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INTENTIONALLY
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WGS 84
FCTM O.I. (30 JUL 04)
WORLD GEODETIC SURVEY 1984 (WGS 84)
WGS 84 is the standard used for the accurate position reference used by the GPS system. There are some differences between WGS 84 and the more current geodetic survey systems but these differences are less than 2 cm. ICAO recommends that positions of all navigation references are made with respect to WGS 84 and, in most countries around the world, this recommendation has been complied with. There are some states, however, where the conversion to WGS 84 has not been carried out, leading to the possibility of navigation inaccuracies.
Use Of GPS In Non-WGS84 Reference Datum Airspace
In non-WGS 84 airspace, the local datum (position basis) used to survey the navigation data base position information may result in significant position errors from a survey done using the WGS 84 datum. To the pilot, this means that the position of runways, airports, waypoints, or navigation aids, may not be as accurate as depicted on the map display and may not agree with the GPS position. Crews should consult official sources, e.g. Jeppesen, to determine the current status of airspace in which they operate.
A worldwide survey has been conducted which determined that using the FMGS while receiving GPS position updating during enroute navigation, SIDS and STARS achieve the required navigation accuracy, despite operating in non-WGS 84 airspace. However, this navigation position accuracy may not be adequate for approaches. Therefore, the aircraft flight manual requires the crew to inhibit GPS position updating while flying approaches in non-WGS 84 airspace "unless other appropriate procedures are used."
Provided operational approval has been received and measures to ensure their accuracy have been taken, RNAV approaches may be flown with GPS updating enabled. Options available may include surveys of the published approaches to determine if significant differences or position errors exist, developing special RNAV procedures complying with WGS 84 or equivalent, or inhibiting GPS updating.
For approaches based upon ground-based navigation aids such as ILS, VOR, LOC or NDB, the GPS updating need not be inhibited, provided that appropriate raw data is used as the primary navigation reference throughout the approach and missed approach. Aircraft primary lateral and vertical navigation modes may be used. Provided the FMGS is not used as the primary means of navigation for approaches, this method can be used instead of inhibiting GPS updating.
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Honeywell.ID.Conventions
FCTM O.I..(30.JUL.04)
UN-NAMED.OCEANIC.CONTROL.AREA.REPORTING.POINTS
Positions in the Northern Hemisphere use the letters "N" and "E", while positions in the Southern Hemisphere use the letters "S" and "W". Latitude always precedes.longitude.
For.longitude,.only.the.last.two.digits.of.the.three.digit.value.are.used. Placement of the designator in the five character set indicates whether the first longitude digit is 0 or 1. The letter is the last character if the longitude is less than 100. and is the third character if the longitude is 100. or greater. "N" is used for north latitude, west longitude; "E" is used for north latitude, east longitude. "S" is
used for south latitude, east longitude. "W" is used for south latitude, west longitude. Examples: N50. W040. becomes.5040N N75. W170. becomes.75N70 N50. E020. becomes.5020E N06. E110. becomes.06E10 S52. W075. becomes.5275W S07. W120. becomes.07W20 S50. E020. becomes.5020S S06. E110. becomes.06S10
9.70.2
A330/A340 COMMS.&.NAV O.I..(30.JUL.04)
FCTM Honeywell.ID.Conventions
UN-NAMED.TERMINAL.AREA.FIXES DME.ARC.Procedures
Unnamed fixes along a DME arc procedure are identified by a five character
designation.with.the.first.character.being."D". 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：A330/A340 机组训练手册 FCTM Flight Crew Training Manual(94)
