequency Omni-Directional Range. An en-route and terminal instrument approach aid. Orientated to magnetic north and emits 360 radials to plus or minus 1 degree accuracy. The receiver compared the phase difference between the 2 signals and determines the a/c bearing from the station.
What is a CDI?
Course Deviation Indicator. Part of a VOR instrument that shows a/c alignment with desired VOR radial.
DME is often collocated with?
VOR
DME suffers from a type of error know as?
Slant error. Less prevalent at lower altitudes where the diagonal distance doesn’t necessarily align with horizontal distance from the station.
NDB is a?
Non Directional Beacon. A basic en-route and approach aid that emits a radio signal equally in all directions which a pilot navigates towards.
You may see multiple NDB’s in mountainous regions. Why?
They operate in a line of sight manner so multiple are needed to navigate mountainous areas where their signal may be blocked.
NDB’s can suffer from many types of interference. Name them?
Station interference, night effect, coastal refraction, mountain effect, quadrantal error
Coastal refraction does not occur when?
When a/c is crossing the coastline at 90 degrees.
Quadrantal error occurs when?
When the signal does not align with the nose/wings/tail but enters the spaces in between them.
