Aeronautical Terms beginning with L
L/MF
Low or Medium Frequency.
LAADR
Low Altitude Arrival/Departure Routing.
LAAS
Local Area Augmentation System.
Lag
The delay that occurs before an instrument needle attains a stable indication.
LAHSO
Land and Hold Short Operations
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.
Last Assigned Altitude
The last altitude/flight level assigned by ATC and acknowledged by the pilot.
Lateral Navigation (LNAV)
A function of area navigation (RNAV) equipment which calculates, displays, and provides lateral guidance to a profile or path.
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.
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.
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.
LF
Low Frequency
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.
LMM
Locator Middle Marker.
LNAV
Lateral Navigation
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
Localizer.
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-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] 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.
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 Separation
The longitudinal spacing of aircraft at the same altitude by a minimum distance expressed in units of time or miles.
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.
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 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.
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
Lubber line
The reference line used in a magnetic compass or heading indicator.
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