400 FEET
400 FEET
VRNP VALUE FOR OCEANIC, EN ROUTE, AND TERMINAL PHASES OF FLIGHT
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11.31.10 June 1, 2005
Flight Management, Navigation -Flight Management System Operation
737 Flight Crew Operations Manual
When required, VRNP values may be manually entered or displayed on RNP PROGRESS page 4/4. The FMC will accept manual entry of a VRNP value greater than the default value, but the VERIFY VERT RNP VALUE advisory message will be displayed in the scratchpad. Manual entries are cleared at flight completion.
Lateral Navigation (LNAV)
LNAV provides steering commands to the next waypoint. If selected, LNAV engages when laterally within 3 nautical miles of the active route leg. If outside of 3 nautical miles of the active route leg, LNAV engages if on an intercept heading of 90 degrees or less and the intercept will occur before the active waypoint. FMC LNAV guidance normally provides great circle courses between waypoints. However, when an arrival or approach from the FMC database is entered into the active route, the FMC can supply commands to fly a constant heading, track, or follow an arc, as required by the procedure.
Waypoints
Waypoint (navigation fix) identifiers are displayed on the CDU and navigation display.
The CDU message NOT IN DATA BASE is displayed if a manually entered waypoint identifier is not stored in the database. The waypoint can still be entered as a latitude/longitude, place–bearing/distance or place–bearing/place–bearing waypoint.
FMC–generated waypoints contain a maximum of five characters assigned according to the following rules.
Navaid Waypoint Names
VHF – waypoints located at VHF navaids (VOR/DME/LOC) are identified by the official one, two, three or four character facility identifier. Examples:
.
Los Angeles VORTAC – LAX
.
Tyndall TACAN – PAM
.
Riga, Latvia – RIX.
NDB – waypoints located at NDBs are identified by use of the station identifier. Example:
. Fort Nelson, CAN – YE.
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Flight Management, Navigation -Flight Management System Operation 737 Flight Crew Operations Manual
Fix Waypoint Names
Fixes with one–word names – waypoints located at fixes with names containing five or fewer characters are identified by the name. Examples:
.
DOT
.
ACRA
.
ALPHA.
Long Waypoint Names
Names with more than five characters are abbreviated using the following rules sequentially until five characters remain. Double letters are deleted. Examples:
.
KIMMEL becomes KIMEL
.
COTTON becomes COTON
.
RABBITT becomes RABIT.
Keep the first letter, first vowel and last letter. Delete other vowels starting from right to left. Examples:
.
ADOLPH becomes ADLPH
.
BAILEY becomes BAILY
.
BURWELL becomes BURWL. Keep the last letter, then delete consonants from right to left. Examples:
.
ANDREWS becomes ANDRS
.
BRIDGEPORT becomes BRIDT
.
HORSBA becomes HORSA.
Fixes with multiword names use the first letter of the first word and abbreviate the last word, using the above rules sequentially until a total of five characters remain. Examples:
.
CLEAR LAKE becomes CLAKE
.
ROUGH ROAD becomes RROAD.
Unnamed Point Waypoint Names
Unnamed turn points, intersections and DME fixes – if an unnamed turn point, intersection or fix is collocated with a named waypoint or navaid on a different route structure (such as low altitude routes or an approach), the name or identifier of the collocated waypoint is used. Example:
. Unnamed turn point on J2 between the Lake Charles (LCH) and New
Orleans (MSY) VORTACs is coincidental with the Lafayette (LFT) low
altitude VORTAC. LFT is used as the identifier for the turn point.
Copyright . The Boeing Company. See title page for details.
11.31.12 September 27, 2004
Flight Management, Navigation -Flight Management System
Operation
737 Flight Crew Operations Manual
Identifier codes for unnamed turn points not coincidental with named waypoints are constructed from the identifier of a navaid serving the point and the distance from the navaid to the point. If the distance is 99 nautical miles or less, the navaid identifier is placed first, followed by the distance. If the distance is 100 nautical miles or more, the last two digits are used and placed ahead of the navaid identifier. Examples (NAVAID – DISTANCE – IDENT):
.
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