BAK Flashcards
What unit of measurement is used for distances in navigation?
Nautical Miles
What unit of measurement is used for short distances in navigation?
Metres
What unit of measurement is used for altitudes, elevations and heights?
Feet
What unit of measurement is used for vertical speed?
Feet Per Minute
What unit of measurement is used for wind direction for runway operations?
Degrees Magnetic
What unit of measurement is used for horizontal speed, including wind speed?
Knots
What unit of measurement is used for wind direction for non-runway operations?
Degrees True
What unit of measurement is used for altimeter setting?
Hectopascals
What unit of measurement is used for temperature?
Degrees Celsius
What unit of measurement is used for weight (mass)?
Tonnes or Kilograms
What unit of measurement is used for time?
Hours and Minutes
What defines Visual Meteorological Conditions? (VMC)
The aircraft must remain 1500m horizontally and 1000ft vertically away from the cloud. Above 10,000ft visibility must be 8000m and below 10,000ft the visibility must be 5000m.
What is QNH, and what is the international standard atmospheric pressure?
QNH is the static pressure at sea level for a location. The international standard QNH is 1013.2hPa.
At or below what QNH is FL110 not available?
1013hPa
At or below what QNH is FL115 not available?
997hPa
At or below what QNH is FL120 not available?
980hPa
At or below what QNH is FL125 not available?
963hPa
Which altitude should a westbound VFR flight above 3000ft cruise at?
Even thousands + 500ft, ie. 4500ft
Which altitude should an eastbound VFR flight above 3000ft cruise at?
Odd thousands + 500ft, ie. 3500ft
Which altitude should a westbound IFR flight above 3000ft cruise at?
Even thousands, ie 4000ft
Which altitude should an eastbound IFR flight above 3000ft cruise at?
Odd thousands, ie. 3000ft
What is a Minimum Safe Altitude?
Specified for sectors surrounding a navigation aid, marked on charts as a circle centred on that aid.
What is a “Lowest Safe Altitude” (LSALT)?
Marked on map routes and provide a 1000ft obstacle clearance. May only apply in one direction shown by an arrow.
What is a Gris LSALT?
A Lowest Safe Altitude reading displayed in the centre of a grid square on some maps as a large number (representing thousands of feet) followed by a superscript number (representing hundreds of feet).
What is Indicated Air Speed (IAS)?
The speed of the aircraft through the volume of air. Varies with changes in density.
What is True Air Speed (TAS)?
The speed of the aircraft relative to the airmass in which it is flying.
What is Ground Speed?
The horizontal speed of the aircraft relative to the ground.
How would you find your current position on the Earth?
Using co-ordinates of latitude and longitude.
How would you find the shortest distance from point A to point B on the Earth’s surface?
Using the Great Circle method, as the Earth is a globe.
Your destination is 90 degrees on the map from your present location. Magnetic Variation is 12 degrees East, what heading should you set on your compass?
Variation East, Magnetic Least. 78 degrees.
Your destination is 90 degrees on the map from your present location. Magnetic Variation is 12 degrees West, what heading should you set on your compass?
Variation West, Magnetic Best. 112 degrees.
What is morning civil twilight?
In the morning, when the sun is 6 degrees below the horizon to when it first appears.
What is evening civil twilight?
The period from when the top of the sun disappears below the horizon to when the middle of the sun is 6 degrees below the horizon.
What is Local Mean Time (LMT)?
A time reference to the position of the sun.
What is the World Aeronautical Chart (WAC)?
Used for visual flying. Contains topographical information, airports and nav aids. Does not portray any air routes or airspace boundaries.
What is an Enroute Chart (ERC)?
Used for instrument flying. May be for either high or low level air routes (ERC HIGH or ERC LOW). Contains detailed information on published air routes. Details include magnetic tracks, distances and lowest safe altitudes. These charts also include airports, nav aids, airspace boundaries and frequency information. ERC charts typically cover a wide area similar to those of WAC charts.
What is a Visual Termination Chart (VTC)?
Used for visual flying. Contains topographical information, airports, nav aids, airspace boundaries and frequency information focused on a particular airport’s immediate terminal area.
What is a Departure Chart (SID)?
Used for instrument departures. Contains illustration and narrative instructions for an aircraft to get from the departure runway to the enroute phase of the flight. Included are routes, waypoints and procedures that provide aircraft adequate obstacle clearance and strategic separation.
What is an Approach Chart (STAR)?
Used for instrument arrivals. Contains illustrative and narrative instructions for an aircraft to get from the enroute phase of the flight to the initial approach fix, in order to begin an instrument approach. Included are routes, waypoints and procedures that provide aircraft adequate obstacle clearance and strategic separation.
What is a Landing Chart?
Used for instrument approaches. Contains illustrative and narrative instructions for an aircraft to get from an initial position fix to the arrival runway. Included are key waypoints and altitudes that provide aircraft adequate obstacle clearance and strategic separation.
What is the composition of air on the Earth’s surface?
78% Nitrogren, 21% Oxygen, 1% Argon, 0.04% Carbon Dioxide, 1% Water Vapour
If the air contains more water vapour, how might this affect particle density?
