MS flareless fittings. Designed primarily for highpressure (3,000 psi) hydraulic systems that may be subjected to severe vibration or fluctuating pressure. Using this type of fitting eliminates all tube flaring, yet provides a safe and strong, dependable tube connection. The fitting consists of three parts: a body, a sleeve, and a nut.

Multiplication. The process of repeated addition.

Negative number. A number that is less than zero.

Nomogram. A graph that usually consists of three sets of data. Knowledge of any two sets of data enables the reader to determine the third set.

Normalizing. The process of heating the part to the proper temperature, holding it at that temperature until it is uniformly heated, and then cooling it in still air.

Nuclear energy. Energy stored in the nucleus of atoms is released during the process of nuclear fission in a nuclear reactor or atomic explosion.

Numerator. The upper part of a fraction (represented by the letter N in N⁄D).

Oblique view. A view that is similar to an isometric view except with two of the three drawing axes always at right angles to each other.

Ohm’s Law. Explains the relationship between voltage, current, and resistance in an electrical circuit, and states that current flow in an electrical circuit is directly proportional to the amount of voltage applied to the circuit.

Ohmmeter. A current measuring instrument that provides its own source (self-excited) of power.

Ohm. The standard unit used to measure resistance.

One-hundred-hour inspection. A complete inspection that is required for all aircraft operated for hire every 100 hours. An annual inspection must be conducted by an A&P mechanic with Inspection Authorization.

Operating center of gravity range. The center of gravity for an aircraft loaded and ready for flight.

Orthographic projection. A method of showing all six possible views of an object: front, top, bottom, rear, right side, and left side.

Outside calipers. Used for measuring outside dimensions, such as the diameter of a piece of round stock.

Parallel circuit. A circuit in which two or more electrical resistances or loads are connected across the same voltage source.

Pascal’s Law. The law that states that pressure applied anywhere to a body of fluid causes a force to be transmitted equally in all directions; the force acts at right angles to any surface in contact with the fluid.