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Driver170

RNAV, MAP

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Hi i'm looking at Navigraph charts. EGKK RWY 08R RNAV

 

I'm confused about the MAP and the MDA. It says for acft that are CAT C the MDA is 700 AGL. In the little box it says MAPt RW 08R? Now i'm confused with these two can someone highlight the differences.

 

Also on the chart it mentions, MISAP later of 2000 1nm THR. What does this mean?

 

Can someone explain all these differences to me. Thanks!

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I don't navigraph charts, but I guess MAP RW08R is an approximate missed approach point.

 

And missed approach procedure can be performed above 2000' in 1nm after runway threshold.

 

Anyway charts are needed to clarify this.

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It's simple, you are allowed to descend to MDA/OCA (in this case 700ft AMSL, not AGL) and fly that altitude to MAPt. Of course, it's not particularly smart to fly in this way in airliner, so you follow RNAV profile. MISAP is procedure for missed approach: Straight ahead until passing 2000or 1NM inboundRW08R whichever is later, turn right heading 179° then as directed by ATC.

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But wouldn't the MAP be at the MDA? Just all confusing.

Lj that reply wasn't for you

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Now i'm confused with these two can someone highlight the differences.

 

MDA is minimum descent altitude - the lowest you can descend.  It is a vertical limit.

MAP (occasionally written "MAPt") is the missed approach point - the farthest you can travel forward until you must go missed.  It's a lateral limit.

 

The MAP is used in conjunction with an vertical (altitude) limit, because if you only had a vertical limit, you could remain at that altitude indefinitely.  In an area of high terrain, this would be very bad.  So, you'll have an altitude limit (MDA/DH/DA/etc), and also a MAP on all approaches.  On some approaches, the MAP may not be specifically depicted on the chart (usually with an 'M') and is implied in hitting DH or DA (this is why they're called decision height/altitude instead of MDA/MDH).

 

 

 


Also on the chart it mentions, MISAP later of 2000 1nm THR. What does this mean?

 

The ICAO chart that I have for it makes it a little more clear.  Basically, it's saying "initiate the missed approach procedure at the latter of either reaching 2000 or being within 1nm of the runway threshold."  In other words, if you're passing 2000 (on the way to 3000) before getting to the MAP, don't make any turns until also getting within 1nm of the MAP; or, if you get to the MAP and haven't passed 2000 (on the way to 3000), wait until passing 2000 before making any turns.

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Right i see now, thanks for that. So you descend to MDA 700 AMSL at that point your at 1.5nm from the RWY is that right? Then you can continue 700 but that would be crazy, 700 feet above the runway and then you try to land?

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Yea, you would require about 6 degrees glide to achieve that, but, that's just in case you see the runway just at the minimums. When you see the rwy, you are allowed to proceed visual bellow MDA.

 

@voske: good, I'm referring to that chart but forgot to post it here! I highly recommend eurocontrol charts for flying in Europe over any other source, as it's free, it's up-to-date, and it's official.

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On some approaches, the MAP may not be specifically depicted on the chart (usually with an 'M')

 

In this case the MAP is depicted on the chart at the runway threshold.

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Why would you continue at MDA if you can't see the runway? It shows to MAPt on that chart in the UK? Why would you continue at 700 and wait till your over the runway?

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You can start to climb earlier, but they want to prevent early turns. Note 5 on the chart is:

 

 

An early initiation of the missed approach may require pilot intervention with the RNAV system in order to comply with the 1NM inbound turn initiation point.

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Why would you continue at MDA if you can't see the runway? It shows to MAPt on that chart in the UK? Why would you continue at 700 and wait till your over the runway?

Some aircraft can do it, for example Cessna 172 would land from MAPt with ease. You do not have to fly all the way to MAPt if you feel it's out of parameters for your aircraft to land. That's why missed approach have that "fly straight ahead to 2000ft or 1nm inbound, whichever is later."

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In this case the MAP is depicted on the chart at the runway threshold.

 

Yes.  I only added that to be complete in my answer.  Note how I specified what the MAP symbol looks like when included on charts (which would be the case here...)

 

 

 

 

 


Then you can continue 700 but that would be crazy, 700 feet above the runway and then you try to land?

 

...one of the many simisms out there.

 

Once you have a visual on the runway, you're flying a visual approach.  So, if you spot the runway at 700 right over the threshold, and you determine that you can keep it in sight during whatever maneuver you need to make to get back into position for a normal approach, then you can do so.  In fact, there are thousands of approaches worldwide in which the approach will dump you off at a very awkward angle to the runway such that you can't make a straight in approach, and are occasionally still at 1000' right over the runway.

 

As I say in one of my videos, approaches are simply instructions on how to get to the airport environment.  If it allows a straight in approach, just thank the chart designer for making it easier for you.

 

 

 


Why would you continue at MDA if you can't see the runway? It shows to MAPt on that chart in the UK? Why would you continue at 700 and wait till your over the runway?

 

Why not?  Going missed means you're flying the whole procedure all over again.  That's a lot of time and fuel.  If you spot the runway at 700 and right over the threshold and determine that you can keep it in sight and make a safe approach from that point, then you should be able to do so.

 

As I always say:

Aviation is not as strict and formulaic as many simmers assume.  There's a TON of discretion allowed to crews.  This is one of those cases.

 

Here's one for you:

All of the approaches to JYO are for Runway 17.  Wind favors 35.  I hit the MDA, but don't have the runway in sight before the threshold.  Should I initiate the missed right as soon as I hit the MDA, or, since I can wait until the threshold, should I wait until then?

 

Since the circling mins are the same as the MDAs on the approaches there, I can fly at the MDA/circling mins as I break off of the approach path and enter into a "traffic pattern" to land on Runway 35, provided I can keep the runway environment in sight during that maneuver.

 

As I mentioned in my last section:

Never forget that approaches are instructions to get you to the airport environment in general.  They may reference a specific runway, but unless they say "circling approaches prohibited" (or circling mins are not published at the bottom), you can use that approach to land on any runway you so choose (provided this is coordinated with the controllers, if the field is controlled).

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Here's one for you:
All of the approaches to JYO are for Runway 17.  Wind favors 35.  I hit the MDA, but don't have the runway in sight before the threshold.  Should I initiate the missed right as soon as I hit the MDA, or, since I can wait until the threshold, should I wait until then?
 
Since the circling mins are the same as the MDAs on the approaches there, I can fly at the MDA/circling mins as I break off of the approach path and enter into a "traffic pattern" to land on Runway 35, provided I can keep the runway environment in sight during that maneuver.
 
As I mentioned in my last section:
Never forget that approaches are instructions to get you to the airport environment in general.  They may reference a specific runway, but unless they say "circling approaches prohibited" (or circling mins are not published at the bottom), you can use that approach to land on any runway you so choose (provided this is coordinated with the controllers, if the field is controlled).

 

Generally, I agree, but if there are few aircraft behind you tightly separated for maximum runway efficiency, there's no way you can do anything but go around. 

 

Great example is MHTG Toncontin Intl, where if you do not have radius to fix feature (PMDG), you have to fly that crazy VOR approach leaving you at really inconvenient place to proceed visually. Even then, company would not allow you to fly whatever you want; they would give you visual procedure- what landmarks to follow.

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