Less moisture results in higher air density.
What is the Dry Adiabatic Lapse Rate (DALR)?
3 degrees celcius per 1000ft of altitude
What is the Saturated Adiabatic Lapse Rate (SALR)?
1.5 degrees celcius per 1000ft of altitude
Which direction does air in a low-pressure system in the Southern Hemisphere travel?
Clockwise
Which direction does air in a high-pressure system in the Southern Hemisphere travel?
Anti-clockwise
What is conduction?
Conduction occurs when two objects at different temperatures are in contact with each other. Heat flows from the warmer to the cooler object until they are both at the same temperature.
What is convection?
When a fluid, such as air or a liquid, is heated and then travels away from the source, it carries the thermal energy along. Also known as vertical advection.
What is advection?
The transfer of heat or matter by the flow of a fluid, especially horizontally in the atmosphere or the sea.
What is radiation?
Radiation is the transfer of energy by electromagnetic radiation.
How do thermals work?
A thermal is a rising mass of warm air. As the land heats up it conducts its heat energy to the air in contact with it. The vibrating air molecules begin to push harder on each other, forcing them apart. The pressure remains constant and the result is a change in density. The warmer air is less dense than the surrounding air and therefore rises.
Good conductors of heat energy such as cities, bitumen road and darker areas produce good thermals. Lighter areas such as swamps and forests produce little thermals and can actually be areas of sinking air.
What is dewpoint?
Dewpoint is defined as the temperature of a parcel of air when cooled at constant pressure in order that it will become saturated i.e. reach 100% relative humidity. Further cooling of the air will result in condensation
occurring. We see this at night when the ground cools, the air in contact with it cools to its dewpoint, and dew forms.
Dewpoint decreases with height (due to pressure decrease) at about 0.5° per 1000 feet. When water condenses (from a vapour to a liquid) it is has reached its Dewpoint.
How are cloud amounts reported on?
Sky clear is for 0 okta; Few is for 1 to 2 oktas; Scattered is for 3 to 4 oktas; Broken is for 5 to 7 oktas; and Overcast is for 8 oktas
What are the three pre-cursors to a thunderstorm?
- High Humidity
- Atmospheric Instability
- A trigger to push air upwards, such as the approach of a cold front.
What are the four kinds of icing that can occur?
- Rime - tiny supercooled droplets freezing on the airframe
- Clear - flying through freezing rain
- Mixed - rime and clear, determined by droplet size
- Hoar Frost - moist air + freezing surface
What are the three pre-cursors to icing?
- Visible moisture or crystals are present.
- Temperature must be near freezing (-40 to +10)
- The airframe temperature must be below 0 degrees celcius
What is the purpose of an anemometer?
Measure wind speed
What is the purpose of a wind vane?
Measure wind direction
What is the purpose of a barometer?
Measure air pressure
What is the purpose of a dry bulb thermometer?
Measure ambient air temperature
What is the purpose of a wet bulb thermometer?
Measure dew point air temperature
What is the purpose of a Stevenson Screen?
Instrument shelter
What is the purpose of a wind sock?
Wind Direction Indicator
What is the purpose of a radiosonde?
A device attached to a weather balloon to send instrument data of the atmosphere to a ground station
What is the purpose of a weather balloon?
Collect atmospheric data.
What is wind shear?
A difference in wind speed or direction over a relatively short distance in the atmosphere.
What is the relationship between frequency and wavelength?
Inversely proportional
List the characteristics of HF frequencies.
Allows communication with aircraft in:
- remote areas
- over the horizon
- out to sea beyond line-of-sight
Limitations:
- Very susceptible to interference
- Fading due to the interaction of ground and sky waves
- Affected by ionosphere
- Difficult to silence receivers
- HF antenna arrays are large
List the characteristics of UHF frequencies.
- Same as VHF
- Used for military purposes
List the characteristics of VHF frequencies.
Useful for:
- ATC
- GA
- Radio navigation aids
Limitations:
- Limited in coverage to LOS
- Mountain-top sights for ground equipment necessary
- Coverage of large areas requires repeaters
Advantages:
- Good signal quality
- Wave are direct
- Small antennas
- Low transmitter power requirement
What is SELCAL?
SELCAL replaces voice with coded tones. There are a combination of four audio tones. HF communications are very vulnerable to interference, particularly from atmospherics. It is technically difficult to silence receivers between incoming communication signals. This means pilots are required to listen to annoying ‘hash’ continually whilst awaiting calls directed to their aircraft. SELCAL silences the receiver until a relevant tone is received.
What is CPDLC?
CPDLC allows a sophisticated text based exchange between ATC and pilots which mirrors voice communications. Literally any exchange possible by voice, whether VHF or HF, can be accomplished using text based CPDLC.
What is the total reaction vector?
The balance of four forces acting on an aircraft in flight:
- Thrust vs Drag
- Lift vs Weight
What is the centre of pressure?
The point on an aircraft where the lift force acts. Also known as the aerodynamic centre.
What is wake turbulence?
Vortices generated from the wings spread laterally away from the aircraft and descend 500 to 1000ft at distances of up to 5 miles behind it.