Aeronautical Terms beginning with L
L/MF
Low or Medium Frequency.
L/MF
Low or Medium Frequency.
LAA
Local Airport Advisory
LAADR
Low Altitude Arrival/Departure Routing.
LAAS
Local Area Augmentation System.
LAAS
Local Area Augmentation System
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.
Lag
The delay that occurs before an instrument needle attains a stable indication.
Lag
The delay that occurs before an instrument needle attains a stable indication.
LAHSO
Land and Hold Short Operations
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.
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.
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 possible
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 as soon as practical
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 breeze
A coastal breeze blowing from land to sea, caused by temperature difference when the sea surface is warmer than the adjacent land. Therefore, it usually blows at night and alternates with a sea breeze, which blows in the opposite direction by day.
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.
Land immediately
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.
Land-Based Air Defense Identification Zone
An ADIZ over U.S. metropolitan areas, which is activated and deactivated as needed, with dimensions, activation dates and other relevant information disseminated via NOTAM. Note: ADIZ locations and operating and flight plan requirements for civil aircraft operations are specified in 14 CFR Part 99.
Landing Area
Any locality either on land, water, or structures, including airports/heliports and intermediate landing fields, which is used, or intended to be used, for the landing and takeoff of aircraft whether or not facilities are provided for the shelter, servicing, or for receiving or discharging passengers or cargo.
Landing Direction Indicator
A device which visually indicates the direction in which landings and takeoffs should be made.
Landing Distance Available (LDA)
The runway length declared available and suitable for a landing airplane.
Landing gear extended speed
The maximum speed at which an aircraft can be safely flown with the landing gear extended.
Landing gear operating speed
The maximum speed at which the landing gear can be safely extended or retracted.
Landing Minimums
The minimum visibility prescribed for landing a civil aircraft while using an instrument approach procedure. The minimum applies with other limitations set forth in 14 CFR Part 91 with respect to the Minimum Descent Altitude (MDA) or Decision Height (DH) prescribed in the instrument approach procedures as follows: a. Straight-in landing minimums. A statement of MDA and visibility, or DH and visibility, required for a straight-in landing on a specified runway, or b. Circling minimums. A statement of MDA and visibility required for the circle-to-land maneuver. Note: Descent below the established MDA or DH is not authorized during an approach unless the aircraft is in a position from which a normal approach to the runway of intended landing can be made and adequate visual reference to required visual cues is maintained.
Landing Roll
The distance from the point of touchdown to the point where the aircraft can be brought to a stop or exit the runway.
Landing Sequence
The order in which aircraft are positioned for landing.
Landing Weight
The takeoff weight of an aircraft less the fuel burned and/or dumped en route.
Lapse rate
The rate of decrease of an atmospheric variable with height; commonly refers to decrease of temperature with height.
Large
An Aircraft Class Wake Turbulence Separation Minima. Aircraft of more than 41,000 pounds, maximum certificated takeoff weight, up to but not including 300,000 pounds.
Large Aircraft
An aircraft of more than 12,500 pounds, maximum certificated takeoff weight. As defined in 14 CFR part 1.
Last Assigned Altitude
The last altitude/flight level assigned by ATC and acknowledged by the pilot.
Latent heat
The amount of heat absorbed (converted to kinetic energy) during the processes of change of liquid water to water vapor, ice to water vapor, or ice to liquid water; or the amount released during the reverse processes. Four basic classifications are: latent heat of condensation, latent heat of fusion, latent heat of sublimation, and latent heat of vaporization.
Latent heat of condensation
Heat released during change of water vapor to water.
Latent heat of fusion
Heat released during change of water to ice or the amount absorbed in change of ice to water.
Latent heat of sublimation
Heat released during change of water vapor to ice or the amount absorbed in the change of ice to water vapor.
Latent heat of vaporization
Heat absorbed in the change of water to water vapor; the negative of latent heat of condensation.
Lateral Axis
An imaginary line passing through the center of gravity of an airplane and extending across the airplane from wingtip to wingtip.
Lateral axis
An imaginary line passing through the center of gravity of an airplane and extending across the airplane from wingtip to wingtip.
Lateral Navigation (LNAV)
A function of area navigation (RNAV) equipment which calculates, displays, and provides lateral guidance to a profile or path.
Lateral Navigation (LNAV)
A function of area navigation (RNAV) equipment which calculates, displays, and provides lateral guidance to a profile or path.
Lateral Offset Moment
The moment, in lb-in, of a force that tends to rotate a helicopter about its longitudinal axis. The lateral offset moment is the product of the weight of the object and its distance from butt line zero. Lateral offset moments that tend to rotate the aircraft clockwise are positive, and those that tend to rotate it counterclockwise are negative.
Lateral Separation
The lateral spacing of aircraft at the same altitude by requiring operation on different routes or in different geographical locations.
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.
Layer
In reference to sky cover, clouds or other obscuring phenomena whose bases are approximately at the same level. The layer may be continuous or composed of detached elements. The term “layer” does not imply that a clear space exists between the layers or that the clouds or obscuring phenomena composing them are of the same type.
LDA
Localizer-type Directional Aid.
