ZU-DVE (and ZS-WUO) (and ZEE) Flight Log
- Junkie
- The sky is all mine
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- Joined: Tue May 24, 2005 9:01 am
- Location: Killed in microlight accident 23rd December 2006
... You may have to rely on your map and compass, any time the gizmos decide to go south on you.
How often do you practice planning & plotting your route, wind, distance, etc (Triangle of velocities) beforehand and then try to flying the route on compass only along with applying any of the techniques to maintain your track that you(should have) learned at flight school.
Not easym but can also be quite reqrding when you start to get the hang of it - you might need for real one day.
How often do you practice planning & plotting your route, wind, distance, etc (Triangle of velocities) beforehand and then try to flying the route on compass only along with applying any of the techniques to maintain your track that you(should have) learned at flight school.
Not easym but can also be quite reqrding when you start to get the hang of it - you might need for real one day.
J.U.N.K.I.E 's
Finest used aviation parts in all the Universe
No credit / No returns
Finest used aviation parts in all the Universe
No credit / No returns
I prefer to use magnetic headings and cross reference with the compass now and again. It is significant when you are discovering new airfields and naming them that you give the magnetic and not true bearings. Case in point Altona is 09/27 not 06/24. Another point worth mentioning ATC and or ground control at a fly-in sometimes will tell to to fly a certain bearing. This will always be magnetic.
Greg Perkins
- gertcoetzee
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I agree, for bearing and naming runways magnetic is the answer. I was wrong in giving true headings for naming the runways. However, for the position of a runway, true is the answer - since this is also the coordinate you will use when finding or marking a runway on a map, or when doing your calculations the way I was taught (prior to correcting for magnetic variation).
As for GPS - I use it to record my track mostly, and fly VFR with a map strapped to my knees.
I sometimes give myself admirable advice, but I am incapable of taking it.
:D
As for GPS - I use it to record my track mostly, and fly VFR with a map strapped to my knees.
I sometimes give myself admirable advice, but I am incapable of taking it.
:D
- Junkie
- The sky is all mine
- Posts: 455
- Joined: Tue May 24, 2005 9:01 am
- Location: Killed in microlight accident 23rd December 2006
ahhhh dont be so hard on yerself... we still luv ya anyway Gert..
who else woulda come up with all the minboggling technicolor stuff - moorse impressive.
..u mighta guessed some of us oldies struggling with all this new fangled gadgetry



..u mighta guessed some of us oldies struggling with all this new fangled gadgetry




J.U.N.K.I.E 's
Finest used aviation parts in all the Universe
No credit / No returns
Finest used aviation parts in all the Universe
No credit / No returns
- Cloud Warrior
- Top Gun
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- grosvenor
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You should always fly on magentic headings for another reason. Flight levels are determined in two sectors 0-179 degrees and 180 degrees to 359 degrees, based on magnetic track. (Semi-circular rule.) For 0-179 degrees you would be flying odd flight levels +500 feet and for 180-359 degrees you would be flying even flight level +500 feet (VFR flights). And with a 20 degree variance between magnetic and true, you could end up flying the wrong flight level for the track you are on.
Eg. You plot your course from A to B on your map. It's 355 deg True. If you have the semi-circular rule wrong, you might then decide to fly at FL085 (thinking 180 - 359 = even + 500ft). Another pilot, flying from B to A measures the true track as 175 deg, but correctly adds the Mag variation (say 20deg W) to give him a magnetic track of 195 deg. Based on the semicircular rule, he flies at FL085. You are flying in exactly the opposite direction to each other, following your GPS track exactly, and both have your altimeters set on 1013mb because you are flying a flight level. You are at exactly the same altitude coming at each other. Bad idea! And remember, you should be flying on a flight level when you fly more than 1500 ft agl.
The same applies to flying under the Jhb TMA, 270 - 089 deg magnetic, fly at 7500ft, 090 - 269 deg magnetic, fly at 7000ft.
Here endeth the nav lesson.
Dave
Eg. You plot your course from A to B on your map. It's 355 deg True. If you have the semi-circular rule wrong, you might then decide to fly at FL085 (thinking 180 - 359 = even + 500ft). Another pilot, flying from B to A measures the true track as 175 deg, but correctly adds the Mag variation (say 20deg W) to give him a magnetic track of 195 deg. Based on the semicircular rule, he flies at FL085. You are flying in exactly the opposite direction to each other, following your GPS track exactly, and both have your altimeters set on 1013mb because you are flying a flight level. You are at exactly the same altitude coming at each other. Bad idea! And remember, you should be flying on a flight level when you fly more than 1500 ft agl.
The same applies to flying under the Jhb TMA, 270 - 089 deg magnetic, fly at 7500ft, 090 - 269 deg magnetic, fly at 7000ft.
Here endeth the nav lesson.

Dave
- grosvenor
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True and Magnetic only applies to a track or heading. A co-ordinate is a fixed position and magnetic variation has no effect on it.gertcoetzee wrote:However, for the position of a runway, true is the answer - since this is also the coordinate you will use when finding or marking a runway on a map
Some trivia for you. When I did my licence 14 years ago, Durban International (Louis Botha) runway heading was 05/23. 14 years later, the co-ordinates of the runway haven't changed, and the runway hasn't changed, but the heading is now 06/24. What has changed (other than its name) is the magnetic variation. So the true heading of the runway is still the same, but the magnetic heading has changed because the lines of magnetic variation around the world shift continuously.
Dave
Here we go again, Cloud Warrior, I'll let you know, lightey, that we toppies are quite familier with GPS's. They're those square black things that need to be switched on, rightCloud Warrior wrote:"u mighta guessed some of us oldies struggling with all this new fangled gadgetry"
I didn't say nuthing! Nudge nudge wink wink hey Morpheus!


Greg Perkins
- gertcoetzee
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All this true magnetic GPS talk got me worried. Did the bit from FAMY to Porterville by map and magnetics and despite some swerves to get away from rotors thrown by Kasteelberg and later at Porterville, think I stayed OK on track. But then, I know the area and could probably could do without either. So am looking forward to a task set by the pro-map/mag guys in Western Cape. Got all day tomorrow and the weekend for flying, so fire away.

View all my logs at
http://www.zu-dve.com/

View all my logs at
http://www.zu-dve.com/
Last edited by gertcoetzee on Thu Oct 13, 2005 3:39 pm, edited 1 time in total.
- gertcoetzee
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Last edited by gertcoetzee on Thu Oct 13, 2005 3:38 pm, edited 2 times in total.
- DarkHelmet
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- gertcoetzee
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Sunday 2005-01-25
It's the most exciting thing you have ever done with your pants on!
 Stephen Coonts, 'Flight of the Intruder'
Today's Log:

It's the most exciting thing you have ever done with your pants on!
 Stephen Coonts, 'Flight of the Intruder'
Today's Log:

Last edited by gertcoetzee on Thu Oct 13, 2005 3:40 pm, edited 3 times in total.
- gertcoetzee
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- DarkHelmet
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- Location: Jukskei Park - Randburg
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