NCAA PPL Navigation flashcards
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32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Nautical mile
- A unit of distance equal to one minute of latitude, about 6,076 feet or 1.852 kilometers. It is the standard unit for air and sea navigation and is used for groundspeed, distance, and fuel planning.
- Knot
- A unit of speed equal to one nautical mile per hour. Groundspeed and true airspeed are normally expressed in knots, and time en route is computed by dividing distance in nautical miles by groundspeed in knots.
- True course
- The intended path over the ground measured in degrees clockwise from true north. It is plotted on a sectional chart with a plotter and converted to magnetic course by applying variation.
- True heading
- The direction the aircraft nose points, measured from true north. It equals true course plus or minus the wind correction angle, and is the value used before applying magnetic variation.
- Magnetic heading
- The heading measured from magnetic north, obtained by applying variation to true heading. East variation is subtracted and west variation is added, following the rule east is least, west is best.
- Compass heading
- The heading actually shown on the magnetic compass after applying deviation to magnetic heading. Deviation is read from the aircraft's compass correction card and varies with heading.
- Variation
- The angular difference between true north and magnetic north at a given location, shown by isogonic lines on charts. It changes with position and is applied to convert between true and magnetic directions.
- Deviation
- The error of a specific magnetic compass caused by aircraft magnetic fields, read from the compass correction card. It is applied after variation to obtain the compass heading to fly.
- Wind correction angle
- The angle between heading and course needed to offset wind drift. It is computed from wind speed, wind angle, and true airspeed, and the aircraft is crabbed into the wind to hold the desired track.
- Groundspeed
- The actual speed of the aircraft over the ground, equal to true airspeed adjusted for the wind component along the course. It determines time en route and fuel consumed per mile.
- True airspeed
- The speed of the aircraft through the air mass, corrected for altitude and temperature. It increases about two percent per thousand feet for a given indicated airspeed and is used in the wind triangle.
- Wind triangle
- A vector diagram in which the wind vector plus the air vector equals the ground vector. Solving it yields groundspeed and wind correction angle from wind direction, wind speed, and true airspeed.
- Pilotage
- Navigation by visual reference to landmarks such as towns, rivers, highways, and airports. It requires good visibility and recognizable checkpoints and is often combined with dead reckoning.
- Dead reckoning
- Navigation by calculating position from a known starting point using heading, time, and speed. It does not require ground reference but depends on accurate wind and heading information.
- VOR radial
- A magnetic bearing extending outward FROM a VOR station. To fly toward the station on a given radial, the pilot sets the OBS to that radial and flies the reciprocal heading with a TO indication.
- Course deviation indicator
- The needle on a VOR display showing displacement from the selected course. Each dot represents about two degrees, and full-scale deflection means the aircraft is at least ten degrees off course.
- Time to VOR station
- A method using radial change to estimate distance. Turn ninety degrees, time until the CDI centers, then time to station equals elapsed time times sixty divided by degrees of radial change.
- DME slant range
- The line-of-sight distance from the aircraft to a DME station, which reads slightly high compared with ground distance. Ground distance equals the square root of DME squared minus altitude squared.
- GPS RAIM
- Receiver autonomous integrity monitoring, a function that predicts whether enough satellites are available to provide reliable GPS position. Pilots check RAIM before departure for long cross-countries.
- Sectional chart scale
- A scale of 1:500,000, meaning one inch on the chart equals about eight statute miles or 6.86 nautical miles on the ground. Terminal area charts use a larger 1:250,000 scale.
- Isogonic line
- A line on a chart connecting points of equal magnetic variation. The agonic line has zero variation, and the labels east or west indicate how variation is applied to true course.
- Class B airspace
- Controlled airspace around large airports depicted by solid blue lines. A pilot must receive an explicit clearance before entering, and the aircraft must have a transponder with Mode C.
- Class C airspace
- Controlled airspace around medium airports shown by solid magenta lines. Entry requires two-way radio communication and a transponder with Mode C, but no explicit clearance is needed.
- Class D airspace
- Controlled airspace around airports with operating control towers, shown by dashed blue lines. Two-way radio contact is required before entry, and the airspace typically extends to about 2,500 feet.
- Class E airspace floor
- The lower limit of Class E airspace, shown by magenta shading at 700 feet AGL or blue shading at 1,200 feet AGL. Class G airspace lies below that floor where it exists.
- Special use airspace
- Airspace with restrictions or hazards, including prohibited, restricted, warning, military operations, and alert areas. Pilots must check charts and notices before planning a route through them.
- Chart Supplement
- A publication containing airport data not shown on sectionals, such as runway lengths, frequencies, pattern altitudes, and special notices. It replaces the former Airport/Facility Directory.
- Altimeter setting
- The pressure value set on the altimeter to make it read true altitude at the departure or destination airport. Flying from high to low pressure without adjustment makes the aircraft lower than indicated.
- Density altitude
- Pressure altitude corrected for nonstandard temperature, approximately pressure altitude plus 120 times the difference between actual and standard temperature. High values reduce climb and cruise performance.
- VFR fuel reserve
- Fuel that must remain at landing, thirty minutes during the day and forty-five minutes at night for VFR flight. It is added to trip fuel when planning each cross-country leg.
- Transponder code 7700
- The emergency squawk code that alerts air traffic control to a distress situation. Related codes are 7600 for radio failure and 7500 for unlawful interference.
- Lost procedures
- Steps taken when position is uncertain: climb for better radio and visual range, circle, use VOR cross-bearings or GPS to fix position, and declare an emergency on 121.5 MHz if unable.