LDA/PRM
Localizer Type Directional Aid/Precision Runway Monitor
LDIN
Lead-In-Light System. Consists Of One Or More Series Of Flashing Lights Installed At Or Near Ground Level That Provides Positive Visual Guidance Along An Approach Path, Either Curving Or Straight, Where Special Problems Exist With Hazardous Terrain, Obstructions, Or Noise Abatement Procedures
Lead radial
The radial at which the turn from the DME arc to the inbound course is started.
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.
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.
Leading Edge
The part of an airfoil that meets the airflow first.
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.
Lean of Peak
A mixture setting where the mixture was leaned from the full-rich fuel flow position to lean of peak exhaust gas temperature (EGT).
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.
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.
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.
Lee wave
Any stationary wave disturbance caused by a barrier in a fluid flow. In the atmosphere when sufficient moisture is present, this wave will be evidenced by lenticular clouds to the lee of mountain barriers; also called mountain wave or standing wave.
Left Base Area
A type of Terminal Arrival Area. A 30NM arc centered on the right corner IAF (Initial Approach Fix). The area shares a boundary with the straight-in area except that it extends out for 30NM from the IAF and is bounded on the other side by a line extending from the IF through the FAF to the arc.
LEMAC
Leading Edge of the Mean Aerodynamic Chord.
Lenticular cloud (or lenticularis)
A species of cloud whose elements have the form of more or less isolated, generally smooth lenses or almonds. These clouds appear most often in formations of orographic origin, the result of lee waves, in which case they remain nearly stationary with respect to the terrain (standing cloud), but they also occur in regions without marked orography.
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.
Level of free convection (abbreviated LFC)
The level at which a parcel of air lifted dry-adiabatically until saturated and moist-adiabatically thereafter would become warmer than its surroundings in a conditionally unstable atmosphere.
LF
Low Frequency
LFR
Low-Frequency Radio Range.
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.
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
A component of the total aerodynamic force on an airfoil and acts perpendicular to the relative wind.
Lift
A component of the total aerodynamic force on an airfoil and acts perpendicular to the relative wind.
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.
Lifting condensation level (abbreviated LCL)
The level at which a parcel of unsaturated air lifted dry-adiabatically would become saturated. Compare level of free convection and convective condensation level.
Light Gun
A handheld directional light signaling device which emits a brilliant narrow beam of white, green, or red light as selected by the tower controller. The color and type of light transmitted can be used to approve or disapprove anticipated pilot actions where radio communication is not available. The light gun is used for controlling traffic operating in the vicinity of the airport and on the airport movement area.
Light Icing
The rate of accumulation may create a problem if flight is prolonged in this environment (over 1 hour). Occasional use of deicing/anti-icing equipment removes/prevents accumulation. It does not present a problem if the deicing/anti-icing equipment is used.
Light Icing
The rate of ice accumulation may create a problem if flight is prolonged in this environment (over 1 hour). Requires occasional cycling of manual deicing systems1 to minimize ice accretions on the airframe. A representative accretion rate for reference purposes is 1⁄4 inch to 1 inch (0.6 to 2.5 cm) per hour on the outer wing.
Light-sport aircraft
An aircraft, other than a helicopter or powered-lift that, since its original certification, has continued to meet the following:
(1) A maximum takeoff weight of not more than—
(i) 1,320 pounds (600 kilograms) for aircraft not intended for operation on water; or
(ii) 1,430 pounds (650 kilograms) for an aircraft intended for operation on water.
(2) A maximum airspeed in level flight with maximum continuous power (Vh) of not more than 120 knots CAS under standard atmospheric conditions at sea level.
(3) A maximum never-exceed speed (Vne) of not more than 120 knots CAS for a glider.
(4) A maximum stalling speed or minimum steady flight speed without the use of lift-enhancing devices (Vs1) of not more than 45 knots CAS at the aircraft’s maximum certificated takeoff weight and most critical center of gravity.
(5) A maximum seating capacity of no more than two persons, including the pilot.
(6) A single, reciprocating engine, if powered.
(7) A fixed or ground-adjustable propeller if a powered aircraft other than a powered glider.
(8) A fixed or feathering propeller system if a powered glider.
(9) A fixed-pitch, semi-rigid, teetering, two-blade rotor system, if a gyroplane.
(10) A non-pressurized cabin, if equipped with a cabin.
(11) Fixed landing gear, except for an aircraft intended for operation on water or a glider.
(12) Fixed or retractable landing gear, or a hull, for an aircraft intended for operation on water.
(13) Fixed or retractable landing gear for a glider.
Lighted Airport
An airport where runway and obstruction lighting is available.
Lighter-than-air aircraft
Aircraft that can rise and remain suspended by using contained gas weighing less than the air that is displaced by the gas.
Lightning
Generally, any and all forms of visible electrical discharge produced by a thunderstorm.
Limit Load Factor
Amount of stress, or load factor, that an aircraft can withstand before structural damage or failure occurs.
Line Up And Wait (LUAW)
Used by ATC to inform a pilot to taxi onto the departure runway to line up and wait. It is not authorization for takeoff. It is used when takeoff clearance cannot immediately be issued because of traffic or other reasons.
