DGCA ATPL Air Navigation flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

1 NM in km

One nautical mile equals 1.852 kilometres and equals one minute of arc of latitude on the Earth's surface.

Departure formula

Departure in nautical miles equals change of longitude in minutes multiplied by the cosine of the mean latitude.

Variation east, magnetic least

When variation is east, subtract it from true heading to obtain magnetic heading; when west, add it.

Conversion angle

Half the change of longitude multiplied by the sine of the mean latitude, giving the angle between rhumb line and great circle.

VOR radial meaning

A VOR radial is the magnetic bearing from the station; the selected course with a TO flag points toward the station.

DME slant range

DME measures slant range; ground distance equals the square root of slant range squared minus altitude squared.

ILS localizer tones

The localizer uses 90 Hz on the left and 150 Hz on the right; fly toward the side with the stronger signal.

ADF relative bearing

The ADF needle shows relative bearing; adding magnetic heading gives the magnetic bearing to the station.

GNSS RAIM

Receiver Autonomous Integrity Monitoring detects faulty satellites; adequate geometry (low HDOP) is required for the approach.

Point of no return

Equal-time point distance from departure equals total distance times outbound ground speed divided by the sum of outbound and return ground speeds.

Contingency fuel

Typically five percent of trip fuel, carried to cover unforeseen deviations from the planned route or forecast conditions.

Specific range

Air distance flown per unit of fuel; maximum specific range occurs near the tangent from origin to the fuel-flow versus TAS curve.

Track error correction

Correction equals track error plus closing angle; apply toward the desired track to regain the planned path.

ISA temperature lapse

Temperature decreases 1.98 degrees Celsius per 1000 feet up to 36,090 feet, where it reaches minus 56.5 degrees Celsius.

Cold-air altitude correction

When temperature is below ISA, true altitude is lower than indicated; add four feet per degree Celsius per 1000 feet.

QNH versus QFE

QNH set on the subscale gives elevation above mean sea level; QFE gives height above the aerodrome reference point.

Jet stream core

A jet stream core has winds of at least 60 knots near the tropopause; clear air turbulence is most likely on the cold side.

Centre of gravity formula

Centre of gravity equals total moment divided by total mass, where each moment is mass multiplied by its arm.

Percent MAC

Percent MAC equals centre of gravity minus leading edge MAC, divided by MAC length, multiplied by 100.

CG shift formula

Change in centre of gravity equals mass moved multiplied by distance moved, divided by total mass.

Zero fuel mass

Zero fuel mass equals take-off mass minus take-off fuel; it must not exceed the maximum zero fuel mass.

Balanced field length

The runway length where accelerate-stop distance equals accelerate-go distance to 35 feet, defining the V1 speed.

V2 take-off safety speed

V2 is at least 1.13 times the stall speed in the take-off configuration, reached at 35 feet above the runway.

Landing distance factor

Landing distance required multiplied by 1.67 for dry or 1.92 for wet runways must not exceed landing distance available.

Density altitude effect

Higher temperature and pressure altitude increase density altitude, lengthening take-off and landing distances and reducing climb performance.

Pitot blockage effect

With the pitot blocked and static clear, the airspeed indicator behaves like an altimeter, increasing in climb and decreasing in descent.

IRS drift

Inertial reference systems drift about one to two nautical miles per hour; position must be updated with radio or GNSS fixes.

Radio altimeter range

The radio altimeter measures height above terrain from zero to about 2500 feet and is used for approach and ground proximity warning.

Semi-circular rule

Magnetic tracks 000 to 179 degrees use odd flight levels; tracks 180 to 359 degrees use even flight levels above the transition altitude.

Transition altitude

The altitude at which the altimeter is set to 1013.2 hectopascals; above it, flight levels are used for vertical separation.

RVSM airspace

Between flight levels 290 and 410, 1000-foot vertical separation applies, requiring approved altimetry and autopilot equipment.

Position report content

A position report contains aircraft identification, position, time, flight level, next position and estimated time over it.