IFR Equipment & Requirements
ATC Procedures & Communications
Airspace & Altitudes
Navigation & Approach Procedures
Instrument Procedures & Techniques
Lost Communications & Emergency Procedures
Weather Theory & Hazards
Icing & Cold Weather Operations
Human Factors & Illusions
Miscellaneous Regulations & Information
An Area Forecast (FA) is a forecast in an abbreviated plain language of speci ed weather phenomena covering a ight information region (FIR)
or other area designated by the meteorological authority. The Area Forecast (in conjunction with AIRMETs, SIGMETs, Convective SIGMETs,
CWAs, etc.), is used to determine forecast en route weather and to interpolate conditions at airports which do not have a Terminal
Aerodrome Forecast (TAF). As such, it serves as a ight planning and pilot weather brie ng aid for use by general aviation pilots, civil and
military aviation operations and Federal Aviation Administration (FAA) weather briefers.
Note...Hazardous weather (e.g., IFR, icing, turbulence, etc.) meeting AIRMET or SIGMET criteria are not forecast in the CONUS or Hawaii
FAs.Valid AIRMETs and SIGMETs must be used in conjunction with the FA to determine hazardous weather information for the ight.
LNAV+V is advisory only – It provides a glidepath for situational awareness, but it is not an authorized glidepath for vertical navigation under
WAAS minimums.You must use LNAV minimums – Since LNAV+V is only an aid, you are still ying an LNAV (lateral navigation) approach,
which means you must adhere to step-down altitudes and use the barometric altimeter as your primary altitude reference. Do not descend
below the LNAV MDA early – Unlike an LPV approach, which allows descent to a decision altitude (DA), an LNAV approach has a Minimum
Descent Altitude (MDA), requiring you to remain at or above it until you establish the required visibility to land.
DME measures the straight-line distance (or slant range) between the aircraft and the DME ground station, rather than horizontal ground
distance. This means that when an aircraft is close to the DME station but at a high altitude, the reading is slightly exaggerated because it
includes both the horizontal and vertical components of distance. The guideline states that DME is considered accurate if the aircraft is at a
horizontal distance at least equal to its altitude in thousands of feet:
Example 1: If an aircraft is ying at 5,000 feet (5,000 ft = 5 NM) above the DME facility, the DME reading is considered reliable if the aircraft is
at least 5 NM away.
Example 2: At 10,000 feet (10 NM), the DME reading is usable when the aircraft is at least 10 NM from the station.
An operational service volume has been established for each class in which adequate signal coverage and frequency protection can be assured.
To facilitate use of VOR,VORTAC, or TACAN aids, consistent with their operational service volume limits, pilot use of such aids for de ning a
direct route of ight in controlled airspace should not exceed the following: Operations above FL 450 - Use aids not more than 200 NM
apart. These aids are depicted on enroute high altitude charts. Operation off established routes from 18,000 feet MSL to FL 450 - Use aids not
more than 260 NM apart. These aids are depicted on enroute high altitude charts. Operation off established airways below 18,000 feet MSL -
Use aids not more than 80 NM apart. These aids are depicted on enroute low altitude charts. Operation off established airways between
14,500 feet MSL and 17,999 feet MSL in the conterminous U.S. - facilities not more than 200 NM apart may be used.
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