BDCA ATPL Knowledge Exam flashcards

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

Class A airspace

Controlled airspace in which only IFR flights are permitted and all aircraft require an ATC clearance; VFR is not allowed.

Transition altitude

The altitude at or below which aircraft use altimeter settings referenced to mean sea level; above it, standard pressure setting 1013.25 hPa and flight levels are used.

Semicircular rule

Flight levels are assigned by magnetic track: tracks 000 to 179 degrees use odd levels, tracks 180 to 359 degrees use even levels, separating opposing traffic.

V1 decision speed

The speed at which a failure is recognised and the takeoff can still be safely continued or rejected; below V1 a rejected takeoff is normally possible.

Detonation

Uncontrolled explosive combustion of the fuel-air mixture in the cylinder, producing high pressures and temperatures that can damage the engine.

Constant-speed propeller

A propeller whose blade angle is adjusted by a governor to maintain a selected engine speed despite changes in airspeed and power.

Density altitude

Pressure altitude corrected for temperature and humidity; higher density altitude reduces engine power, lift and propeller efficiency.

Centre of gravity limits

The forward and aft limits within which the aircraft centre of gravity must remain for safe control and stability in all loading conditions.

Crosswind component

The portion of the wind blowing across the runway, calculated as wind speed multiplied by the sine of the angle between wind and runway.

Hypoxia

A condition in which body tissues receive insufficient oxygen; symptoms include euphoria, impaired judgement and cyanosis, worsening rapidly at high altitude.

Somatogravic illusion

A false sensation of pitch caused by linear acceleration or deceleration, leading pilots to misjudge climb or descent without visual reference.

Time of useful consciousness

The period after loss of cabin pressure during which a person can still take effective action before incapacitation; it shortens sharply with increasing altitude.

QNH

The altimeter pressure setting that causes the instrument to indicate altitude above mean sea level when on the ground at the reference point.

Advection fog

Fog formed when warm moist air moves over a colder surface, cooling to its dew point; it can occur with moderate winds.

Clear ice

A dense, transparent airframe ice formed by large supercooled droplets spreading over the surface; it is heavy and difficult to remove.

Great circle

The shortest path between two points on the surface of a sphere; its direction changes continuously along the route.

Variation

The angular difference between true north and magnetic north at a given location, changing slowly over time and shown on charts.

Drift angle

The angle between the aircraft heading and the actual track over the ground, caused by the wind component across the flight path.

V2 takeoff safety speed

The speed to be maintained after takeoff with one engine inoperative, ensuring adequate climb gradient and control until acceleration altitude.

Mayday call

The international distress signal, transmitted three times, indicating grave and imminent danger requiring immediate assistance.

Emergency descent

A rapid descent to a lower altitude after cabin decompression, using maximum rate, turning off track as required and alerting ATC.

Induced drag

Drag caused by the generation of lift, proportional to the square of the lift coefficient and decreasing as airspeed increases.

Critical angle of attack

The angle of attack at which the wing stalls regardless of airspeed, weight or attitude; exceeding it causes airflow separation.

Load factor

The ratio of lift to weight; in a level turn it equals one divided by the cosine of the bank angle, increasing stall speed.

Transponder code 7700

The standard squawk code selected to indicate a general emergency, alerting ATC and triggering alarm on radar displays.

Pan pan call

The urgency signal, transmitted three times, used when an aircraft is in difficulty but not in immediate danger of serious harm.

Readback requirement

Pilots must repeat clearances, runway assignments, altimeter settings, headings and frequencies to confirm correct receipt of instructions.

VOR radial

A magnetic bearing from a VOR station; the cockpit indicator shows deviation from the selected radial and TO or FROM sense.

Glide path

The vertical guidance beam of an ILS, normally set at about three degrees, guiding the aircraft to the touchdown zone.

DME slant range

The line-of-sight distance measured by DME, which exceeds the ground distance when the aircraft is at altitude above the station.

RAIM

Receiver autonomous integrity monitoring, a GNSS function that detects faulty satellite signals and warns the pilot of unreliable position.

Secondary radar

A radar system that interrogates an aircraft transponder and uses the reply to determine identification, range and pressure altitude.