Profile drag, also known as pressure drag or form drag, is the drag caused by the separation of the boundary layer from a surface and the wake created by that separation.

It is primarily dependent upon the shape of the object and increases directly with speed as the faster an aircraft moves the more air molecules collide with it.

V1 is the decision speed (sometimes referred to as critical engine speed or critical engine failure speed) by which any decision to reject a takeoff must be made.

V2 is the takeoff safety speed which must be attained at the 35 ft height at the end of the required runway distance. This is essentially the best one-engine inoperative angle of climb speed for the airplane and is a minimum speed for flight in that condition until at least 400 ft above the ground. V2 shall be at least 1.1 times VMCA, and no less than 1.2 times VS.

Vr is defined as the speed at which the rotation of the aircraft should be initiated to takeoff attitude.

VMCA is the minimum control speed in the air and is defined as the minimum speed, whilst in the air, that directional control can be maintained with one engine inoperative (critical engine on two engine aerolanes), operating engine(s) at takeoff power and a maximum of 5 degrees of bank towards the good engine(s).

VMCG is the minimum control speed on the ground and is defined as the minimum speed, whilst on the ground, that directional control can be maintained, using only aerodynamic controls, with one engine inoperative (critical engine on two engine airplanes) and takeoff power applied on the other engine(s).

a line extending from the leading edge to the trailing edge equidistent from the upper and lower surface of the aerofoil.

-35°C

The angle between the chordline and the incoming airflow.

A line of shortest distance between two points on a sphere.

By using the formula: Range (nm) = 1.23(√H1 + √H2)

H1=height of transmitter (feet)

H2=height of receiver (feet)

Cumulonimbus clouds

Thunderstorms

Virga

A line on a meteorologic chart that joins places of equal sea level pressure (QNH).