Illegal to start final descent after MAP?

3 Answers

1. Best Answer
   
   

   
   

   Russ Roslewski on Jan 29, 2017

   If you have reached the MAP without the runway environment (etc.) in sight, or if you don’t have the required visibility, you are expected to immediately perform the missed approach.

   ———-
   From 14 CFR 91.175:
   (e) Missed approach procedures. Each pilot operating an aircraft…shall immediately execute an appropriate missed approach procedure when either of the following conditions exist:

   (1) Whenever operating an aircraft pursuant to paragraph (c) or (l) of this section and the requirements of that paragraph are not met [seeing the runway and having the flight visibility required] at either of the following times:

   …

   (ii) Upon arrival at the missed approach point,
   ———-

   So the quick answer to your question is no, you may not go ahead and land once you’ve passed the MAP without having the necessary things in sight.

   But generally, I think this question is largely academic and is splitting hairs. For example, if you are flying an LNAV approach, most of these have the MAP at the runway threshold, and the MDA is something like 400 feet as a practical minimum. So if you get to the MAP and see the runway right then, you have to descend 400 feet to land. This is going to take about a mile if using “normal” maneuvers (as you are required to do), so it’s got to be a pretty long runway.

   However, if you didn’t see the runway until reaching the MAP, chances are nearly 100% that you therefore don’t have the minimum flight visibility required to land from the approach, which on most LNAV procedures is at least 1 mile. If you don’t see the runway until you’re on top of it, you must not have the flight visibility, and therefore can’t land anyway. Sure, you could construct a scenario where you pop out of the cloud into clear VMC right at that exact moment, but that happens only very rarely.

   Some LNAV approaches have the MAP some distance before the runway, but often the visibility minimum is increased to compensate, so you have the same situation.

   A VOR approach may have the MAP halfway down the runway, off to the side of the runway, or even past the runway if it’s based on an on-field VOR and the VOR is the MAP. So, even less likely of a situation.

   Regardless, if you don’t see the runway until the last second (let alone after the last second), that means it’s pretty murky out there. I wouldn’t trust it to stay that way during your landing, and you may very well lose sight of the runway again. So, the more reasonable solution is to go missed and go somewhere else to land (or fly a different approach with lower minimums).

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   Lemontree on Jan 29, 2017

   Thank you very much Russ. Your answer provides me another perspective into the matter. I thought of the matter only in terms of the MAP itself, and now I realize it should be considered in relation to visibility as well. Thank you.

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3. 
   

   
   

   Russ Roslewski on Jan 30, 2017

   You bet. Visibility requirements are really not often emphasized in IFR training – we talk about them, but don’t get to experience them in flight so it doesn’t sink in. This is one place where simulators have a distinct advantage. In an actual airplane, it’s relatively easy to simulate breaking out of the clouds at MDA (or not breaking out) by using the hood/foggles/etc. But it’s virtually impossible to simulate breaking out and still not being able to really see anything. The only way to do that is to fly in actual IMC (I strongly advise this), or to use a simulator.

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