Devenition And Abreviation Aeronautical Telecommunication (Alphabet L, M, N)

Landing area. That part of a movement area intended for the landing or take-off of aircraft. 

Landing decision point (LDP). The point used in determining landing performance from which, a power-unit failure occurring at this point, the landing may be safely continued or a balked landing initiated. 

Landing gear extended speed means the maximum speed at which an aircraft can be safely flown with the landing gear extended. 

Landing surface. That part of the surface of an aerodrome which the aerodrome authority has declared available for the normal ground or water run of aircraft landing in a particular direction. 

Landing direction indicator. A device to indicate visually the direction currently designated for landing and for take-off. 

Laser-beam critical flight zone (LCFZ). Airspace in the proximity of an aerodrome but beyond the LFFZ where the irradiance is restricted to a level unlikely to cause glare effects. 

Laser-beam free flight zone (LFFZ). Airspace in the immediate proximity to the aerodrome where the irradiance is restricted to a level unlikely to cause any visual disruption. 

Laser-beam sensitive flight zone (LSFZ). Airspace outside, and not necessarily contiguous with, the LFFZ and LCFZ where the irradiance is restricted to a level unlikely to cause flash-blindness or after-image effects. 

Large aircraft means any aircraft having a maximum certified take-off weight (MTOW) of greater than 5700 kg (12500 pounds). 

Level. A generic term relating to the vertical position of an aircraft in flight and meaning variously, height, altitude or flight level. 

Lighting system reliability. The probability that the complete installation operates within the specified tolerances and that the system is operationally usable. 

Limit loads. The maximum loads assumed to occur in the anticipated operating conditions. 

Licence. A document issued by, or under a delegation of authority from the Director, which authorizes the holder to exercise certain privileges as specified in that license, subject to the conditions and limitations contained therein. A basic certificate is equivalent to a licence without ratings and is issued by the DGCA to persons who meet the age, knowledge, skill and experience requirements of CASR Part 65. A certificate of maintenance approval is equivalent to a licence, but the group or type ratings may be limited in respect of validity and scope. A licence is the document described in Annex 1, Chapter 4, paragraph 4.2.
A group rating is a rating covering a group of aircraft or components. Groups of aircraft or components shall be as determined by the DGCA. A type rating is a rating for a specified individual aircraft or component. A group or type rating, when added to a basic certificate, is a licence. The scope of a group or type rating defines the range of aircraft or components for which the rating is valid. The scope of a licence rating is fixed. The scope of a rating on a certificate of maintenance approval may be limited as the DGCA decides. A workshop engineer, is a person who holds a licence rating or a certificate of maintenance approval granting privileges for the certification of specified aircraft or components after overhaul or repair. 

Licensing Authority. The Authority designated by a Contracting State as responsible for the licensing of personnel. 

Lighter-than-air aircraft means aircraft that can rise and remain suspended by using contained gas weighing less than the air that is displaced by the gas. 

Litre (L). A unit of volume restricted to the measurement of liquids and gases which is equal to 1 cubic decimetre. 

Load factor means 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, inertia forces, or ground or water reactions. 

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. 

Lumen (lm). The luminous flux emitted in a solid angle of 1 steradian by a point source having a uniform intensity of 1 candela. 

Lux (lx). The illuminance produced by a luminous flux of 1 lumen uniformly distributed over a surface of 1 square metre.
 

Mach number means the ratio of true airspeed to the speed of sound. 

Magnetic variation. The angular difference between True North and Magnetic North. 

Main rotor means the rotor that supplies the principal lift to a rotorcraft.

Maintenance. The performance of tasks required to ensure the continuing airworthiness of an aircraft, including any one or combination of overhaul, inspection, replacement, defect rectification, and the embodiment of a modification or repair. 

Maintenance organization’s procedures manual. A document endorsed by the head of the maintenance organization which details the maintenance organization’s structure and management responsibilities, scope of work, description of facilities, maintenance procedures and quality assurance or inspection systems. 

Maintenance program mean a document which describes the specific scheduled maintenance tasks and their frequency of completion and related procedures, such as a reliability program, necessary for the safe operation of those aircraft to which it applies. 

Maintenance release mean a document which contains a certification conforming that the maintenance work to which it relates has been completed in a satisfactory manner, either in accordance with the approved data and the procedure described in maintenance organizations procedures manual or under an equivalent system. 

Major alteration means an alteration not listed in the aircraft, aircraft engine, or propeller specifications - 

(1) That might appreciably affect weight, balance, structural strength, performance, 

      powerplant operation, flight characteristics, or other qualities affecting airworthiness; or 

(2) That is not done according to accepted practices or cannot be done by elementary operations.
 

Major repair means a repair: 

(1) That, if improperly done, might appreciably affect weight, balance, structural 

     strength, performance, powerplant operation, flight characteristics, or other 

     qualities affecting airworthiness; or 

(2) That is not done according to accepted practices or cannot be done by elementary operations. 

Manifold pressure means absolute pressure as measured at the appropriate point in the induction system and usually expressed in inches of mercury. 

Manoeuvring area. That part of an aerodrome to be used for the take-off, landing and taxiing of aircraft, excluding aprons. 

Marking. A symbol or group of symbols displayed on the surface of the movement area in order to convey aeronautical information. 

Marker. An object displayed above ground level in order to indicate an obstacle or delineate a boundary. 

Master minimum equipment list (MMEL) means a list established for a particular aircraft type by the organization responsible for the type design with the approval of the state of Design containing items, one or more of which is permitted to be unserviceable at the commencement of flight. The MMEL may be associated with special operating condition, limitations or procedures. 

