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 ⁄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.  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 Guidance.  Magnetic Variation. The difference in degrees between  the measured values of true north and magnetic north at  that location.  Maximum Authorized Altitude (MAA). An MAA is a  published altitude representing the maximum usable  altitude or flight level for an airspace structure or route  segment. It is the highest altitude on a Federal airway, jet  route, RNAV low or high route, or other direct route for  which an MEA is designated at which adequate reception  of navigation signals is assured.  Metering Fix. A fix along an established route over which  aircraft are metered prior to entering terminal airspace.  Normally, this fix should be established at a distance from  the airport which facilitates a profile descent 10,000 feet  above airport elevation (AAE) or above.  Mid-RVR. The RVR readout values obtained from sensors  located midfield of the runway.  Mileage Break. A point on a route where the leg segment  mileage ends, and a new leg segment mileage begins, often  at a route turning point.  Military Airspace Management System (MAMS). A  Department of Defense system to collect and disseminate  information on the current status of special use airspace.  This information is provided to the Special Use Airspace  Management System (SAMS). The electronic interface  also provides SUA schedules and historical activation and  utilization data.  Minimum Crossing Altitude (MCA). An MCA is the lowest  altitude at certain fixes at which the aircraft must cross  when proceeding in the direction of a higher minimum en  route IFR altitude. MCAs are established in all cases where  obstacles intervene to prevent pilots from maintaining  obstacle clearance during a normal climb to a higher MEA  after passing a point beyond which the higher MEA applies.  Minimum Descent Altitude (MDA). 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 En Route Altitude (MEA). The MEA is the lowest  published altitude between radio fixes that assures  acceptable navigational signal coverage and meets  obstacle clearance requirements between those fixes. The  MEA prescribed for a Federal Airway or segment, RNAV low  or high route, or other direct route applies to the entire  width of the airway, segment, or route between the radio  fixes defining the airway, segment, or route.  Minimum IFR Altitude (MIA). Minimum altitudes for IFR  operations are prescribed in 14 CFR Part 91. These MIAs are  published on IFR charts and prescribed in 14 CFR Part 95  for airways and routes, and in 14 CFR Part 97 for standard  instrument approach procedures.  Minimum Navigation Performance Specifications (MNPS).  A set of standards that require aircraft to have a minimum  navigation performance capability in order to operate in  MNPS designated airspace. In addition, aircraft must be  certified by their State of Registry for MNPS operation.  Under certain conditions, non-MNPS aircraft can operate  in MNPS airspace, however, standard oceanic separation  minima is provided between the non-MNPS aircraft and  other traffic.  Minimum Obstruction Clearance Altitude (MOCA). The  MOCA is the lowest published altitude in effect between  radio fixes on VOR airways, off-airway routes, or route  segments that meets obstacle clearance requirements  for the entire route segment. This altitude also assures  acceptable navigational signal coverage only within 22  NM of a VOR.  G-6 