PPL Navigation & Communication Theory flashcards
PPL Navigation & Communication Theory · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Great circle
- The shortest path between two points on the surface of a sphere; its track crosses each meridian at a different angle except at the equator and the vertex.
- Rhumb line
- A line of constant track angle relative to all meridians; it is longer than the great circle except along the equator or a meridian.
- Departure formula
- Departure in nautical miles equals change of longitude in minutes multiplied by the cosine of the mean latitude; it gives east-west distance along a parallel.
- Mercator projection
- A chart projection with parallel meridians and straight rhumb lines; scale increases with latitude, making it unsuitable for great-circle plotting without a graticule.
- Lambert conformal conic
- A chart projection with standard parallels where scale is exactly correct; great circles plot approximately as straight lines and it is used for ICAO area charts.
- AIP structure
- The Aeronautical Information Publication has three parts: GEN for general, ENR for en-route and AD for aerodromes; NOTAMs and AICs amend it.
- Wind triangle
- A vector triangle combining heading and true airspeed with the wind vector to give track and groundspeed; drift is the angle between heading and track.
- One in sixty rule
- A one-degree track error over 60 nautical miles gives one nautical mile off track; off-track distance equals distance flown times error divided by 60.
- Crosswind component
- The crosswind component equals wind speed multiplied by the sine of the angle between the wind and the runway or track.
- VOR radial
- The magnetic bearing from a VOR station to the aircraft; a TO indication means the selected course leads towards the station.
- DME slant range
- DME measures slant range, which exceeds ground distance; the error is significant at high altitude and close range.
- RAIM
- Receiver autonomous integrity monitoring uses redundant satellite measurements to detect and exclude faulty satellites; at least five satellites are needed for detection.
- MAYDAY and PAN PAN
- MAYDAY is the distress call for immediate danger and has priority over all communications; PAN PAN is the urgency call for safety without immediate danger.
- Readback requirement
- Route clearances, hold short instructions, level instructions, headings and altimeter settings must be read back with the aircraft call sign.
- Transponder codes
- Squawk 7700 for emergency, 7600 for radio failure and 7500 for unlawful interference; Mode C reports pressure altitude.
- ISA conditions
- International Standard Atmosphere: sea level 15 degrees Celsius and 1013.25 hPa, with temperature decreasing about 1.98 degrees per 1,000 ft to the tropopause.
- QNH and QFE
- QNH gives altitude above mean sea level; QFE gives height above the aerodrome reference point; QNE at 1013.25 gives flight level.
- Cold temperature altimetry
- In air colder than ISA the altimeter over-reads, so true altitude is lower than indicated and terrain clearance is reduced.
- Semi-circular rule
- Magnetic tracks 000 to 179 use odd flight levels and tracks 180 to 359 use even flight levels, separated by 1,000 ft or 2,000 ft above FL290.
- Class G airspace
- Uncontrolled airspace where no separation service is provided; pilots rely on see-and-avoid and may use a flight information service.
- Special VFR
- A clearance allowing VFR flight in controlled airspace below VMC; the pilot must remain clear of cloud and in sight of the ground.
- Convergency
- The angle between two meridians, equal to change of longitude multiplied by the sine of the latitude; all meridians meet at the poles.
- Conversion angle
- Half the convergency, equal to 0.5 times change of longitude times sine of mean latitude; used to convert great circle to rhumb line bearings.
- Equation of time
- The difference between apparent solar time and mean solar time, varying up to about plus or minus 15 minutes; relevant to sunrise and twilight calculations.
- Final reserve fuel
- Fuel required to hold for 30 minutes at 1,500 ft above the alternate aerodrome in ISA conditions for commercial transport aeroplanes.
- Point of no return
- The point beyond which the aircraft cannot return to the departure aerodrome with the fuel remaining; calculated from endurance and groundspeeds.
- Specific range
- Air distance flown per unit of fuel; maximum range is achieved near the speed for best lift-to-drag ratio.
- ILS categories
- CAT I has a 200 ft decision height and 550 m RVR; CAT II 100 ft and 300 m; CAT III allows lower or zero decision height with autoland.
- Holding pattern entry
- Standard turns are right-hand with one-minute inbound legs below 14,000 ft and 1.5 minutes above; entry is direct, parallel or teardrop.
- Missed approach point
- The point where the missed approach must be initiated if the runway is not in sight; it may be a fix, a DME distance or a time.
- Geostrophic wind
- Wind that blows parallel to straight isobars when the pressure gradient force balances the Coriolis force; surface friction makes it cross isobars.
- Buys Ballot's law
- In the northern hemisphere, with your back to the wind, low pressure is on your left; in the southern hemisphere it is on the right.