Mauritius DCA ATPL Theory flashcards

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

Semi-circular rule

A flight level rule based on magnetic track: tracks 000 to 179 degrees use odd levels, and tracks 180 to 359 degrees use even levels, at 1 000 ft intervals.

Right of way, head-on

When two aircraft converge head-on at roughly the same level, both must alter heading to the right so they pass port side to port side.

MAYDAY and PAN PAN

MAYDAY is the radiotelephony distress signal for grave and imminent danger requiring immediate assistance; PAN PAN signals urgency but no immediate danger.

Essential bus

An electrical bus fed from the battery or a standby source so that flight instruments, radios and essential equipment remain powered after generator failure.

NiCd charging characteristic

Nickel-cadmium batteries require a constant-voltage charge, while lead-acid batteries require constant current; using the wrong regime shortens life and risks thermal runaway.

EGT limit

Exhaust gas temperature is limited because it indicates turbine blade temperature; exceeding the limit can damage the turbine, so it is a hard limit.

Cold temperature altimeter error

In air colder than ISA, the altimeter over-reads, so the true altitude is lower than indicated; this is significant when flying at low temperatures near terrain.

Blocked static port

With the static port blocked, the airspeed indicator over-reads in a climb and under-reads in a descent, while the altimeter freezes at the blockage altitude.

Standard rate turn

A turn of 3 degrees per second, completing 180 degrees in one minute; the turn coordinator shows this rate on its marked index.

Maximum zero-fuel mass

The maximum mass of the aircraft with usable fuel excluded; it limits structural loading and ensures the wing root and fuselage are not overstressed.

Centre of gravity shift

Moving a mass aft of the CG moves the CG aft by an amount proportional to the mass and its distance from the original CG, divided by total mass.

Forward CG effects

A forward CG increases stick force, lengthens the take-off run, raises the stall speed and reduces range, but improves longitudinal stability.

Balanced field length

The shorter of the accelerate-stop distance and the accelerate-go distance to 35 ft; it is the field length that balances the two cases.

Density altitude

Pressure altitude corrected for temperature; it rises with high temperature and high pressure altitude, increasing take-off and landing distances and reducing climb performance.

Contingency fuel

Fuel carried in addition to trip fuel, normally 5 percent of trip fuel, to cover unforeseen deviations such as weather, routing or ATC delays.

Final reserve fuel

For IFR flight, 30 minutes holding at 1 500 ft above the alternate; for VFR flight, 45 minutes at normal cruise speed.

Point of no return

The point from which it is no longer possible to return to the departure aerodrome with the fuel available; it depends on fuel, TAS and fuel flow.

Time of useful consciousness

The period after a decompression during which a pilot can still act effectively; it is about 30 to 60 seconds at FL 350 and 3 to 5 minutes at FL 250.

Somatogravic illusion

An illusion in which forward acceleration is felt as a climb, causing the pilot to push the nose down; it is dangerous during a night take-off or go-around.

Night vision adaptation

Rods need about 30 minutes for full dark adaptation and are most sensitive to blue-green light; off-centre viewing improves detection of dim objects.

QNH and QFE

QNH is the pressure reduced to sea level so the altimeter reads aerodrome elevation; QFE is the pressure at the aerodrome so the altimeter reads zero on the ground.

Clear ice

Clear ice forms from large supercooled droplets between 0 and minus 10 degrees Celsius; it is heavy, hard and difficult to remove.

Cold front characteristics

A cold front has a steep slope, a narrow band of heavy showers, thunderstorms and a sharp wind veer as it passes.

Great circle

The shortest path between two points on a sphere; its track changes continuously and it crosses each meridian at a different angle.

Departure formula

Departure in nautical miles equals change of longitude in minutes multiplied by the cosine of the latitude; one minute of latitude equals one nautical mile.

One-in-sixty rule

A one-degree error over 60 nautical miles produces a one-nautical-mile lateral error; it is used to calculate off-track corrections.

VOR radial

The magnetic bearing from the station to the aircraft, selected with the OBS; the CDI centres when the selected radial matches the aircraft's bearing.

DME slant range

DME measures the slant distance to the station, which exceeds the ground distance; the error is small only when the aircraft is close to the station.

RAIM prediction

Receiver autonomous integrity monitoring checks satellite signals for errors; a prediction is required before an RNP approach to confirm availability.

V1 decision speed

The speed at which a serious failure requires the take-off to be continued; below V1 a rejected take-off is possible.

Emergency descent

Don masks, set 100 percent oxygen, establish the descent speed, silence the cabin altitude warning and descend to 10 000 ft or the minimum safe altitude.

Lift formula

Lift equals one half times density times velocity squared times wing area times lift coefficient; it rises with the square of speed and with the lift coefficient.