MDA v DH on Approach Charts

Still trying to understand. When doing an ILS precision approach, it it correct that we should use DH a/k/a Radio and not there MDA? If so, which number to you enter in there DA/RADIO? There chart for expample RUNWAY 1L for KLAS says "ILS DA/ (H) 2460’(284). Which number do you enter? The one in parenthesis?

Hello Samuel! Welcome to the forum!

While this forum is dedicated to technical support and not chart-reading guidance, I do have some good sources of information for you.

First and foremost, the FAA CFR is a great resource. In this case, you are looking for information described in CFR 14 § 1.1 - General definitions. Use your browser’s search-in-text function to find the definition related to “Decision altitude” and “Minimum descent altitude” respectively.

I can also personally recommend Again, articles of interests would be Minimum Descent Altitude/Height (MDA/MDH) and Decision Altitude/Height (DA/DH). The first one even includes exactly the comparison you are looking for, stating:

An MDA/H differs from a Decision Altitude/Height in that the aircraft must be flown in such a way that it does not descend below the MDA/H unless the required visual reference has been established. Typically, an aircraft will continue at the MDA/H until a pre-calculated missed approach point is reached; if the required visual reference is not established by that point a Missed Approach will be flown.

Lastly, giving the term “mda vs dh” a search on Google reveals multiple great resources, such as forums and blog posts, that try to shed light on this very difference. You are clearly not alone in your confusion, and I’m sure you’ll find a solution elsewhere if the above was not sufficient!

I hope this helps to get a clearer picture!

Kind Regards,