VOR Navigation RV-6A vs. Maule

[Guest]

Ok, after reading that link (thanks for that btw), I think my question should have been:

 

In what scenarios would you have separate headings selected for the heading bug and the course selector?

 

The heading is simply a reminder while the course selector (or OBS) is used to set and lead you to the desired (radial of a) VOR or ILS. Only with an autopilot the heading selector would become really usefull (to tell the ap where to head in heading mode)!

 

An example of using the heading bug could be flying an approach with a procedure turn. Let's say you have to land on runway 90. The approach plate shows you the initial approach fix is 6 miles straight out and you have to fly a heading of 270 (FROM, outbound) before making the procedure turn. The approach plate also tells you the turn should be made with a heading of 315.

 

So... you set the CDI to a course of 270 (to keep you centered for the first outbound part of the approach) and you set the heading bug to 315, simply to remind you in which heading you have to make the procedure turn. After intercepting the 270 radial at the IAF and flying outbound for three minutes you don't have to think again about which direction you have to turn: the heading bug reminds you of that.

 

After two minutes you turn left to get back to the 270 radial: you simply turn until the heading bug is at the exact opposite bottom of the gauge: this way you know you are flying back in the desired direction (which always is the opposite of the heading in which you started the turn) without having to look at the chart or calculate the desired heading.

 

In the meantime you have set the OBS to a course of 090 (TO) for the landing and you proceed until the needle centers and you are on course for the landing.

 

Just an example...

[RoboRay 126]

Ok, after reading that link (thanks for that btw), I think my question should have been:

 

In what scenarios would you have separate headings selected for the heading bug and the course selector?

 

Well, I used it recently in Flight to mark a departure course to fly from an airport that didn't have a VOR nearby. This was in bad weather at night, so visibility was poor. I needed to fly between two sets of mountains and then intercept a VOR radial toward my destination. I looked at my sectional chart to plot the course that would keep me roughly centered between the mountains and set the HDG Bug to that heading. I rotated the CDI to the VOR radial so that it would begin centering as I cleared the mountains and I could turn to my desired course.

[enamel 4]

Thanks for the examples guys, makes perfect sense.

[Great Ozzie 101]

Just a word of caution.

 

When flying a Procedure Turn, "The maneuver must be completed within the distance specified in the profile view" (AIM 5-4-9). Typically this is 10nm.

 

What is taught for timing (typically) is:

 

If the NAVAID is on the field, time outbound for 2 Minutes after station passage, then start your PT.

 

If the NAVAID is located off of the field, time outbound for 1 Minute.

 

The outbound PT leg is 1 Minute.

 

What is important (critical) is to remain within the protected airspace.

[DeferredChief 0]

Brilliant. Thanks for solving this for me!

[Guest]

Just a word of caution.

 

When flying a Procedure Turn, "The maneuver must be completed within the distance specified in the profile view" (AIM 5-4-9). Typically this is 10nm.

 

What is taught for timing (typically) is:

 

If the NAVAID is on the field, time outbound for 2 Minutes after station passage, then start your PT.

 

If the NAVAID is located off of the field, time outbound for 1 Minute.

 

The outbound PT leg is 1 Minute.

 

What is important (critical) is to remain within the protected airspace.

 

Thanks for that: I see I indeed made a mistake. My 'three minutes' should have been two and my 'two minutes' should have been one. I learned all about those plates and approaches from this great site: http://www.navfltsm.addr.com/ndb-appr.htm and it also speaks about 2 and 1 minute. So my bad. Don't know why I turned that into 3 and 2...

 

I wonder though: afaik you need to start timing at the IAF and not necessarily 'after station passage' because more often the IAF is NOT right above the VOR station. Usually it's an intersection of two VOR radials or at a certain distance from a VOR. And in that case it doesn't matter if the VOR is off field or not... Or am I missing something here?

