Iran CAO ATPL Theory flashcards

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

VFR visibility minima

In controlled airspace, VFR flight requires flight visibility of at least 5 km and distance from cloud of 1500 m horizontally and 300 m vertically, unless a higher minimum is specified by the State.

Semi-circular rule

For IFR flights, magnetic tracks from 000° to 179° use odd flight levels (e.g., FL 090, 110), while tracks from 180° to 359° use even flight levels (e.g., FL 100, 120).

Right-of-way rules

When two aircraft converge, the one with the other on its right has right-of-way. Head-on, both turn right. Overtaking aircraft keeps clear by turning right.

Detonation in piston engines

Detonation is the uncontrolled explosion of the fuel-air mixture after ignition, causing high cylinder pressures and temperatures. It is remedied by reducing power, enriching the mixture, and lowering cylinder head temperature.

N1 and N2

In a turbojet engine, N1 is the rotational speed of the low-pressure compressor (or fan), and N2 is the speed of the high-pressure compressor. They are expressed as percentages of design speed.

Hydraulic accumulator

A hydraulic accumulator stores pressurized fluid to dampen pressure surges, compensate for pump fluctuations, and provide a limited emergency supply of hydraulic pressure in case of pump failure.

Fuel planning reserves

Trip fuel plus contingency fuel (5% or 3% with en-route alternate), alternate fuel, final reserve (30 minutes holding), and taxi fuel must be carried for an IFR flight.

Point of No Return

The PNR is the furthest point from which an aircraft can return to base with the fuel available. Distance = (fuel available × GS out × GS back) / (GS out + GS back).

Equal Time Point

The ETP is the point where the time to fly to either of two airfields is equal. Time to ETP = (total fuel available × GS back) / (GS out + GS back).

Hypoxia symptoms

Hypoxia causes euphoria, impaired judgment, cyanosis, and loss of consciousness. Time of useful consciousness at FL 350 is about 30–60 seconds, so immediate use of oxygen is essential.

Somatogravic illusion

A spatial disorientation illusion in which rapid acceleration is misinterpreted as a climb, and rapid deceleration as a descent. Pilots must rely on flight instruments, not bodily sensations.

Yerkes-Dodson law

Performance increases with arousal up to an optimum point, beyond which it declines. High stress reduces performance, especially on complex tasks.

ISA conditions

International Standard Atmosphere: sea level temperature 15°C, pressure 1013.25 hPa, temperature lapse rate 1.98°C per 1000 ft up to the tropopause at 36,090 ft.

QNH and QFE

QNH is the altimeter setting that causes the altimeter to indicate elevation above mean sea level. QFE causes it to indicate height above a specific reference point, usually the aerodrome.

Clear ice

Clear ice forms from large supercooled water droplets that spread over the surface before freezing, creating a smooth, heavy, and transparent layer that is difficult to remove and seriously affects performance.

Great circle

A great circle is the shortest path between two points on the Earth's surface. On a Mercator chart it appears as a curved line, while a rhumb line is straight but longer.

Magnetic variation

The angle between true north and magnetic north. East variation is subtracted from true heading to obtain magnetic heading; west variation is added (east is least, west is best).

VOR radial

A VOR radial is the magnetic bearing from the station to the aircraft. The CDI shows deviation from the selected radial, and TO/FROM indicates whether the aircraft is flying to or from the station.

ILS glideslope

The ILS glideslope provides vertical guidance, typically on a 3° path, transmitted on frequencies 329–335 MHz. It is paired with the localizer, which provides lateral guidance.

Transponder codes

Squawk 7700 for emergency, 7600 for radio failure, and 7500 for hijack. Mode C reports altitude. These codes alert ATC to the nature of the situation.

Stabilised approach

An approach must be stabilised by 1000 ft in IMC or 500 ft in VMC, with the aircraft on the correct flight path, at the correct speed and configuration, and with a briefed missed approach.

Minimum fuel

A situation where the aircraft's fuel supply may result in landing below final reserve. The pilot must declare MINIMUM FUEL, and ATC will provide priority handling but not emergency status.

Lift formula

Lift = ½ × density × velocity squared × wing area × lift coefficient. The lift coefficient increases with angle of attack up to the critical angle, beyond which the wing stalls.

Load factor in turns

In a level turn, load factor n = 1 / cos(bank angle). Stall speed increases by the square root of n. At 60° bank, load factor is 2 and stall speed increases by 41%.

Critical Mach number

The free-stream Mach number at which airflow over some part of the aircraft first reaches the speed of sound, creating shock waves and increasing drag. Swept wings increase the critical Mach number.

Phonetic alphabet

The ICAO phonetic alphabet assigns words to letters: Alfa, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliett, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu.

Readback requirements

Pilots must read back clearances and instructions involving runway, altitude, heading, speed, frequency, and QNH. ATC must correct any incorrect readback to ensure safety.

Centre of gravity

CG = total moment / total mass. Forward CG limits ensure elevator authority for rotation and flare; aft CG limits ensure longitudinal stability. Both must be respected for safe flight.

Maximum zero fuel mass

MZFM is the maximum mass of the aircraft without usable fuel. It limits the payload that can be carried, ensuring structural limits and performance are not exceeded.

V1 decision speed

V1 is the speed at which the pilot must decide to continue the takeoff or reject it. It ensures the aircraft can stop within the accelerate-stop distance or continue safely with one engine failed.

Service ceiling

The altitude at which an aircraft's maximum rate of climb is 100 ft/min. The absolute ceiling is the altitude where the climb rate becomes zero.

Altimeter temperature error

When temperature is higher than ISA, the altimeter underreads, indicating an altitude lower than actual. When colder than ISA, it overreads. This affects terrain clearance and approach minima.