ATPL Operational Procedures, Navigation, Instrumentation, Performance, Air Law, and Meteorology

Essential vocabulary terms and standardized definitions for ATPL candidates covering Operational Procedures, General Navigation, Instrumentation, Aircraft Performance, Air Law, and Meteorology.

RNP Type

A containment value defined in Annex 6, expressed as a distance in nautical miles from the intended position within which flights remain for at least $95\%$ of the total flying time.

Decision Height (DH)

A specified height used during a precision approach at which a missed approach must be initiated if the required visual reference has not been established.

Category I Precision Approach (CAT I)

A precision instrument approach with a decision height equal to at least $200\,\text{ft}$ and a runway visual range of at least $550\,\text{m}$.

Category II Precision Approach (CAT II)

A precision instrument approach with a decision height not lower than $100\,\text{ft}$.

Wind Shear

A large variation in vertical or horizontal wind velocity and/or wind direction over a short distance, which can occur at any altitude in both planes.

Contaminated Runway

A runway whose surface is covered by more than $25\%$ with compacted snow, standing water, slush, or ice.

Damp Runway

A runway surface that is not dry, but where surface moisture does not give it a shiny appearance.

Dynamic Hydroplaning

A form of hydroplaning primarily caused by the depth of standing water on the runway, lifting the aircraft tires off the pavement.

Viscous Hydroplaning

Hydroplaning occurring primarily on very smooth and dirty runway surfaces covered with a thin film of water, frequently in the touchdown zone.

Magnetic Variation

The angular difference measured between True North and Magnetic North.

Compass Deviation

The angular difference measured between Magnetic North and Compass North.

Time of Useful Consciousness (TUC)

The interval between the interruption of oxygen supply and the loss of useful mental and physical capability, which is approximately $12\,\text{seconds}$ at an altitude of $40\,000\,\text{ft}$.

Total Air Temperature (TAT)

The air temperature resulting from the aircraft's motion through the air, measured by a temperature probe.

Static Air Temperature (SAT)

The undisturbed ambient outside air temperature.

QNH

The altimeter subscale setting that causes the altimeter to indicate the official aerodrome elevation when on the apron.

Fail-Operational Flight Control System

An automatic flight control system designed such that, following any single failure, the approach, flare, and landing can still be completed automatically.

Fail-Passive Flight Control System

A flight control system wherein a failure causes no significant out-of-trim condition or deviation of flight path or attitude, but automatic landing cannot be completed.

Mach Trim

An automatic system that compensates for the rearward movement of the aerodynamic center at high Mach numbers by adjusting the horizontal stabilizer nose-up.

Stopway

A rectangular area beyond the end of $\text{TORA}$ prepared to support the aeroplane mass during an abandoned take-off, increasing only the $\text{ASDA}$.

Clearway

A defined rectangular area on the ground or water selected or prepared as a suitable area over which an aeroplane may make a portion of its initial climb to a specified height.

Balanced Field Length

A runway configuration where the Accelerate-Stop Distance Available ($\text{ASDA}$) is equal to the Take-Off Distance Available ($\text{TODA}$).

Take-off Decision Speed ($V_1$)

The airspeed on the ground at which the pilot is assumed to have made the decision to continue or discontinue the take-off.

Rotation Speed ($V_R$)

The indicated airspeed at which rotation to the lift-off attitude is initiated by the pilot.

Take-off Safety Speed ($V_2$)

The target climb speed maintained during initial take-off climb following an engine failure.

Minimum Control Speed on the Ground ($V_{MCG}$)

The minimum speed during the take-off run at which directional control can be safely maintained using primary aerodynamic flight controls only.

Absolute Ceiling

The theoretical altitude at which the maximum achievable rate of climb drops to $0\,\text{ft/min}$.

Service Ceiling

The altitude during all-engines-operating climb where the maximum rate of climb drops to $100\,\text{ft/min}$.

Barrette

Three or more ground lights closely spaced together transversely so that they appear from a distance as a continuous horizontal bar of light.

First Freedom of the Air

The legal right of an airline to overfly the territory of a foreign country without landing.

Second Freedom of the Air

The legal right of an airline to land in a foreign country solely for a technical stop, such as refueling, without taking on or discharging commercial traffic.

Non-Directional Beacon (NDB)

A ground-based radio beacon that transmits omnidirectional LF/MF signals on carrier frequencies allocated between $190\,\text{kHz}$ and $1750\,\text{kHz}$.

Advection

The horizontal movement and transfer of air and its thermodynamic properties across the Earth's surface.

Isotachs

Lines drawn on an aeronautical weather or upper-air chart connecting points of equal wind speed.

Dry Adiabatic Lapse Rate (DALR)

The rate at which unsaturated dry air cools adiabatically as it rises, equal to $3.0^\circ\text{C}/1000\,\text{ft}$.

Clear Ice

Heavy, glossy, and solid ice formed when large supercooled water droplets hit the airframe and spread out before slowly freezing at temperatures just below freezing.