 

It's great learning about all this stuff!!! Your "align the Lubber Line with the Course Deviation Bar"-tip was also a very nice one!

[Great Ozzie 101]

afaik you need to start timing at the IAF and not necessarily 'after station passage' because more often the IAF is NOT right above the VOR station.

 

For U.S. - Probably "PT Fix" would be the best term (found in the FAA Instrument Procedures Handbook p. 5-38 http://www.faa.gov/l...dures_handbook/ )

 

I use IAF too... but didn't like using it here as it is not quite precise enough. You can have several IAFs on an approach chart, some on course, others off (think DME arc) none requiring a PT.

 

So when I say "Station Passage" that could also be an NDB. Approaches I typically flew were like this... however a DME fix can be used as a Back Course FAF (and the IAF where a PT would be required). And you are right... Timing would begin at that DME fix.

 

Usually it's an intersection of two VOR radials or at a certain distance from a VOR

 

Ok Jeroen... a challenge for you. Show me an approach chart that defines an IAF using intersection of two VOR radials AND requires a PT. Not a hold, mind you, that is used in lieu of a PT.

 

It's great learning about all this stuff!!!

 

I'm right there with you... I thoroughly enjoy the learning and especially sharing info that y'all find helpful...

 

Rob

[Guest]

Ok Jeroen... a challenge for you. Show me an approach chart that defines an IAF using intersection of two VOR radials AND requires a PT. Not a hold, mind you, that is used in lieu of a PT.

 

LOL Fun challenge! But I see what you mean: the IAF's I was thinking about do show an intersection but more as some sort of double check option, because the IAF that leads to a PT is always simply on a noted distance of the VOR on the radial you use for landing... Examples:

 

http://155.178.201.160/d-tpp/1204/00777VTGA.PDF

 

http://155.178.201.160/d-tpp/1204/00776IL35.PDF

 

http://155.178.201.160/d-tpp/1204/00776VT35.PDF

 

All other IAF's that are a real intersection and which are not on the final course radial (or however you call that) are followed by an ARC or show NoPT... Still... the pdf's I posted DO show the IAF as an intersection too...

[Brett_Henderson 5]

Neat thread/disussion ...

[Great Ozzie 101]

Fun Challenge!? Bah! You already have seen these! :Big Grin:

 

the IAF's I was thinking about do show an intersection but more as some sort of double check option, because the IAF that leads to a PT is always simply on a noted distance of the VOR on the radial you use for landing

 

And I had to really think hard and do a little research to be sure the crossing radial could be used to define the fix. Since the Approach Chart does not say "VOR/DME" or "DME Required"... the crossing radial should be a legitmate way to identify the fix.

 

All other IAF's that are a real intersection and which are not on the final course radial (or however you call that)

 

"Final Approach Course" sound good?

 

Also "PT Fix" seems to be the correct terminology as I found another reference to it in the "Legends and General Information" for the Terminal Procedures Publication (http://aeronav.faa.g.../frntmatter.pdf LEGEND - Profile View page).

[Guest]

Fun Challenge!? Bah! You already have seen these! :Big Grin:

 

LOL I recently downloaded ALL Hawaiian approaches that could be of use in Flight. I've got 32 printed and all beside my Flight PC.

 

And I had to really think hard and do a little research to be sure the crossing radial could be used to define the fix. Since the Approach Chart does not say "VOR/DME" or "DME Required"... the crossing radial should be a legitmate way to identify the fix.

 

Aha!!! Didn't think of that. The distances are shown on the chart but when it doesn't say specifically DME is required the IAF is indeed a 'real' intersection!

 

"Final Approach Course" sound good?

 

Sounds perfect.

 

Also "PT Fix" seems to be the correct terminology as I found another reference to it in the "Legends and General Information" for the Terminal Procedures Publication (http://aeronav.faa.g.../frntmatter.pdf LEGEND - Profile View page).

 

That's a great pdf! A nice addition to the link I posted earlier in this topic! Thanks!