microwave landing system. See MLS.
microwaves. A general classification of electromagnetic radiation having wavelengths between 0.3 and 30
centimeters. These wavelengths correspond to frequencies between one and 100 gigahertz (1 x 109, and
100 x 109 hertz).
Microwave radiation falls between infrared waves and radio waves, and many of the principles which apply to the transmission of light also apply to the transmission of microwave radiation. Microwaves used in communications are transmitted from antennas mounted in dish-shaped reflectors and are concentrated and aimed in much the same way as a beam of light.
MIG welding (metal inert gas welding). A form of electric arc welding in which the electrode is an expendable wire. MIG welding is now called GMA (gas metal arc) welding.
mil. A unit of length equal to 1/1,000 inch (0.001 inch). Mil is short for milli-inch.
mildew. A gray or white fungus growth that forms on organic matter. Mildew forms on cotton and linen aircraft fabric and destroys its strength.
mildewcide. A material used to kill mildew before it destroys organic materials, such as cotton or linen fabric or leather. Cotton and linen fabric are both used to cover aircraft structure, and unless they are protected by a mildewcide, they soon lose their strength. A mildewcide is mixed in the first coat of clear dope applied to these fabrics.
mild steel. Steel containing between 0.05 and 0.25 percent carbon. Mild steel is used for applications where high strength and light weight are not required.