CAAB ATPL Theory flashcards

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

Squawk 7700

A transponder code that signals a general emergency to air traffic control; pilots select it when the aircraft is in immediate danger and require priority assistance.

Right-of-way converging aircraft

When two aircraft of the same category converge at the same altitude, the aircraft on the right has the right of way; the other must give way.

Class C VFR clearance

In ICAO Class C airspace, VFR flights are permitted but require an ATC clearance; IFR flights are separated from all other IFR and VFR traffic.

Certificate of airworthiness

An aircraft engaged in international navigation must carry a valid certificate of airworthiness issued by its state of registry, unless a special permit applies.

Four-stroke engine cycle

A reciprocating engine completes intake, compression, power, and exhaust strokes in four piston movements, requiring two crankshaft revolutions per complete cycle.

Pitot-static airspeed indicator

The airspeed indicator compares total pressure from the pitot tube with static pressure; the difference represents dynamic pressure and is displayed as indicated airspeed.

Hydraulic pressure formula

Pressure in a hydraulic system equals force divided by area (P = F/A); Pascal's law states that pressure applied to a confined fluid is transmitted undiminished throughout.

Turbine engine thrust

Turbine thrust approximately equals mass airflow multiplied by the change in gas velocity, plus a pressure-thrust term from the exhaust nozzle.

Density altitude

Density altitude is pressure altitude corrected for nonstandard temperature; high elevation, high temperature, high humidity, and low pressure increase it and reduce aircraft performance.

V1 decision speed

V1 is the takeoff decision speed: before V1 a rejected takeoff should be initiated, and after V1 the takeoff is normally continued unless the aircraft is unsafe.

Crosswind component formula

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

Load factor stall speed

In a level turn, load factor n equals 1 divided by cosine of bank angle; stall speed increases in proportion to the square root of load factor.

Time of useful consciousness

Time of useful consciousness is the period after exposure to insufficient oxygen before useful performance is lost; it decreases rapidly as cabin altitude increases.

Somatogravic illusion

Somatogravic illusion is a false sensation of pitch during acceleration or deceleration; rapid acceleration can feel like a nose-up attitude and cause a pilot to push forward.

Rods in night vision

Rods are retinal photoreceptors used in dim light; they provide peripheral and motion detection but no color, and dark adaptation can take about 30 minutes.

ISA sea-level values

International Standard Atmosphere sea-level values are 15 degrees Celsius, 1013.25 hectopascals, and a temperature lapse rate of about 1.98 degrees Celsius per 1000 feet.

QNH altimeter setting

QNH is the pressure setting that makes the altimeter indicate elevation above mean sea level at the airport; it is used for terrain clearance in the altimeter setting region.

Advection fog

Advection fog forms when warm, moist air moves over a colder surface and cools to its dew point; it can occur with moderate wind and is common over sea or snow.

Clear ice accretion

Clear ice forms when large supercooled droplets strike an aircraft and freeze slowly, spreading over the surface; it is dense, heavy, and can seriously alter airfoil shape.

Great circle route

A great circle is the shortest path between two points on a sphere; its track changes continuously and appears curved on a Mercator chart except at the equator or meridians.

Magnetic variation east

Easterly magnetic variation means magnetic north lies east of true north; convert magnetic to true by adding easterly variation, and true to magnetic by subtracting it.

VOR radial

A VOR radial is a magnetic bearing extending outward from the station; the cockpit indicator shows whether the aircraft is left or right of the selected radial.

MAYDAY distress call

MAYDAY is the radiotelephony distress signal repeated three times to indicate grave and imminent danger; it requests immediate assistance and has priority over all other communications.

Sterile cockpit rule

The sterile cockpit rule prohibits nonessential conversation and activity during critical phases such as taxi, takeoff, approach, and landing to protect attention and communication.

Emergency descent procedure

After a decompression, pilots don oxygen masks, establish communication, and descend promptly to a cabin altitude where breathing without supplemental oxygen is possible, while turning off course as needed.

Critical angle of attack

The critical angle of attack is the angle at which airflow separates from the wing and lift decreases sharply; a stall occurs at this angle regardless of speed or weight.

Induced drag versus speed

Induced drag decreases as airspeed increases because a given lift is produced with a smaller angle of attack and weaker wingtip vortices; parasite drag increases with speed.

Dihedral effect

Dihedral is the upward angle of the wings; it creates a rolling moment that opposes sideslip and provides lateral stability, especially after a disturbance.

Ground effect

Ground effect occurs when an aircraft flies close to a surface; it reduces wingtip vortices and induced drag, allowing takeoff or landing at a lower speed and shorter distance.

Readback requirement

Pilots must read back ATC clearances and instructions that affect safety, including runway assignments, altitude, heading, frequency, and hold-short instructions, to confirm correct receipt.

PAN PAN urgency call

PAN PAN is the radiotelephony urgency signal repeated three times for a condition concerning aircraft safety but not requiring immediate distress action; it requests priority assistance.

Squawk 7600

Squawk 7600 is the transponder code for radio communication failure; pilots select it and follow published loss-of-communication procedures for the applicable airspace and flight rules.