Glossary of aviation
Terms
and abreviations.
DEADSTICK - Descending flight with engine and propeller stopped.
DECALAGE - The difference in angular settings [Angles of
Attack] of the wings of a biplane or multiplane.
DECISION HEIGHT - With respect to the operation of aircraft,
the height at which point a decision must be made during an
instrument approach to either continue the approach or to
execute a missed approach [abort].
DELTA-WING - A triangularly-shaped aircraft wing having a
low aspect ratio, a sharply-tapered leading edge, a straight
trailing edge, and a pointed tip.
DEPARTURE CONTROL SEE RADIO NAVIGATION
DEPARTURE STALL - A stall in the takeoff configuration with
power.
DEVIATION (MAGNETIC) - The error of a Magnetic Compass due
to inherent magnetic influences in the structure and equipment
of an aircraft.
DEWIZ SEE AIR DEFENSE IDENTIFICATION ZONE
DIHEDRAL - The acute angle, usually upward, between the wing
of an airplane and a horizontal cross-section line. Opposite
of ANHEDRAL.
DIRECTIONAL GYRO - A panel instrument providing a gyroscopic
reading of an aircraft's compass heading.
DIRIGIBLE - A lighter-than-air craft capable of being propelled
and steered for controlled flight. Latin: dirigo,to steer.
DME - Distance Measuring Equipment, a radio navigation device
that determines an aircraft's distance from a given ground
station, as well as its groundspeed and time to/from the station.
DORSAL FIN - A lateral fin/rudder extension on the top of
a fuselage.
DOWNWASH - The air deflected perpendicular to the direction
of movement of an airfoil.
DRAG - The resisting force exerted on an aircraft in its
line of flight opposite in direction to its motion. Compare
THRUST.
DRAG WIRE - A wire designed to resist DRAG forces, usually
running from a forward inboard point to an outboard aft point.
DRIFT - The angle between the heading of an aircraft and
its Track, or flight path, over the ground as affected by
winds.
DRY WEIGHT - The weight of an engine exclusive of any fuel,
oil, and coolant.
DURAL - Originally a tradename for a wrought aluminum-copper
alloy created by Bausch Machine Tool Co, now fallen into generic
use as any aluminum alloy containing 3.0-4.5% copper, 0.4-1.0%
magnesium, and 0.1-0.7% manganese. Alcoa's version is commonly
referred to as "Duraluminum," popularly used in
aircaft manufacture.
EARTH-INDUCTOR COMPASS - One whose indications depend on
the current generated in a coil revolving in the earth's magnetic
field.
ELEPHANT EAR - (1) An air intake characterized by twin inlets,
one on each side of the fuselage. (2) A type of balanced aileron
in which the outer edges are noticeably larger than the control
itself. See BALANCED CONTROL SURFACE and example Travel Air
4000.
ELEVATOR - The movable part of a horizontal airfoil which
controls the pitch of an aircraft; the fixed part being the
STABILIZER.
ELEVON - A hinged device on the rear portion of an aircraft
wing combining the functions of an elevator and an aileron.
Usually found on delta-wing aircraft, it can be moved in the
same direction on either side of the aircraft to obtain longitudinal
control, or differentially to obtain lateral control. Also
see FLAPERON.
ELT - Emergency Locator Transmitter
EMPENNAGE - An aircraft's tail group, includes rudder and
fin, and stabilizer and elevator. Old French: empenner,to
feather an arrow, from Latin penna, feather. Other words derived
from the same root are panache, pen, pin, pinnacle, and pennant.
EN ROUTE AIR TRAFFIC CONTROL SERVICES - Air traffic control
services provided aircraft on IFR flight plans, generally
by centers, when these aircraft are operating between departure
and destination terminal areas. When equipment, capabilities,
and controller workload permit, certain advisory/assistance
services may be provided to VFR aircraft.
ETA - Estimated Time of Arrival.
ETD - Estimated Time of Departure.
FAIRING - An added streamlining structure or auxiliary member,
most often of light metal, whose only purpose is to reduce
drag. Fairings are not load-bearing and, therefore, are not
meant to carry any principal air loads placed on the airplane
structure.
FBO - Fixed-Base Operator, a commercial operator supplying
fuel, maintenance, flight training, and other services at
an airport.
FAN MARKER SEE RADIO NAVIGATION
FEATHERING - In the event of engine failure, the process
of adjusting a controllable-pitch propeller to a pitch position
where the blade angle is about 90° to the plane of rotation
in order to stop windmilling.
