How to setup mimimum altitude

[lyxelso]

Hi guys, i need some help to set my minimum altitude for my approachs.

How do i set a minimum that is above 1000ft. i know we have to use the "baro" but then do i have to press a knob or switch something on/off to make the BARO active instead of the radio ?

Can someone give me a exemple on how to set a miminum of 2540ft.

Thanks for your help.

David. 

[Litjan]

You should use the orange bug on the altimeter to set a mimimum descent altitude, like 2540ft (non-precisicion and CAT I ILS approaches). You would set the bug to 540 feet and just memorize the "2".

The DH window is only used to set up a Descision Height, which is a height above terrain, for CATII and CATIIIa approaches. These descision heights are typically ca. 100 feet for CATII and exactly 50 feet for CATIIIa approaches.

 

Cheers, Jan

 

[lyxelso]

Thanks for your reply & your help Litjan. So there is no Callout for minimum descent altitude ? 

[Andrey Novikov]

Why no callout? It says "minimums".

[mfor]

For the barometric minimum descend altitude it's just a bug on the altimeter, so no callouts - if you use the the radar DH you get the "minimums" callout.

[Litjan]

mfor is right. If you shoot a non-precision or CAT I ILS approach, the callout "minimums" will (should) come from the pilot not flying/pilot monitoring. If you shoot a low-visibility precision approach CAT II/IIIa the minimum will come from the set DH.

Jan

 

[lyxelso]

Thank you guys for your replys.

So when performing a non-precision or CAT I ILS approach, i only use the bug on the altimeter for the minimum and set the radio to -20 i guess ?

David.

[Litjan]

Hi David, that is correct.

You "could" use the DH window (as many people do it) and set it to "200", for example. This would not be a legally correct procedure, however, as the call "minimums" would sound wheneve the radar altimeter measures "200 feet" - which may not be when the plane is actually 200 feet above the runway threshhold. Imagine there is a steept drop-off or a hill right in front of the runway.

For the CATII approaches with it´s 100 feet minimum the terrain in front of the runway is carefully charted and the RA value in the charts is adjusted accordingly (it may be displayed as RA 95, for example).

For the CATIIIa the radar alt is always 50 feet, as the plane will be above the runway at that point (and the runway is flat).

Jan