Why is one ILS 250ft DH while another is 200ft DH
This is when both are not apparently affected by any terrain or other obstacles.
Are there some factors like the required regular calibration/survey of the 200ft one being more expensive?
Flight inspection costs are independent of DH. However, they might be different between CAT I, II and III due to different accuracy and tolerance requirements.
Nope, all the same. Can you give an example Peter?
LKPR ILS24, LFAT ILS13.
Possible offset on final track, or limited approach light system? The latter usually relates to RVR not DH.
I was waiting for one of the gurus to answer this one, but I believe that a 200 ft DH requires the runway to be CAT I certified. If the runway is only certified to “NONP”, then the minimum DH cannot be lower than 250 ft. But I do not know how a runway is certified.
Where do you get 250 ft DH from? It’s a Cat III runway with a Cat I OCH of 137 ft.
I think he means LFAT is 250ft. LKPR is 200, unless you have bells and whistle.
Ah, OK, I get it now. So the real question is “why is the LFAT ILS 13 DH 250 ft and not the more usual 200 ft system minimum?”