FEDERAL AIR REGULATION (FAR)
FAR Part 91 - General Aviation (portions apply to all operators)
FAR Part 103 - Ultralight Vehicles
FAR Part 105 - Parachute Jumping
FAR Part 108 - Airplane Operator Security
FAR Part 119 - Certification: Air Carriers and Commercial
Operators
FAR Part 121 - Domestic, Flag, and Supplemental Air Carriers
and Commercial Operators of Large Aircraft
FAR Part 123 - Travel Clubs
FAR Part 125 - US Civil Airplanes, seating 20 or more passengers
or a maximum payload capacity 6,000# or more
FAR Part 127 - Air Carriers using helicopters for scheduled
interstate flights (within the 48 contiguous states)
FAR Part 129 - Foreign Air Carrier and Foreign Operators of
US registered aircraft engaged in common carriage
FAR Part 133 - Rotorcraft External Load Operations
FAR Part 135 - Air Taxi Operators and Commercial Operators
FAR Part 137 - Agricultural Aircraft Operations
FAR Part 141 - Pilot School
FERRY FLIGHT - A flight for the purpose of (1) returning an
aircraft to base; (2) delivering an aircraft from one location
to another; (3) moving an aircraft to and from a maintenance
base. Ferry flights, under certain conditions, may be conducted
under terms in a special flight permit.
FIN - The fixed part of a vertical airfoil that controls
the yaw of an aircraft; the movable part being the RUDDER.
Sometime referred to as Vertical Stabilizer.
FIREWALL - A fire-resistant bulkhead that isolates the engine
from other parts of an airplane's structure.
FISHTAILING - A rudder-controlled side-to-side [yawing] motion
to reduce air speed, generally prior to landing.
FIVE-BY-FIVE (5x5) - In radio jargon, affirms that a radioed
transmission was received clear and loud. Rated one to five,
with the first figure for clearness and the second second
for loudness.
FLAP - A movable, usually hinged AIRFOIL set in the trailing
edge of an aircraft wing, designed to increase LIFT or DRAG
by changing the CAMBER of the wing or used to slow an aircraft
during landing by increasing lift. Also see FOWLER FLAP, SLOTTED
FLAP, and SPLIT FLAP.
FLAPERON - A control surface combining the functions of a
FLAP and an AILERON.
FLARE - A maneuver performed moments before landing in which
the nose of an aircraft is pitched up to minimize the touchdown
rate of speed.
FLIGHT ENVELOPE - An aircraft's performance limits, specifically
the curves of speed plotted against other variables to indicate
the limits of speed, altitude, and acceleration that a particular
aircraft can not safely exceed.
FLIGHT LEVEL (FL) - A level of constant atmospheric pressure
related to a reference datum of 29.92 inches of mercury. Each
is stated in three digits that represent hundreds of feet—flight
level 250 represents a barometric altimeter indication of
25,000', flight level 255 an indication of 25,500'.
FLIGHT PLAN - Specified information relating to the intended
flight of an aircraft that is filed orally or in writing with
an FSS or an ATC facility.
FLIGHT SERVICE STATION (FSS) - Air traffic facilities which
provide pilot briefing, enroute communications and VFR search
and rescue services, assist lost aircraft and aircraft in
emergency situations, relay ATC clearances, originate Notices
to Airmen, broadcast aviation weather and NAS information,
receive and process IFR flight plans, and monitor NAVAIDs.
In addition, at selected locations, FSSs provide Enroute Flight
Advisory Service (Flight Watch), take weather observations,
issue airport advisories, and advise Customs and Immigration
of transborder flights.
FLOATPLANE - A water-based aircraft with one or more mounted
pontoons, as differentiated from a hulled SEAPLANE or Flying
Boat, but sometimes used generically.
FLYING WIRES - Interplane bracing wires that help support
wingloads when the plane is in flight. Direction of travel
is upward and outward from the fuselage to the interplane
struts. Also known as LIFT WIRES, the opposite of LANDING
WIRES.
FOWLER FLAP - Trademark name of a split-flap attached to
a wing through a system of tracks and rollers to roll the
flap backward and downward, increasing the wing area.
FRISE AILERON - A type of aileron that has a beveled leading
edge projecting beyond its inset hinges. When lowered, it
forms an extension of the wing surface; when raised, its nose
protrudes below the wing, increasing DRAG and reducing YAW.
Named after its inventor, British engineer Leslie George Frise.
FSS SEE FLIGHT SERVICE STATION
FUSELAGE - An aircraft's main body structure housing the
flight crew, passengers, and cargo and to which the wings,
tail and, in most single-engined airplanes, engine are attached.
French: fuselé, tapering.
Paragliding Spain Center
