ICAA PPL Theory flashcards

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

VMC minima Class G below 900 m

In Class G at or below 900 m AMSL, VFR requires 5 km flight visibility, clear of cloud and in sight of the surface.

Emergency transponder codes

Squawk 7500 for unlawful interference, 7600 for radio failure and 7700 for general emergency; 121.5 MHz is the emergency frequency.

Right-of-way converging aircraft

When two aircraft converge, the one on the right has right of way; power-driven aircraft give way to gliders, airships and balloons, and all give way to landing aircraft.

Four-stroke engine cycle

The cycle is induction, compression, combustion (power) and exhaust; the camshaft turns at half crankshaft speed, so each cylinder fires once every two revolutions.

Carburettor icing temperature range

Carburettor icing is most likely with ambient temperatures between about -5 °C and +15 °C and high humidity; applying carburettor heat causes a temporary RPM drop before recovery.

Static port blockage in climb

If the static port is blocked, trapped pressure remains constant; in a climb the airspeed indicator reads higher than actual and the altimeter under-reads.

Magneto check at run-up

Select each magneto in turn and note the RPM drop; the aircraft flight manual specifies the maximum drop and differential, typically 150 RPM and 50 RPM respectively.

Density altitude formula

Density altitude equals pressure altitude plus 120 times the difference between outside air temperature and ISA temperature at that pressure altitude.

Crosswind component formula

Crosswind component equals wind speed multiplied by the sine of the angle between wind and runway; headwind equals wind speed times the cosine of that angle.

Centre of gravity calculation

Multiply each weight by its arm to get moments, sum the moments, then divide by total weight; the result must lie within the forward and aft CG limits.

Cold temperature altimeter error

Flying from warm air into colder air without resetting the altimeter causes it to read higher than the true altitude, reducing obstacle clearance.

Time of useful consciousness

At 25,000 ft time of useful consciousness is about 3 to 5 minutes; at 35,000 ft it falls to roughly 30 to 60 seconds.

Somatogravic illusion

During acceleration, the otolith organs signal a false climb; the pilot may push the nose down, so instrument indications must be trusted over sensations.

Night vision and rods

Rods provide night vision, adapt over 20 to 30 minutes and are degraded by smoking, alcohol and bright light; off-centre viewing improves detection of dim objects.

Hyperventilation treatment

Hyperventilation causes dizziness, tingling and visual disturbance; slow the breathing rate, but use supplemental oxygen first if hypoxia cannot be excluded.

ISA sea-level values

International Standard Atmosphere sea-level values are 15 °C and 1013.25 hPa, with a lapse rate of about 2 °C per 1,000 ft up to the tropopause.

Pressure altitude lapse

Near sea level, pressure changes by about 1 hPa per 30 ft; the altimeter reads high when flying towards lower pressure without resetting the subscale.

Cloud base estimate

Cloud base in feet is approximately the temperature-dewpoint spread in degrees Celsius multiplied by 400; a small spread indicates a low cloud base.

Warm front characteristics

At a warm front, warm air overruns cold air, producing a long period of lowering cloud, steady rain and smooth air, often with reduced visibility.

Structural icing range

Structural icing occurs roughly between 0 °C and -20 °C in visible moisture; clear ice forms from large supercooled droplets, rime ice from small droplets.

Great circle versus rhumb line

A great circle is the shortest path over the Earth's surface; a rhumb line maintains a constant track but is longer except along the equator or a meridian.

Latitude and longitude distance

One minute of latitude equals 1 nautical mile; one minute of longitude equals 1 nautical mile multiplied by the cosine of the latitude.

One-in-sixty rule

A one-degree track error over 60 nautical miles produces a one nautical mile offset; this rule gives quick heading and closing-angle corrections.

Magnetic variation rule

East variation is subtracted from true direction to obtain magnetic direction (east is least); west variation is added. Deviation is aircraft-specific.

TAS rough estimate

True airspeed is approximately indicated airspeed multiplied by one plus 0.02 times altitude in thousands of feet; use a navigation computer for accuracy.

Wake turbulence avoidance

Land beyond the preceding aircraft's touchdown point and depart before its rotation point; vortices sink and drift with the wind.

Engine failure after take-off

Lower the nose to maintain best glide speed, select a landing area within reach, and attempt a restart only if altitude and time allow.

Radio failure in VMC

In visual conditions, continue under VFR, land at the nearest suitable aerodrome and report arrival; in IMC follow the published lost-communication procedure.

Lift equation

Lift equals half the air density times velocity squared times wing area times lift coefficient; doubling speed quadruples lift at constant angle of attack.

Stall speed and load factor

Stall speed increases with the square root of load factor; at 2 g the stall speed rises by about 41 percent compared with straight-and-level flight.

Load factor in level turn

Load factor equals one divided by the cosine of the bank angle; at 60 degrees bank the load factor is 2 and the stall speed increases accordingly.

Induced versus parasite drag

Induced drag decreases with speed while parasite drag increases with the square of speed; total drag is lowest where the two are equal, giving best glide.