Maximum mass. Maximum certificated take-off mass.
 

Maximum speed for stability characteristics, VFC/MFC means a speed that may not be less than a speed midway between maximum operating limit speed (VMO/MMO) and demonstrated flight diving speed (VDF/MDF), except that, for altitudes where the Mach number is the limiting factor, MFC need not exceed the Mach number at which effective speed warning occurs. 

Mean power (of a radio transmitter). The average power supplied to the antenna transmission line by a transmitter during an interval of time sufficiently long compared with the lowest frequency encountered in the modulation taken under normal operating conditions. 

Medical Assessment. The evidence issued by a Contracting State that the licence holder meets specific requirements of medical fitness. It is issued following an evaluation by the Licensing Authority of the report submitted by the designated medical examiner who conducted the examination of the applicant for the licence. 

Medical certificate means acceptable evidence of physical fitness on a form prescribed by the DGCA.. 

Metadata. Data about data (ISO 19115). 

METAR application. A FIS application that supports the D-METAR. 

Meteorological authority. The authority providing or arranging for the provision of meteorological service for international air navigation on behalf of a Contracting State. 

Meteorological bulletin. A text comprising meteorological information preceded by an appropriate heading. 

Meteorological information. Meteorological report, analysis, forecast, and any other statement relating to existing or expected meteorological conditions. 

Meteorological office. An office designated to provide meteorological service for international air navigation. 

Meteorological operational channel. A channel of the aeronautical fixed service (AFS), for the exchange of aeronautical meteorological information. 

Meteorological operational telecommunication network. An integrated system of meteorological operational channels, as part of the aeronautical fixed service (AFS), for the exchange of aeronautical meteorological information between the aeronautical fixed stations within the network. 

Meteorological report. A statement of observed meteorological conditions related to a specified time and location. 

Meteorological satellite. An artificial Earth satellite making meteorological observations and transmitting these observations to Earth. 

Metre (m). The distance travelled by light in a vacuum during 1/299 792 458 of a second. 

Military operations area. A military operations area (MOA) is airspace established outside Class A airspace to separate or segregate certain nonhazardous military activities from IFR Traffic and to identify for VFR traffic where these activities are conducted.
 

Minimum descent altitude (MDA) or minimum descent height (MDH) means the lowest altitude, expressed in feet above mean sea level, to which descent is authorized on final approach or during circle to land maneuvering in execution of a standard instrument approach procedure, where no electronic glide slope is provided. 

Minimum equipment list (MEL). A list which provides for the operation of aircraft, subject to specified conditions, with particular equipment inoperative, prepared by an operator in conformity with, or more restrictive than, the MMEL established for the aircraft type. 

Minimum sector altitude. The lowest altitude which may be used which will provide a minimum clearance of 300 m (1 000 ft) above all objects located in the area contained within a sector of a circle of 46 km (25 NM) radius centred on a radio aid to navigation. 

Minor alteration means an alteration other than a major alteration. 

Minor repair means a repair other than a major repair. 

Missed approach point (MAPt). That point in an instrument approach procedure at or before which the prescribed missed approach procedure must be initiated in order to ensure that the minimum obstacle clearance is not infringed. 

Missed approach procedure. The procedure to be followed if the approach cannot be continued. 

Mobile surface station. A station in the aeronautical telecommunication service, other than an aircraft station, intended to be used while in motion or during halts at unspecified points. 

Mode S subnetwork. A means of performing an interchange of digital data through the use of secondary surveillance radar (SSR) Mode S interrogators and transponders in accordance with defined protocols. 

Mole (mol). The amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon-12. 

Movement area. That part of an aerodrome to be used for the take-off, landing and taxiing of aircraft, consisting of the manoeuvring area and the apron(s). 

Multi-Landing Operation – Any helicopter operation where a pilot performs 30 take-off and landings within a 24 hour period.
 

Nautical mile (NM). The length equal to 1 852 metres exactly. Navigable airspace means airspace at and above the minimum flight altitudes prescribed by or under this chapter, including airspace needed for safe takeoff and landing. 

Near-parallel runways. Non-intersecting runways whose extended centre lines have an angle of convergence/divergence of 15 degrees or less. 

Net Take-off Path. Means the one-engine-inoperative flight path that starts at a height of 35 feet at the end of the take-off distance required and extends to a height of at least 1500 feet AGL, reduced at each point by a gradient of climb equal to 0.8 per cent for two-engine aeroplanes, 0.9 per cent for three-engine aeroplanes and 1.0 percent for four-engine aeroplanes. 

Network station. An aeronautical station forming part of a radiotelephony network. 

Newton (N). The force which when applied to a body having a mass of 1 kilogram gives it an acceleration of 1 metre per second squared. 

Next data authority. The ground system so designated by the current data authority through which an onward transfer of communications and control can take place. 

Night. The hours between the end of evening civil twilight and the beginning of morning civil twilight or such other period between sunset and sunrise, as may be prescribed by the appropriate authority. 

Non-instrument runway. A runway intended for the operation of aircraft using visual approach procedures. 

Non precision approach procedure means a standard instrument approach procedure in which no electronic glide slope is provided. 

Non-network communications. Radiotelephony communications conducted by a station of the aeronautical mobile service, other than those conducted as part of a radiotelephony network. 

Normal flight zone (NFZ). Airspace not defined as LFFZ, LCFZ or LSFZ but which must be protected from laser radiation capable of causing biological damage to the eye. 

NOTAM. A notice distributed by means of telecommunication containing information concerning the establishment, condition or change in any aeronautical facility, service, procedure or hazard, the timely knowledge of which is essential to personnel concerned with flight operations.