Karman vortex street
Two parallel rows of alternately shed vortices along the wake of an obstacle.

Katabatic winds.
A wind produced by the flow of cold, dense air down a slope in an area subject to radiational cooling. Mountain winds are the most common form of katabatic winds.

KEEL
A strong longitudinal member at the bottom of a float or hull that helps guide the seaplane through the water, and, in the case of floats, supports the weight of the seaplane on land.

Kelvin-Helmholtz (K-H) wave
A wave occurring in an atmosphere with a stable lapse rate of temperature. K-H waves derive their energy from strong vertical wind shear.

Kevlar®
A registered trademark for a DuPont Corporation product, a synthetic fiber created in 1965 which has a strength factor 5 times that of steel. Frequently used in balloon systems for suspension cables and control lines of various types. Generally, Kevlar® is used for the core of a suspension line, and will have a cover or sheath over the core, as Kevlar® is ultraviolet light sensitive.

KIAS
Knots indicated airspeed.

Kinesthesia
The sensing of movements by feel.

Kinetic energy.
Energy due to motion, defined as one half mass times velocity squared.

King post
The post on top of the wing which is attached to
the keel that holds used for the ground wires which hold up
the wings on the ground and during negative loads during
flight.

KNOT
A unit of speed equal to one nautical mile per hour.

Knowledge.
Information that humans are consciously aware of and can articulate.

KNOWN TRAFFIC
With respect to ATC clearances, means aircraft whose altitude, position, and intentions are known to ATC.

Kollsman window.
A barometric scale window of a sensitive altimeter used to adjust the altitude for the altimeter setting.