Aviation Maintenance Terms beginning with F

FAA Form 337

This form must be completed when a major repair or alteration is accomplished.

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Ferrous metals

Metals having iron as their principal constituent.

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Force

The intensity of an impetus, or the intensity of an input.

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Foreign object damage (FOD)

Any damage caused by any loose object to aircraft, personnel, or equipment. These loose objects can be anything from broken runway concrete to shop towels and safety wire.

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Fraction

A number written in the form N⁄D in which N is the numerator and D is the denominator. For example, 5⁄16 is a fraction.

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Frequency

The number of cycles (on/off) completed per unit of time. Usually expressed in Hertz.

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Fretting corrosion

Occurs when two mating surfaces, normally at rest with respect to one another, are subject to slight relative motion.

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Friction

The opposition to movement between objects.

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Fuel grade

The rating system used for aviation gasoline. It rates fuel according to its antidetonation characteristics.

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Fuse

A protective device containing a special wire that melts when current exceeds the rated value for a definite period.

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Fuselage stations (FS)

Reference locations, usually given in inches, used to determine forward and aft positions on an aircraft. FS − 0 is the datum

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