Adrian Lewer Posted December 30, 2008 Posted December 30, 2008 Hi all AreaFor is done in True format but what are Metar's and Taf's done in ? Both true as well, as far as i am aware (and what the BAK says) yes they are? but would like to double check...
motzartmerv Posted December 30, 2008 Posted December 30, 2008 No, i think taf's are magnetic... so runway hd's and winds are both magnetic.. It makes sence because the arfor covers large areas that may have 2 isagonals running through them...perhaps...??
ossie Posted December 30, 2008 Posted December 30, 2008 Yes Adrian you are correct TAF's, METAR's and SPECI's are in True. The BOM Aeronautical Services Handbook has all the info - http://www.bom.gov.au/general/reg/ash/ASH.pdf Cheers Os
Adrian Lewer Posted December 30, 2008 Author Posted December 30, 2008 yes this is what i was taught but my day vfr study guide says all 3 in true i am so confused on this situation at the moment
lazerin Posted December 30, 2008 Posted December 30, 2008 My instructor taught me an easy rule: If it's written, it's true. If it's spoken, it's magnetic. Thus, all TAF, ARFOR, METAR, SPECI etc are in true. ATIS will be magnetic.
Adrian Lewer Posted December 30, 2008 Author Posted December 30, 2008 i will check out the page when i get home in the morning. so if they are true we must add or subtract our magnetic variation which in our case is subtract then apply our wind
motzartmerv Posted December 30, 2008 Posted December 30, 2008 Ahh, thats a good one lazerin.. thats why i was confused, the atis is what we use most of the time at cn... sorry:loopy:
Guest 3rd dimension Posted March 7, 2009 Posted March 7, 2009 Here is a basic rule I was taught by a very high hour pilot. If it is spoken eg awis, atis or by radio it is magnetic. If it is written it is true eg taf, area eg. Hope it helps.
Guest 3rd dimension Posted March 7, 2009 Posted March 7, 2009 Sorry Lazerin - I over looked you comment. Anyway good to see we agree.
Guest rajagiri Posted June 4, 2009 Posted June 4, 2009 hi If it's written, it's true. If it's spoken, it's magnetic.:pig:
GraemeK Posted June 4, 2009 Posted June 4, 2009 If it's written, it's true. If it's spoken, it's magnetic. Thus, all TAF, ARFOR, METAR, SPECI etc are in true. ATIS will be magnetic. Correct - that's how I remember which is which (need all the help I can get to remember things these days!!) ....
Ultralights Posted June 4, 2009 Posted June 4, 2009 i have a similar shorter one, if its on paper, it true.
Guest Ken deVos Posted June 4, 2009 Posted June 4, 2009 i have a similar shorter one, if its on paper, it true. I like your method Ultralights, that stops any confusion with written runway headings which are magnetic A little off subject, but is there an easy way to distinguish cloud heights (AMSL or AGL) in the various forecasts :confused:
Guest Ken deVos Posted June 5, 2009 Posted June 5, 2009 [snip] I thought all were given as AMSL unless stated otherwise.......... Right or Wrong?Cheers Dexter My understanding is that TAFs are AGL as described here: Decoding a TAF "SCT040 BKN100 are the cloud amounts and heights above the aerodrome (in 100's of feet) Cloud amount is expressed as SKC, FEW, SCT, BKN or OVC"
Mazda Posted June 10, 2009 Posted June 10, 2009 Yep! Spoken is magnetic, written is true, area forecasts AMSL, anything aerodrome related like TAFs are AGL. Clear as mud!!! :thumb_up:
Guest Mad Dave Posted June 10, 2009 Posted June 10, 2009 It kind of makes sense if you think about it as well, because how could an area forecast be AGL? Whereas a TAF really has to be (in relation to overflying, circuits etc.)
