Aeronautical Terms beginning with L
Landing Distance Available (LDA)
ICAO defines LDA as the length of runway,which is declared available and suitable for the ground run of an aeroplane landing.
Lateral Navigation (LNAV)
Azimuth navigation, without positive vertical guidance. This type of navigation is associated with nonprecision approach procedures or en route.
Local Area Augmentation System (LAAS)
LAAS further increases the accuracy of GPS and improves signal integrity warnings.
Localizer Performance with Vertical Guidance (LPV)
LPV is one of the four lines of approach minimums found on an RNAV (GPS) approach chart. Lateral guidance accuracy is equivalent to a localizer. The HAT is published as a DA since it uses an electronic glide path that is not dependent on any ground equipment or barometric aiding and may be as low as 200 feet and 1/2SM visibility depending on the airport terrain and infrastructure. WAAS avionics approved for LPV is required. Baro-VNAV is not authorized to fly the LPV line of minimums on a RNAV (GPS) procedure since it uses an internally generated descent path that is subject to cold temperature effects and incorrect altimeter settings.
Loss of Separation
An occurrence or operation that results in less than prescribed separation between aircraft,or between an aircraft and a vehicle,pedestrian, or object.
LPV
See Localizer Performance with Vertical Guidence
Lateral Axis
An imaginary line passing through the center of gravity of an airplane and extending across the airplane from wingtip to wingtip.
Lateral Stability (Rolling)
The stability about the longitudinal axis of an aircraft. Rolling stability or the ability of an airplane to return to level flight due to a disturbance that causes one of the wings to drop.
Lead-Acid Battery
A commonly used secondary cell having lead as its negative plate and lead peroxide as its positive plate. Sulfuric acid and water serve as the electrolyte.
Leading Edge
The part of an airfoil that meets the airflow first.
Leading Edge Devices
High lift devices which are found on the leading edge of the airfoil. The most common types are fixed slots, movable slats, and leading edge flaps.
Leading Edge Flap
A portion of the leading edge of an airplane wing that folds downward to increase the camber, lift, and drag of the wing. The leading-edge flaps are extended for takeoffs and landings to increase the amount of aerodynamic lift that is produced at any given airspeed.
Licensed Empty Weight
The empty weight that consists of the airframe, engine(s), unusable fuel, and undrainable oil plus standard and optional equipment as specified in the equipment list. Some manufacturers used this term prior to GAMA standardization.
Lift
One of the four main forces acting on an aircraft. On a fixed-wing aircraft, an upward force created by the effect of airflow as it passes over and under the wing.
Lift Coefficient
A coefficient representing the lift of a given airfoil. Lift coefficient is obtained by dividing the lift by the free-stream dynamic pressure and the representative area under consideration.
Lift-Off
The act of becoming airborne as a result of the wings lifting the airplane off the ground, or the pilot rotating the nose up, increasing the angle of attack to start a climb.
Lift/Drag Ratio
The efficiency of an airfoil section. It is the ratio of the coefficient of lift to the coefficient of drag for any given angle of attack.
Limit Load Factor
Amount of stress, or load factor, that an aircraft can withstand before structural damage or failure occurs.
Load Factor
The ratio of the load supported by the airplane’s wings to the actual weight of the aircraft and its contents. Also referred to as G-loading.
Longitudinal Axis
An imaginary line through an aircraft from nose to tail, passing through its center of gravity. The longitudinal axis is also called the roll axis of the aircraft. Movement of the ailerons rotates an airplane about its longitudinal axis.
Longitudinal Stability (Pitching)
Stability about the lateral axis. A desirable characteristic of an airplane whereby it tends to return to its trimmed angle of attack after displacement.
LAAS
See local area augmentation system.
Lag
The delay that occurs before an instrument needle attains a stable indication.
Land as soon as possible
ATC instruction to pilot. Land without delay at the nearest suitable area, such as an open field, at which a safe approach and landing is assured.
Land as soon as practical
ATC instruction to pilot. The landing site and duration of flight are at the discretion of the pilot. Extended flight beyond the nearest approved landing area is not recommended.
Land immediately
ATC instruction to pilot. The urgency of the landing is paramount. The primary consideration is to ensure the survival of the occupants. Landing in trees, water, or other unsafe areas should be considered only as a last resort.
LDA
See localizer-type directional aid.
Lead radial
The radial at which the turn from the DME arc to the inbound course is started.
Leans, the
A physical sensation caused by an abrupt correction of a banked attitude entered too slowly to stimulate the motion sensing system in the inner ear. The abrupt correction can create the illusion of banking in the opposite direction.
Lift
A component of the total aerodynamic force on an airfoil and acts perpendicular to the relative wind.
Lines of flux
Invisible lines of magnetic force passing between the poles of a magnet.
L/MF
See low or medium frequency.
LMM
See locator middle marker.
Load factor
The ratio of a specified load to the total weight of the aircraft. The specified load is expressed in terms of any of the following: aerodynamic forces, inertial forces, or ground or water reactions.
Loadmeter
A type of ammeter installed between the generator output and the main bus in an aircraft electrical system.
LOC
See localizer.
Local area augmentation system (LAAS)
A differential global positioning system (DGPS) that improves the accuracy of the system by determining position error from the GPS satellites, then transmitting the error, or corrective factors, to the airborne GPS receiver.
Localizer (LOC)
The portion of an ILS that gives left/right guidance information down the centerline of the instrument runway for final approach.
