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Vor appch altitude

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Vor appch altitude

Old 16th Aug 2010, 20:14
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Vor appch altitude

Hi, was looking at VOR 16 Dublin, and under the 3000 feet interception alt on the plan view is 1100t. Is this the moca for the procedure?
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Old 17th Aug 2010, 18:08
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No clues?!
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Old 17th Aug 2010, 20:07
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Post the procedure, and ...you will be informed.
Simples.
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Old 17th Aug 2010, 21:01
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I take it you mean this?

(Not sure if I'm allowed to post Jepp plate on here, so I cut it in half and drew on it)

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Old 17th Aug 2010, 22:05
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(Not sure if I'm allowed to post Jepp plate on here, so I cut it in half and drew on it)

Caveat - I have no legal competence.

However, my limited understanding on copyright is that one can copy limited exerpts from a copyright document for review, research, etc.

Until/unless one of the legal folk further up the totem pole tells me otherwise, I have no problem with a one-off post of (a) copyright document exerpt(s) for appropriate purposes in the forum.

Mind you, I thought that the smiley face was rather cute.
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Old 18th Aug 2010, 00:27
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Leebrensten,

It is the MOCA.

I've asked a Jepp rep. to explain the difference between the two altitudes. His reply was that the 3000' is where the profile/3 degree slope starts (constant angle) where as the 1100T is the lowest you can go if you choose to "dive and drive".

So the profile on the chart should show the DME/ optimum altitude from 3000'.


Clark y.
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Old 18th Aug 2010, 01:20
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John T:

However, my limited understanding on copyright is that one can copy limited exerpts from a copyright document for review, research, etc.
It's "fair use" under US copyright law. Besides, Jeppesen just does not get excited over snippets to make a point.
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Old 18th Aug 2010, 03:08
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Whew .. that's a relief .. I had visions of the US folks coming after me with guns all a-blazin'.
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Old 27th Aug 2010, 21:07
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Originally Posted by clark y View Post
Leebrensten,

It is the MOCA.

I've asked a Jepp rep. to explain the difference between the two altitudes. His reply was that the 3000' is where the profile/3 degree slope starts (constant angle) where as the 1100T is the lowest you can go if you choose to "dive and drive".

So the profile on the chart should show the DME/ optimum altitude from 3000'.


Clark y.
I don't doubt what you say which is my interpretation of the plate as well. But could you ask your Jeppy rep exactly where in their manuals is this explained. We could not find anything in the chart legends which explains the terminology used on this chart.

I think 1100 ft is also the height which is the lowest to use if your sole means of navigation is by reading road signs. It would certainly raise a few eyebrows
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Old 28th Aug 2010, 06:47
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From the Jeppesen introduction section (abbreviations):

T - Terrain clearance altitude (MOCA)
From the Jeppesen introduction section (enroute chart legend):

1300T - MOCA (minimum obstruction clearance altitude)
Nothing mentioned in the approach chart legend though.

Looking at the chart again it makes sense that you have too look for it in the enroute chart legend. It is located inside the dashed box and indicates a section of the arrival and is not part of the approach section, although the IAF is within the dashed box. Maybee I have to check the introduction section again
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Edit:
Approach transition inset. Provided when route originates at an off-chart intersection designated only for approach chart use.
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.

Last edited by bArt2; 28th Aug 2010 at 07:15.
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Old 28th Aug 2010, 06:54
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An interesting 'approach' in view of the fear with which US pilots view MSA - it it 'safe? Is it useable OUTWITH emergencies? Is it regularly updated/surveyed? In fact is it any use at all, being below MSA?
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Old 28th Aug 2010, 08:58
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Does the 1100T mean that after BAPDA you can descend to 1100? Is this indicated on the vertical profile?
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Old 28th Aug 2010, 10:45
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From my Jeppesen intro:

MINIMUM OBSTRUCTION CLEARANCE ALTITUDE (MOCA) The lowest published altitude in effect between radio fixes on VOR airways, off airway routes, or route segments which meets obstacle clearance requirements for the entire route segment and in the USA assures acceptable navigational signal coverage only within 22 nautical miles of a VOR.

My understanding is that it does not guarantee navaid reception at that altitude.

The precise segment you refer in the VOR 16 is an approach transition (Jepp Intro Page 105 onwards) and any or all of the enroute type altitudes (e.g. in red, with a, or T afterwards) could be described due to its "enroute" nature. The approach itself only begins at the D4.6 point.

Edit for speling.
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Old 28th Aug 2010, 11:55
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Here's the AIP version http://www.iaa.ie/safe_reg/iaip/Publ...W_24-25_en.pdf , the only true source to resolve anything. 1100A is the OCA for intermediate APCH segment.

Yours,
FD (the un-real)
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Old 28th Aug 2010, 23:34
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Well spotted bart2. You must have longer in the cruise than I do. I only have 4 hours to kill Now, what can we read next ....
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Old 29th Aug 2010, 01:59
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BOAC

US pilots don't "fear" MSA, here it is just not an operational altitude, just for emergency use, per TERPS.

GF
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Old 29th Aug 2010, 08:12
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Does the 1100T mean that after BAPDA you can descend to 1100? Is this indicated on the vertical profile?
No it just means you might dent the aircraft if you go below it. GS intercept altitude is 3000 feet so why would you descend to 1100.

Edit:
Well you can't see that the GS int alt is 3000 feet on the posted jepp chart snippet, but you can see it on the AIP chart posted by Flight Detent which was posted after your reply.
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Old 29th Aug 2010, 11:33
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I figured that, why do they bother displaying it then? Is it because it is technically part of the arrival?
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Old 29th Aug 2010, 14:08
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http://www.iaa.ie/safe_reg/iaip/Publ...W_24-25_en.pdf

On the very bottom of this chart the 1100 ft shows up on the bottom of the vertical profile.
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Old 29th Aug 2010, 18:53
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p51guy:

On the very bottom of this chart the 1100 ft shows up on the bottom of the vertical profile.
Therein lies the problem. Jeppesen didn't comply with source as to the profile view, thus the confusing 1,100T in the out-of-scale box.

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