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Holds (ugh)... (Read 560 times)
Jul 16th, 2009 at 11:25am

Brett_Henderson   Offline
Colonel
EVERY OUTER MARKER SHOULD
BE AN NDB

Gender: male
Posts: 3593
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Whether it's because you're reaching the end of an instrument approach, have just popped out from the soup, looked up over the panel, and can't see anything that resembles where you'd want to land an airplane.. or it's because ATC needs for you to wait for a while  Roll Eyes  .. you're eventually gonna have to fly to a holding fix, and stay there  ..

This topic is best tackled by instructional links..  And then we can discuss and field questions, as they come up.. These are quite good.. and have neat Youtube videos..

http://www.touch-n-goes.com/articles/insrument/holdingpatterns.html

http://www.touch-n-goes.com/articles/insrument/holdentries.html

 
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Reply #1 - Jul 16th, 2009 at 11:55am

Brett_Henderson   Offline
Colonel
EVERY OUTER MARKER SHOULD
BE AN NDB

Gender: male
Posts: 3593
*****
 
For consistent reference,, we'll use the hold in the approach we've been using.

...
 
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Reply #2 - Aug 7th, 2009 at 2:45pm

Aiden327   Offline
Colonel
Hello!

Posts: 100
*****
 
I think I have the concept down with a VOR. You fly towards it and make the appropriate entrance procedure, then the second time you fly over it you make a standard rate to the proper radial. Either the assigned radial or the reciprocal depending on which direction you it it at. The vor needle will keep you on course when flying inbound to the VOR and you use your heading to fly the outbound?

However I have no clue how you would use an NDB or GPS fix. The needle only points to an ndb so would rotating the compass card to the inbound radial give you a accurate inbound course. (in a zero wind situation).

The other question I have is the video mentioned adjusting the outbound leg to the inbound legs time. How would you be able to calculate this. Is there some formula you use based on airpeed?

This is a topic I need to learn if I ever get radar contact so I don't have to disable holding Cheesy.

Aiden

EDIT: I just tried an NDB hold and I think It worked. I flew into the ndb, then back, made a standard turn to the assigned outbound and flew that with the heading indicator and flew back using the ndb. I didn't finish it because I was too excited to post this Smiley. I am flying the defualt cessna.

Besides the fact I overflew the outbound by 3x and my altitude is all over the place did I do anything wrong? http://img268.imageshack.us/img268/8563/myfirsthold.jpg

I am using the missed approach procedure from this approach. http://204.108.4.16/d-tpp/0908/00443I1.PDF
 
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Reply #3 - Aug 7th, 2009 at 3:41pm

Brett_Henderson   Offline
Colonel
EVERY OUTER MARKER SHOULD
BE AN NDB

Gender: male
Posts: 3593
*****
 
You've got the general idea  Smiley

For the sake of this thread.. it will always be a standard hold (right-hand turns), and the inbound leg will always be AT the VOR.

For zero-wind, there is no adjustment in either leg-length or heading, .. unless of course you're disoriented, simple timing will do... If you need to get your "bearings"..then you just time one leg against the other. If you arrived at the VOR too early, just lengthen the outbound leg. Of course with wind, it gets complicated, but you'll get feel for it.

Yes, you fly the outbound leg by heading (and keep an eye on the CDI, to see if you're drifting too much). You'll get a feel for how much deflection you'll need during the outbound leg. And if there's a strong X-wind, the CDI will warn you that you're drifting to the unprotected side.

The rule of thumb for X-wind; is to triple the correction you needed to stay on the inbound radial for the outbound leg.

EXAMPLE:  If the inbound leg is 270 and you had to fly 275 to stay on the radial.. then on the turn to the outbound leg triple that 5 degrees. Instead of rolling out on 090; you'd roll out on a 075 heading. If the wind is constant; your turn inbound should put you very near the 270 radial.

For NDB holds, it's a little trickier. The best way to stay on a radial, is to mentally super-impose the NDB needle onto your heading indicator, and ignore the NDB compass card all together. This technique is mentioned in my Sim Flight Training section. Some people have a mental block about doing this, so they'd have to constantly adjust the card to their heading.
 
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Reply #4 - Aug 7th, 2009 at 4:18pm

Aiden327   Offline
Colonel
Hello!

Posts: 100
*****
 
Thanks for the tips, I will try them as soon as I can. This tutorial made holding alot of sense. Now I need to work my way up to more complex aircraft. It will probably be easier with a course and heading bug.

Aiden
 
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