Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

Vor appch altitude

Wikiposts
Search
Tech Log The very best in practical technical discussion on the web

Vor appch altitude

Thread Tools
 
Search this Thread
 
Old 16th Aug 2010, 20:14
  #1 (permalink)  
Thread Starter
 
Join Date: Dec 2006
Location: Ireland
Posts: 13
Likes: 0
Received 0 Likes on 0 Posts
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?
leebrensten is offline  
Old 17th Aug 2010, 18:08
  #2 (permalink)  
Thread Starter
 
Join Date: Dec 2006
Location: Ireland
Posts: 13
Likes: 0
Received 0 Likes on 0 Posts
No clues?!
leebrensten is offline  
Old 17th Aug 2010, 20:07
  #3 (permalink)  
 
Join Date: Mar 2000
Location: Arizona USA
Posts: 8,571
Likes: 0
Received 0 Likes on 0 Posts
Post the procedure, and ...you will be informed.
Simples.
411A is offline  
Old 17th Aug 2010, 21:01
  #4 (permalink)  
 
Join Date: Jul 2006
Location: self isolating
Posts: 1,313
Likes: 0
Received 10 Likes on 3 Posts
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)

EpsilonVaz is offline  
Old 17th Aug 2010, 22:05
  #5 (permalink)  
Moderator
 
Join Date: Apr 2001
Location: various places .....
Posts: 7,193
Received 101 Likes on 68 Posts
(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.
john_tullamarine is offline  
Old 18th Aug 2010, 00:27
  #6 (permalink)  
 
Join Date: Apr 2008
Location: Oz
Posts: 306
Received 0 Likes on 0 Posts
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.
clark y is offline  
Old 18th Aug 2010, 01:20
  #7 (permalink)  
Guest
 
Join Date: Apr 2009
Location: On the Beach
Posts: 3,336
Likes: 0
Received 0 Likes on 0 Posts
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.
aterpster is offline  
Old 18th Aug 2010, 03:08
  #8 (permalink)  
Moderator
 
Join Date: Apr 2001
Location: various places .....
Posts: 7,193
Received 101 Likes on 68 Posts
Whew .. that's a relief .. I had visions of the US folks coming after me with guns all a-blazin'.
john_tullamarine is offline  
Old 27th Aug 2010, 21:07
  #9 (permalink)  
 
Join Date: Feb 2000
Location: uk
Posts: 21
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by clark y
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
Grond is offline  
Old 28th Aug 2010, 06:47
  #10 (permalink)  
 
Join Date: May 2008
Location: Euroland
Age: 53
Posts: 152
Likes: 0
Received 0 Likes on 0 Posts
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
.
.
Edit:
Approach transition inset. Provided when route originates at an off-chart intersection designated only for approach chart use.
.
.

Last edited by bArt2; 28th Aug 2010 at 07:15.
bArt2 is offline  
Old 28th Aug 2010, 06:54
  #11 (permalink)  
Per Ardua ad Astraeus
 
Join Date: Mar 2000
Location: UK
Posts: 18,579
Likes: 0
Received 0 Likes on 0 Posts
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?
BOAC is offline  
Old 28th Aug 2010, 08:58
  #12 (permalink)  
 
Join Date: May 2009
Location: Ireland
Age: 42
Posts: 21
Likes: 0
Received 0 Likes on 0 Posts
Does the 1100T mean that after BAPDA you can descend to 1100? Is this indicated on the vertical profile?
Balkanhawk is offline  
Old 28th Aug 2010, 10:45
  #13 (permalink)  
 
Join Date: Aug 1998
Posts: 167
Likes: 0
Received 0 Likes on 0 Posts
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.
minuteman is offline  
Old 28th Aug 2010, 11:55
  #14 (permalink)  

Only half a speed-brake
 
Join Date: Apr 2003
Location: Commuting not home
Age: 46
Posts: 4,321
Received 3 Likes on 3 Posts
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)
FlightDetent is offline  
Old 28th Aug 2010, 23:34
  #15 (permalink)  
 
Join Date: Feb 2000
Location: uk
Posts: 21
Likes: 0
Received 0 Likes on 0 Posts
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 ....
Grond is offline  
Old 29th Aug 2010, 01:59
  #16 (permalink)  
 
Join Date: Dec 2002
Location: Where the Quaboag River flows, USA
Age: 71
Posts: 3,415
Received 3 Likes on 3 Posts
BOAC

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

GF
galaxy flyer is online now  
Old 29th Aug 2010, 08:12
  #17 (permalink)  
 
Join Date: May 2008
Location: Euroland
Age: 53
Posts: 152
Likes: 0
Received 0 Likes on 0 Posts
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.
bArt2 is offline  
Old 29th Aug 2010, 11:33
  #18 (permalink)  
 
Join Date: May 2009
Location: Ireland
Age: 42
Posts: 21
Likes: 0
Received 0 Likes on 0 Posts
I figured that, why do they bother displaying it then? Is it because it is technically part of the arrival?
Balkanhawk is offline  
Old 29th Aug 2010, 14:08
  #19 (permalink)  
 
Join Date: Jun 2009
Location: US
Posts: 497
Likes: 0
Received 0 Likes on 0 Posts
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.
p51guy is offline  
Old 29th Aug 2010, 18:53
  #20 (permalink)  
Guest
 
Join Date: Apr 2009
Location: On the Beach
Posts: 3,336
Likes: 0
Received 0 Likes on 0 Posts
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.

aterpster is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.