Jump to content

What do all the different altitudes in charts mean?


Recommended Posts

Hi there, I have been using Navigraph Charts for a while now and I had always wondered what 4 little numbers on every chart mean. I think they are altitudes but they are all different.

 

The first one says "AD ELEV "Number" It is on the bottom left on an ILS approach runway chart and it's next to a compass

ex: AD ELEV 96

Example

 

The second one is a number on a little runway next to the runway length and next to a letter G which I believe stands for the glideslope

ex: 46 G 2743

Example

 

The Third one is on the same little runway diagram and is a number followed by the letters "HL"

ex: 60 HL

      15 HL

Example

 

And the last one is a bolded number followed by a slash and a number hPa

ex: 90 / 3hPa

Example

 

Thanks so much,

 

Ardalan

Link to post
Share on other sites

It would help to know what country's charts you're referring to and if you could, please provide a link to the chart you are referring to.  Aeronautical charts vary greatly from country to country and since approach charts are entirely within a single country's jurisdiction, they are the most variable.  What you know about the charts in one country may not help you much in another, even though there are some international standards that apply.

 

I can shed a little light on these...

 

AD ELEV 96: Aerodrome Elevation, in feet MSL (above Mean Sea Level)

 

90 / 3 hPa:  hPa is a unit of pressure, namely hectoPascals, equivalent to one millibar, or a thousandth of a bar.  The mean sea-level Atmospheric Pressure is 1013, at a standard temperature of 20° Celsius.  It appears that the 3 hPa is given as an equivalent of the pressure change in 90 feet of elevation.  I'm guessing it's a guide to setting an altimeter at an airport with an elevation of 90' MSL.  An altimeter can be set using a known height above sea level or a pressure, most often in inches of mercury but sometimes in other systems of measurement.  

Link to post
Share on other sites
Quote

The second one is a number on a little runway next to the runway length and next to a letter G which I believe stands for the glideslope ex: 46 G 2743

 

2743 is the length in meters of Runway 17L/35R at KMCO, i.e. 9,000' (all the others are longer).  I'm not seeing that G annotation on any of my KMCO approach plates but my set dates from 2011 and are FAA charts.  I think yours must be from a different source, given the metric annotations.

 

John

Link to post
Share on other sites

It's possible but the field elevation is more like 90 (96 in FSX).  It's a big field physically and there could be that much variation from runway to runway, so that's possible but without seeing the actual plate it's hard to know for sure, and maybe not even then.  Somebody knows.

 

John

Link to post
Share on other sites

I'm thinking the #46 would be the width of the runway in meters (150') and the G could mean the runway is grooved since they are all in the same location as the runway length. Just a guess at this point.:)

Link to post
Share on other sites
  • 4 weeks later...

Just saw this and can shed some lights.

 

John got already got AD covered, and the pressure stuff I have no idea on.

 

As for the 46 G 2743 bit John and Brett combined gives the answer. Width, Grooved (x for ungrooved) and finally available landing distance.

 

So that leaves me with the 60 HL/15 HL bit.

 

It's type of lights and Spacing for edge- and centerline lights respectively..

 

Types are H (high), M (medium), L (low), HL (variable High to Low) or ML (variable Medium to Low).

 

If you need more information on reading the LIDO-charts, take a look at this handy little 106 page guide.

 

https://www.ivao.aero/training/documentation/books/understand_lido_charts.pdf

 

  • Like 1
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...