Lines of flux
Invisible lines of magnetic force passing between the poles of a magnet.
Lines of flux
Invisible lines of magnetic force passing between the poles of a magnet.
Liquid Water Content (LWC)
The total mass of water in all the liquid cloud drops within a unit volume of cloud. LWC is usually discussed in terms of grams of water per cubic meter of air (g/m3).
LIRL
Low Intensity Runway Lights
Lithometeor
The general term for dry particles suspended in the atmosphere such as dust, haze, smoke, and sand.
LLWAS
Low Level Wind Shear Alert System
LMM
Locator Middle Marker.
LNAV
Lateral Navigation
LO CIGS
Low Ceilings. Low clouds.
LOA
Letter Of Agreement/Letter Of Authorization
Load Cell
A component in an electronic weighing system that is placed between the jack and the jack pad on the aircraft. The load cell contains strain gauges whose resistance changes with the weight on the cell.
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.
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.
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.
Loading Graph
A graph of load weight and load moment indexes. Diagonal lines for each item relate the weight to the moment index without having to use mathematics.
Loading Schedule
A method for calculating and documenting aircraft weight and balance prior to taxiing, to ensure the aircraft will remain within all required weight and balance limitations throughout the flight.
Loadmeter
A type of ammeter installed between the generator output and the main bus in an aircraft electrical system.
Loadmeter
A type of ammeter installed between the generator output and the main bus in an aircraft electrical system.
LOC
Localizer.
LOC
Localizer. The component of an ILS that provides course guidance to the runway.
Local Traffic
Aircraft operating in the traffic pattern or within sight of the tower, or aircraft known to be departing or arriving from flight in local practice areas, or aircraft executing practice instrument approaches at the airport.
Localizer (LOC)
The portion of an ILS that gives left/right guidance information down the centerline of the instrument runway for final approach.
Localizer (LOC)
The portion of an ILS that gives left/right guidance information down the centerline of the instrument runway for final approach.
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 1/2 SM 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.
Localizer Usable Distance
The maximum distance from the localizer transmitter at a specified altitude, as verified by flight inspection, at which reliable course information is continuously received.
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
Locator Outer Marker.
Long Range Navigation
LORAN. [Decommissioned in 2010]
Long range navigation (LORAN)
[Decommissioned in 2010] 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.
Long-range communication system (LRCS)
A system that uses satellite relay, data link, high frequency, or another approved communication system which extends beyond line of sight.
Long-range navigation system (LRNS)
An electronic navigation unit that is approved for use under instrument flight rules as a primary means of navigation, and has at least one source of navigational input, such as inertial navigation system, global positioning system, Omega/very low frequency, or Loran C.
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.
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 Axis
An imaginary line through an aircraft from nose to tail, passing through its center of gravity.
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 Balance
Balance around the pitch, or lateral, axis.
Longitudinal Separation
The longitudinal spacing of aircraft at the same altitude by a minimum distance expressed in units of time or miles.
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.
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.
LOP
Line-of-position
LOP
Lean of Peak
LORAN
Long Range Navigation. [Decommissioned in 2010]
LORAN-C
[Decommissioned in 2010] 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.
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.
Lost Communications
Loss of the ability to communicate by radio. Aircraft are sometimes referred to as NORDO (No Radio). Standard pilot procedures are specified in 14 CFR Part 91. Radar controllers issue procedures for pilots to follow in the event of lost communications during a radar approach when weather reports indicate that an aircraft will likely encounter IFR weather conditions during the approach.
Low
An area of low barometric pressure, with its attendant system of winds. Also called a barometric depression or cyclone.
Low Altitude Airway Structure
The network of airways serving aircraft operations up to but not including 18,000 feet MSL.
Low Altitude Alert System
An automated function of the TPX-42 that alerts the controller when a Mode C transponder equipped aircraft on an IFR flight plan is below a predetermined minimum safe altitude. If requested by the pilot, Low Altitude Alert System monitoring is also available to VFR Mode C transponder equipped aircraft.
Low Altitude Alert, Check Your Altitude Immediately
Safety Alert.
Low Approach
An approach over an airport or runway following an instrument approach or a VFR approach including the go-around maneuver where the pilot intentionally does not make contact with the runway.
Low Frequency
The frequency band between 30 and 300 kHz.
Low Level Autorotation
Commences at an altitude well below the traffic pattern, usually below 100 feet AGL and is used primarily for tactical military training.
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.
Low or medium frequency
A frequency range between 190 and 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.
LP
Localizer Performance
LPV
A Type Of Approach With Vertical Guidance (APV) Based On Waas, Published On RNAV (GPS) Approach Charts. This Procedure Takes Advantage Of The Precise Lateral Guidance Available From Waas. The Minima Is Published As A Decision Altitude (DA)
LTP
Landing Threshold Point
LUAW
Line Up and Wait
LUAW
Line Up And Wait
Lubber line
The reference line used in a magnetic compass or heading indicator.
Lubberline
The reference line used in a magnetic compass or heading indicator.
LZ
Landing Zone
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