Ross Posted June 11, 2009 Posted June 11, 2009 Magnetic variation changes as you fly North or South or East or West so your magnetic compass heading theoretically needs to gradually change if you flew a long enough track to cross a few compass variation lines-ignoring great circle tracking for our type of flying. If you go flying near Iron Ore deposits you might have to ignore your compass completely. Lang Hancock is supposed to have found his Iron ore deposits due to aircraft compass anomalies when flying in a light plane over the area. It is normal or close enough usually to take an average deviation into account from the start to the end of each straight line portion of the track on the map especially as we are all flying VFR in RAA aircraft so far. Another factor is that the compass variation at a particular location changes over time. New issued WAC charts take this into account but my new current Canberra WAC chart is possibly at least four years out of date. I have two Canberra WAC charts for Canberra. Eighth edition dated 1981 . This one says isogonic information based on 1980 info (lines of equal magnetic declination). Sixteenth edition dated Jan 2008. This one says the Magnetic variation info is 2005 info. They respectively show magnetic variations for Griffith NSW of about 10.4 degrees East and 10.9 degrees East for 2005. Eventually the Magnetic North and South poles will flip (swap over). I don't want to be still flying when that happens. From what I remember flying from Griffith to Ballarat results in flying down a track with almost the same magnetic variation from start to finish. My ERSA lists the deviations in whole degrees with both as 11 degrees East.
Guest pelorus32 Posted June 12, 2009 Posted June 12, 2009 Magnetic variation changes as you fly North or South or East or West so your magnetic compass heading theoretically needs to gradually change if you flew a long enough track to cross a few compass variation lines-ignoring great circle tracking for our type of flying. If you go flying near Iron Ore deposits you might have to ignore your compass completely. Lang Hancock is supposed to have found his Iron ore deposits due to aircraft compass anomalies when flying in a light plane over the area. It is normal or close enough usually to take an average deviation into account from the start to the end of each straight line portion of the track on the map especially as we are all flying VFR in RAA aircraft so far. Another factor is that the compass variation at a particular location changes over time. New issued WAC charts take this into account but my new current Canberra WAC chart is possibly at least four years out of date. I have two Canberra WAC charts for Canberra. Eighth edition dated 1981 . This one says isogonic information based on 1980 info (lines of equal magnetic declination). Sixteenth edition dated Jan 2008. This one says the Magnetic variation info is 2005 info. They respectively show magnetic variations for Griffith NSW of about 10.4 degrees East and 10.9 degrees East for 2005. Eventually the Magnetic North and South poles will flip (swap over). I don't want to be still flying when that happens. From what I remember flying from Griffith to Ballarat results in flying down a track with almost the same magnetic variation from start to finish. My ERSA lists the deviations in whole degrees with both as 11 degrees East. This is a very well known process. Marine charts don't have isogonals in the way WACs do. However they have compass roses that show the variation and tell you how much the variation changes each year and in which direction. Regards Mike
GraemeK Posted June 12, 2009 Posted June 12, 2009 They respectively show magnetic variations for Griffith NSW of about 10.4 degrees East and 10.9 degrees East for 2005. ..... My ERSA lists the deviations in whole degrees with both as 11 degrees East. To be honest - in the Jab I'm stuffed if I can pick up something like a coupla degrees either way when I'm in the air, especially if there's a bit of turbulence .... So it's a bit academic really !!
ossie Posted June 12, 2009 Posted June 12, 2009 The World Magnetic Model is updated at 5 yearly intervals, and MagVar for aeronautical charts and flight planning systems are updated at each release. The next model is due for release in Dec this year. Here's a link to the website for those interested :- World Magnetic Model - Fortran Download
flying dog Posted June 24, 2009 Posted June 24, 2009 My instructor taught me an easy rule:If it's written, it's true. If it's spoken, it's magnetic. Thus, all TAF, ARFOR, METAR, SPECI etc are in true. ATIS will be magnetic. Hey, that's a good one/way to remember it.
Guest Kevin the Penniless Posted November 8, 2009 Posted November 8, 2009 That BOM site requires a password. Can you make the pdf available to us lowly plebs that do not have passwords?
Guest magcheck Posted November 8, 2009 Posted November 8, 2009 That BOM site requires a password. Can you make the pdf available to us lowly plebs that do not have passwords? You can get the password and Username on the login pagae l Aviation Products are accessed via username:bomw0007 and password:aviation. By entering this username and password you are acknowledging that all Aviation products produced by the Bureau of Meteorology are for aviation users only. Aviation Weather Services
GraemeK Posted November 8, 2009 Posted November 8, 2009 All BOM aviation services require a user name and password - these are both freely available on the BOM website. The user name is bomw0007 and the password is aviation! EDIT: beaten by a minute!!
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