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Glossary

PHAK Glossary: F

35 entries, reproduced verbatim from the Glossary of the Pilot’s Handbook of Aeronautical Knowledge, FAA-H-8083-25C (July 2023).

False horizon

Inaccurate visual information for aligning the aircraft, caused by various natural and geometric formations that disorient the pilot from the actual horizon.

PHAK Glossary, page G-11

Federal airways

Class E airspace areas that extend upward from 1,200 feet to, but not including, 18,000 feet MSL, unless otherwise specified.

PHAK Glossary, page G-12

Feeder facilities

Used by ATC to direct aircraft to intervening fixes between the en route structure and the initial approach fix.

PHAK Glossary, page G-12

Final approach

Part of an instrument approach procedure in which alignment and descent for landing are accomplished.

PHAK Glossary, page G-12

Final approach fix (FAF)

The fix from which the IFR final approach to an airport is executed, and which identifies the beginning of the final approach segment. An FAF is designated on government charts by a Maltese cross symbol for nonprecision approaches, and a lightning bolt symbol for precision approaches.

PHAK Glossary, page G-12

Fixed-pitch propellers

Propellers with fixed blade angles. Fixed-pitch propellers are designed as climb propellers, cruise propellers, or standard propellers.

PHAK Glossary, page G-12

Fixed slot

A fixed, nozzle shaped opening near the leading edge of a wing that ducts air onto the top surface of the wing. Its purpose is to increase lift at higher angles of attack.

PHAK Glossary, page G-12

Flameout

A condition in the operation of a gas turbine engine in which the fire in the engine goes out due to either too much or too little fuel sprayed into the combustors.

PHAK Glossary, page G-12

Flaps

Hinged portion of the trailing edge between the ailerons and fuselage. In some aircraft ailerons and flaps are interconnected to produce full-span “flaperons.” In either case, flaps change the lift and drag on the wing.

PHAK Glossary, page G-12

Floor load limit

The maximum weight the floor can sustain per square inch/foot as provided by the manufacturer.

PHAK Glossary, page G-12

Flight configurations

Adjusting the aircraft control surfaces (including flaps and landing gear) in a manner that will achieve a specified attitude.

PHAK Glossary, page G-12

Flight director indicator (FDI)

One of the major components of a flight director system, it provides steering commands that the pilot (or the autopilot, if coupled) follows.

PHAK Glossary, page G-12

Flight level (FL)

A measure of altitude (in hundreds of feet) used by aircraft flying above 18,000 feet with the altimeter set at 29.92 "Hg.

PHAK Glossary, page G-12

Flight management system (FMS)

Provides pilot and crew with highly accurate and automatic long-range navigation capability, blending available inputs from long- and shortrange sensors.

PHAK Glossary, page G-12

Flight path

The line, course, or track along which an aircraft is flying or is intended to be flown.

PHAK Glossary, page G-12

Flight patterns

Basic maneuvers, flown by reference to the instruments rather than outside visual cues, for the purpose of practicing basic attitude flying. The patterns simulate maneuvers encountered on instrument flights such as holding patterns, procedure turns, and approaches.

PHAK Glossary, page G-12

Flight strips

Paper strips containing instrument flight information, used by ATC when processing flight plans.

PHAK Glossary, page G-12

Fog

Cloud consisting of numerous minute water droplets and based at the surface; droplets are small enough to be suspended in the earth’s atmosphere indefinitely. (Unlike drizzle, it does not fall to the surface. Fog differs from a cloud only in that a cloud is not based at the surface, and is distinguished from haze by its wetness and gray color.)

PHAK Glossary, page G-12

Force (F)

The energy applied to an object that attempts to cause the object to change its direction, speed, or motion. In aerodynamics, it is expressed as F, T (thrust), L (lift), W (weight), or D (drag), usually in pounds.

PHAK Glossary, page G-12

Foreign object damage (FOD)

Damage to a gas turbine engine caused by some object being sucked into the engine while it is running. Debris from runways or taxiways can cause foreign object damage during ground operations, and the ingestion of ice and birds can cause FOD in flight.

PHAK Glossary, page G-12

Frise-type aileron

Aileron having the nose portion projecting ahead of the hinge line. When the trailing edge of the aileron moves up, the nose projects below the wing’s lower surface and produces some parasite drag, decreasing the amount of adverse yaw.

PHAK Glossary, page G-12

Frost

Ice crystal deposits formed by sublimation when temperature and dewpoint are below freezing.

PHAK Glossary, page G-13

Fuel load

The expendable part of the load of the airplane. It includes only usable fuel, not fuel required to fill the lines or that which remains trapped in the tank sumps.

PHAK Glossary, page G-13

Fundamental skills

Pilot skills of instrument cross-check, instrument interpretation, and aircraft control.

PHAK Glossary, page G-13

Fuselage

The section of the airplane that consists of the cabin and/or cockpit, containing seats for the occupants and the controls for the airplane.

PHAK Glossary, page G-13

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The Private Pilot Quick-Review Study Guide covers this in the chapters these terms come up in. It is in CFI review and not on sale yet; the guide page has the list for launch notes.

Source. Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Glossary, FAA-H-8083-25C (July 2023), pages G-1 to G-36, reproduced verbatim from the FAA’s PDF (https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/phak; SHA-256 begins 247929cace0ab56b). The PDF’s line breaks were re-joined into one paragraph per entry; no word was changed. A United States Government work. Check the current handbook before you rely on an entry here.