I remember the same DH/MDA usage on the A320. At some point (I think with the LCD upgrade) they switched to "BARO" and "RADIO" instead, which in my opinion is the better choice. The checklist would then only mention "minimums", though I actually have seen "MDA/DA/DH" in an actual airline checklist.
Captain, i came upon your channel by the random UA-cam suggestion. You are an exceptional instructor. I truly hope i get to fly with you someday Captain. Soaring Skies.
Great video, I didnt know MDA was used for ILS cat 1. Small correction, the inner knob is used to set the value, the outer knob is used to set DH/MDA. Thanks for your work.
Thank you for your feedback. To me, the outer knob it the one that protrudes furthest out from the panel. But ATR is French, and the French have a tradition of doing things the opposite way.
Another comment regarding DH, at 4:59 you mention “nobody has measured the elevation of the terrain outside the airport perimeter”. However the published DH on a Cat 1 approach chart is the height above terrain at the published MDA (so not in reference to the runway threshold). I believe the terrain elevation is taken into account, let me know what you think, Thanks
"... with this in mind." Published DH is the height above the runway threshold, and not the terrain. By regulation, DH cannot be less than 200 feet on a Cat 1 approach. However, the required terrain clearance is less than 200 feet and depends on aircraft category. In AIP, ILS cat 1 minima is published as OCH, which is the "allowance used by the procedures specialist for vertical displacement during initiation of a missed approach." For ATR (category B), the value is 142 feet. The computation method is quite complex; it's described in PANS OPS volume 2. The terrain outside the airport perimeter is checked for obstacles that can affect approach minima, location of the landing runway threshold, and the required climb gradient after take-off.
In ATR aircraft, DH means radio altimeter, and MDA means barometric altimeter. Boeing is using RADIO/BARO, which is more correct. For ILS cat II, we use the radio altimeter to define minima, which is expressed as DH. All other minima are defined with the barometric altimeter: 3D approaches (ILS cat I, LNAV/VNAV) are defined with DA. A missed approach can be initiated at DA. 2D approaches ((LOC, VOR, LNAV, NDB) are defined with MDA. A missed approach must be initiated at MDA plus 30 or 50 feet to prevent the aircraft from descending below MDA.
Hi Mr Magnar. Can you tell me where to find this on the ATR 72-500? I can change the DH if i use some keys in my simulator but i can' find the switch / knob in the 3d cockpit. Thank you :)
@@FlywithMagnar I noticed that the video is about the 600, that's why i asked for the 500 :) After i read your replay, i watched fast through your "ATR systems - EFIS instrument panel part 1" video and found the answer. This function is sadly missing in the Aerosoft ATR 72-500 but now i know to wich knob i have to add this function if i build my home cockpit :) Thank you very much.
I remember the same DH/MDA usage on the A320. At some point (I think with the LCD upgrade) they switched to "BARO" and "RADIO" instead, which in my opinion is the better choice. The checklist would then only mention "minimums", though I actually have seen "MDA/DA/DH" in an actual airline checklist.
Agree. BARO and RADIO make more sense. I'm pretty sure ATR will follow suit.
Captain, i came upon your channel by the random UA-cam suggestion.
You are an exceptional instructor. I truly hope i get to fly with you someday Captain.
Soaring Skies.
Welcome onboard!
Thank you Magnar for the DH/MDA clarification and implications. Much appreciated!
Great video, I didnt know MDA was used for ILS cat 1. Small correction, the inner knob is used to set the value, the outer knob is used to set DH/MDA. Thanks for your work.
Thank you for your feedback. To me, the outer knob it the one that protrudes furthest out from the panel. But ATR is French, and the French have a tradition of doing things the opposite way.
Future ATR42/73 FO here, superb videos, so helpful, thanks a lot sir.
what FT organisation are you undergoing TR training if any?
what does FT and Tr mean ?
FT = Flight Training. In EASA, it's called Approved Training Organization, ATO.
TR = Type Rating.
@@zaharbj8594 with my company, then sim at CAE Montreal
Thank you for the explanation capt! Safe skies always!
Great video ! Thank you !
Just as an added point, from the 200 call to minimums on the Cat 2 was just over 6 seconds, less than you'd expect for flat terrain.
Tack Magnar !
Thanks for share the videos are very helpfull for the instruction
Looking great in that shirt Nadar!
Beautiful landing.
Interesting, using MDA as DA for CAT 1 ILS.
Many thanks Captain
dhdadha :'D
love it :)
good job!
Another comment regarding DH, at 4:59 you mention “nobody has measured the elevation of the terrain outside the airport perimeter”. However the published DH on a Cat 1 approach chart is the height above terrain at the published MDA (so not in reference to the runway threshold). I believe the terrain elevation is taken into account, let me know what you think, Thanks
"... with this in mind."
Published DH is the height above the runway threshold, and not the terrain. By regulation, DH cannot be less than 200 feet on a Cat 1 approach.
However, the required terrain clearance is less than 200 feet and depends on aircraft category. In AIP, ILS cat 1 minima is published as OCH, which is the "allowance used by the procedures specialist for vertical displacement during initiation of a missed approach." For ATR (category B), the value is 142 feet. The computation method is quite complex; it's described in PANS OPS volume 2.
The terrain outside the airport perimeter is checked for obstacles that can affect approach minima, location of the landing runway threshold, and the required climb gradient after take-off.
What is your Roster this weekend?
Hi CAPT Magnar, ILS cat 1 using MDA ,is it valid for another aircraft .? As I know Precision app use DH, non precision app use MDA
In ATR aircraft, DH means radio altimeter, and MDA means barometric altimeter. Boeing is using RADIO/BARO, which is more correct.
For ILS cat II, we use the radio altimeter to define minima, which is expressed as DH.
All other minima are defined with the barometric altimeter:
3D approaches (ILS cat I, LNAV/VNAV) are defined with DA. A missed approach can be initiated at DA.
2D approaches ((LOC, VOR, LNAV, NDB) are defined with MDA. A missed approach must be initiated at MDA plus 30 or 50 feet to prevent the aircraft from descending below MDA.
Hi Mr Magnar. Can you tell me where to find this on the ATR 72-500? I can change the DH if i use some keys in my simulator but i can' find the switch / knob in the 3d cockpit. Thank you :)
The video is about the 600 version with glass cockpit. On the 500, the DH is set on the EFIS Control Panel, and there's no option for MDA.
@@FlywithMagnar I noticed that the video is about the 600, that's why i asked for the 500 :) After i read your replay, i watched fast through your "ATR systems - EFIS instrument panel part 1" video and found the answer. This function is sadly missing in the Aerosoft ATR 72-500 but now i know to wich knob i have to add this function if i build my home cockpit :) Thank you very much.