Localizer-type directional aid (LDA)
A NAVAID used for nonprecision instrument approaches with utility and accuracy comparable to a localizer but which is not a part of a complete ILS and is not aligned with the runway. Some LDAs are equipped with a glide slope.
Locator middle marker (LMM)
Nondirectional radio beacon (NDB) compass locator, collocated with a middle marker (MM).
Locator outer marker (LOM)
NDB compass locator, collocated with an outer marker (OM).
LOM
See locator outer marker.
Long range navigation (LORAN)
An electronic navigational system by which hyperbolic lines of position are determined by measuring the difference in the time of reception of synchronized pulse signals from two fixed transmitters. LORAN A operates in the 1750 to 1950 kHz frequency band. LORAN C and D operate in the 100 to 110 kHz frequency band.
LORAN
See long range navigation.
Low or medium frequency
A frequency range between 190-535 kHz with the medium frequency above 300 kHz. Generally associated with nondirectional beacons transmitting a continuous carrier with either a 400 or 1,020 Hz modulation.
Lubber line
The reference line used in a magnetic compass or heading indicator.
Lack of common experience
In communication, a difficulty which arises because words have different meanings for the source and the receiver of information due to their differing backgrounds.
Lead-off question
In the guided discussion method, a question used by an instructor to open up an area for discussion and get the discussion started.
Learning
A change in behavior as a result of experience.
Learning plateau
A learning phenomenon where progress appears to cease or slow down for a significant period of time before once again increasing.
Learning style
Preferred way(s) by which people learn. Common learning styles include visual, auditory, and kinesthetic, or tactile (hands on). Learning skills can be loosely grouped into physical and cognitive styles.
Learning theory
A body of principles advocated by psychologists and educators to explain how people acquire skills, knowledge, and attitudes.
Lecture method
An educational presentation usually delivered by an instructor to a group of students with the use of instructional aids and training devices. Lectures are useful for the presentation of new material, summarizing ideas, and showing relationships between theory and practice.
Lesson plan
An organized outline for a single instructional period. It is a necessary guide for the instructor in that it tells what to do, in what order to do it, and what procedure to use in teaching the material of a lesson.
Link
On a website, an external web location that can be accessed by merely clicking on words identifying the new site. They are usually identified by a different color type, underlining, or a button (picture or icon) indicating access to a new site.
Long-term memory
The portion of the brain that stores information that has been determined to be of sufficient value to be retained. In order for it to be retained in longterm memory, it must have been processed or coded in the working memory.
Land Breeze
A coastal breeze flowing from land to sea caused by temperature differences when the sea surface is warmer than the adjacent land. The land breeze usually occurs at night and alternates with the sea breeze that blows in the opposite direction by day.
Lateral Axis
An imaginary line passing through the center of gravity of an airplane and extending across the airplane from wingtip to wingtip.
Lateral Stability (Rolling)
The stability about the longitudinal axis of an aircraft. Rolling stability or the ability of an airplane to return to level flight due to a disturbance that causes one of the wings to drop.
Latitude
Measurement north or south of the equator in degrees, minutes, and seconds. Lines of latitude are also referred to as parallels.
Leading Edge
The part of an airfoil that meets the airflow first.
Leading Edge Devices
High lift devices which are found on the leading edge of the airfoil. The most common types are fixed slots, movable slats, and leading edge flaps.
Leading Edge Flap
A portion of the leading edge of an airplane wing that folds downward to increase the camber, lift, and drag of the wing. The leading-edge flaps are extended for takeoffs and landings to increase the amount of aerodynamic lift that is produced at any given airspeed.
Licensed Empty Weight
The empty weight that consists of the airframe, engine(s), unusable fuel, and undrainable oil plus standard and optional equipment as specified in the equipment list. Some manufacturers used this term prior to GAMA standardization.
Lift
One of the four main forces acting on an aircraft. On a fixed-wing aircraft, an upward force created by the effect of airflow as it passes over and under the wing.
Limit Load Factor
Amount of stress, or load factor, that an aircraft can withstand before structural damage or failure occurs.
Load Factor
The ratio of the load supported by the airplane’s wings to the actual weight of the aircraft and its contents. Also referred to as G loading.
Longitude
Measurement east or west of the Prime Meridian in degrees, minutes, and seconds. The Prime Meridian is 0° longitude and runs through Greenwich, England. Lines of longitude are also referred to as meridians.
Longitudinal Axis
An imaginary line through an aircraft from nose to tail, passing through its center of gravity. The longitudinal axis is also called the roll axis of the aircraft. Movement of the ailerons rotates an airplane about its longitudinal axis.
Longitudinal Stability (Pitching)
Stability about the lateral axis. A desirable characteristic of an airplane whereby it tends to return to its trimmed angle of attack after displacement.
Loran-C
A radio navigation system that utilizes master and slave stations transmitting timed pulses. The time difference in reception of pulses from several stations establishes a hyperbolic line of position, which can be identified on a LORAN chart. A fix in position is obtained by utilizing signals from two or more stations.
LAADR
Low Altitude Arrival/Departure Routing.
LAHSO
Land and Hold Short Operations. Operations which include simultaneous takeoffs and landings and/or simultaneous landings when a landing aircraft is able and is instructed by the controller to hold short of the intersecting runway/taxiway or designated hold-short point. Pilots are expected to promptly inform the controller if the hold short clearance cannot be accepted.
LO CIGS
Low Ceilings. Low clouds.
LOC
Localizer. The component of an ILS that provides course guidance to the runway.
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