Charts will have mins usually published on both radio and baro altitude. At high elevation airports like DEN I use radio, at low elevation airports I use baro.

Charts will have mins usually published on both radio and baro altitude. At high elevation airports like DEN I use radio, at low elevation airports I use baro.

Should that not be the other way around?

radio altitude (RA) can only be used if published on the approach charts.

Several chart providers exist, but I assume they all indicate radio altitude minimus with "RA".

 

These are very exact numbers and take into account even the sligthest uneveness in terrain.

I am looking at the ILS 16 into Zurich LSZH at the moment.

You would think the Cat II approach for this runway would have a RA of 100ft.

But it does not.

It reads 93ft.

Why...because those 100ft minimus (standard cat II minimums) are measuered above Threshold elevation. When you are 100ft height above the threshold you have to see the runway or go around. And when you are 100ft above the threshold you are about 1/3nm from the threshold, and right below you at that position there happens to be a little pile of dirt that makes your radioaltimeter read 93ft :-)

 

So, when you are using published baro minimums (lets take 200ft baro for example) and convert them to an above ground height and dial that into your RA....then you might get that (200ft RA) read out way earlier if you pass over a hill somewhere during the approach. And you would innitiate an unnecessary go around.

Or...worse case....if the runway is on top of a hill....you would not get a 200ft RA readout anywhere before the threshold! You would bust your minimums and go down dangerously low!

 

So, only use RA when published!

(In real life that is...ofcourse while simming you can do as you please :-) )

 

Then there are those other values that are published next to your baro minimums.

200 - 550

What are those?

They are not values to put into your RA!

 

Zurich for example has a Cat I Baro minima of 1590ft Baro.

Zurichs elevation is 1390ft

1390 + 200ft = 1590ft

Yes, but you can not put 200ft in your RA and fly it like that (see above).

Those 200 - 550 are your weather minima!

When you read a weather report (Metar or TAF) the cloud bases in there are AGL (above ground).

So if you want to go to Zurich and are allowed to fly no lower than Cat I minimums with your equipment or your certification (I know the 777 is Cat IIIB but not all aircraft are) then you need a cloud base of 200ft AGL and a visibility of 550 meters.

 

LSZH 030100Z 160/15 0800 FG BKN003 10/9 1013 is good.

800m visibility and the cloud base is 300ft above ground :-)

 

LSZH 030100Z 160/15 0800 FG BKN001 10/9 1013 is Not good!

800m visibility is ok, but you cant plan with that airport as the cloud base is only 100ft above ground.

For an ILS CAT I approach which is what you would use most of the time, you have to set your minimums (BARO) always, whatever minimums or DA appear in your chart... For instance in the ILS app chart to rwy 01 at Guatemala, you have to set a minimums (BARO) of 5100.

 

 

Should that not be the other way around?

It certanly is

Captain and F/O minimums baro or radio must be set both together in order to hear the minimums callout.

It is my understanding that you read from the chart the class/category of landing (A, B, C) then add 50ft to the altitude in the relative box and that's your "Baro" setting (MDA).

Correct?

 

Edit: In addition, it is my understanding that at this altitude call-out that the pilot flying verbally indicates his intention (Land or not).

 

 

Kyle: "Legal" was indeed a wrong choice of words on my part... "Procedurally" would have been better.

 

Just figured I'd point it out.

 

 

 

radio altitude (RA) can only be used if published on the approach charts.

 

As I pointed out earlier, as far as I know (FAA side only), there's no regulatory requirement to use one or the other.

 

That being said, though, it would be improper to use baro when RA is displayed and vice versa, for exactly the reasons you mentioned.  RA is only checked for accuracy when it is displayed on the chart.

 

 

 

Captain and F/O minimums baro or radio must be set both together in order to hear the minimums callout.

 

Only the captain side:

FCOMv2 15.10.16

Captain and F/O minimums baro or radio must be set both together in order to hear the minimums callout.

 

Nop, i tested it yesterday, setting only the capt radio you can hear the callouts

Hello pilots!

 

I was checking the chart from KDEN and say that RAD is required So I assume that you should use RAD instead BAR (see the screenshot)

 

I also have a stupid question, where I can find the minimum altitude in the chart? I think the Runway 16R is 200 RAD but I can't find it, or may be I'm looking in the wrong chart

 

Where I can find the minimum altitude ?

 

Thanks for your answer

 

 

 

 

Mauricio

Hello pilots!

 

I was checking the chart from KDEN and say that RAD is required So I assume that you should use RAD instead BAR (see the screenshot)

 

I also have a stupid question, where I can find the minimum altitude in the chart? I think the Runway 16R is 200 RAD but I can't find it, or may be I'm looking in the wrong chart

 

Where I can find the minimum altitude ?

 

Thanks for your answer

 

kden.png

 

 

Mauricio

 

That's not what you think it means

 

You would find the number in the boxes at the bottom

 

For example baro would be 5530 and radio would be 200

That's not what you think it means

 

You would find the number in the boxes at the bottom

 

For example baro would be 5530 and radio would be 200

 

Thanks for your answer Man

 

Then Is my choice if I use Baro or Radian?

 

I mean I have the numbers there in the chart 5530/200, Can I use either?

 

Regards

Thanks for your answer Man

 

Then Is my choice if I use Baro or Radian?

 

I mean I have the numbers there in the chart 5530/200, Can I use either?

 

Regards

No you can not. And I am a bit surprised this question comes up in this thread again since I already explained in greath length in post #18 why not.

No you can not. And I am a bit surprised this question comes up in this thread again since I already explained in greath length in post #18 why not.

 

Opps sorry I will check that :blush:

Hello pilots!

 

I was checking the chart from KDEN and say that RAD is required So I assume that you should use RAD instead BAR (see the screenshot)

 

I also have a stupid question, where I can find the minimum altitude in the chart? I think the Runway 16R is 200 RAD but I can't find it, or may be I'm looking in the wrong chart

 

Where I can find the minimum altitude ?

 

Thanks for your answer

 

kden.png

 

 

Mauricio

 

That is short for RADAR REQUIRED (as it is notated on the FAA charts, not sure why they couldn't fit 2 more letters on there on yours..) which means that in the real world you have to be in contact with ATC and be in radar contact to execute this procedure.