Aviation Maintenance Terms beginning with O

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

The standard unit used to measure resistance.

Ohmmeter

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

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.

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