Missed Approach Point

[wince]

I have a doubt with regards to the MAP. Is it used exclusively as part of a non precision approach or can it also to be used in an ILS approach?

W

[galaxy flyer]

Missed approach point on an ILS is where the " on-course, on glide path" reach the DA, not earlier or later, assuming your are on course and path.

GF

[eckhard]

Hi Wince,

As gf and mig3 have said, the MAPt is not used on an ILS.

On a non-precision approach, the MAPt is the latest point at which a missed approach can be initiated at the MDA to ensure adequate obstacle clearance during the missed approach procedure.

On an ILS, the intersection of the DA(H) with the glideslope defines a point in space from which the initiation of the missed approach procedure will also ensure adequate obstacle clearance.

Some points to remember:

1. From the DA(H) on the glideslope (and localiser) of an ILS, a straight-in landing can be made on the runway touch-down zone using normal descent rates and manoeuvres.

2. From the MDA and MAPt of a non-precision approach, a straight-in landing may not be possible in the touch-down zone without using unusual descent rates or manoeuvres. This is why the concept of a VDP (Visual Descent Point) was introduced. It is also why, if you fly a constant-angle descent, (rather than 'dive and drive'), you should treat the MDA as a decision point and either land or go around when reaching the MDA. Adding 50ft or so to the MDA and calling this the 'DA' is a good idea.

3. If you decide to go around at or before the MDA, you may well not have reached the MAPt. As mig3 pointed out, you should climb ahead to the MAPt before initiating any turns. This will ensure that obstacle clearance is maintained during the missed approach procedure.

Hope this helps,

Eck

[reynoldsno1]

I believe it is possible to have a MAPt for an ILS, especially if the missed approach segment is restrictive - ISTR that the ILS at Fujairah has one?

[aterpster]

reynoldsno1:

I believe it is possible to have a MAPt for an ILS, especially if the missed approach segment is restrictive - ISTR that the ILS at Fujairah has one?

I can't imagine why. But, I always learn something about how some ICAO states apply PANS-OPS.

Could you provide the ICAO identifier for Fujairah?

Added: I found it: OMFJ

[mustafagander]

Many ILS charts double as LOC charts and hence a MAP is charted but the fine print says that it applies to the LOC procedure.

[rennaps]

I agree that the MAPt shown on an ILS chart is for the GP INOP procedure.
I don't think that Fujairah is a good example.
Take the ILS X RWY 29 chart for Cat A & B aircraft.
If you are a Cat B aircraft and do the ILS you have a minimum of 600ft but if you turn the gp off you get down to 580ft :confused:

[wince]

Thank you for all your replies. Normally a MAP for an ILS is at DA but my doubt came when going around before DA. If a Missed App Proc. dictated an immediate turn, I though you could then to the MAP then turn.

From the jeppesen manual ATC page 230 para 6.1.4

"It is expected that the pilot will fly the missed approach procedure as published. If a missed approach is initiated before arriving at the missed approach point (MAPt), the pilot will normally proceed to the MAPt (or to the middle marker fix or specified DME distance for precision approach procedures) and then follow the missed approach procedure in order to remain within the protected area"

W

[aterpster]

wince:

"It is expected that the pilot will fly the missed approach procedure as published. If a missed approach is initiated before arriving at the missed approach point (MAPt), the pilot will normally proceed to the MAPt (or to the middle marker fix or specified DME distance for precision approach procedures) and then follow the missed approach procedure in order to remain within the protected area"

That is correct.

[reynoldsno1]

I can't imagine why. But, I always learn something about how some ICAO states apply PANS-OPS.

PANS-OPS contains specific guidance material relating to the early termination of the precision segment with a missed approach turn at a designated Turning Point - not a MAPt as as such, but effectively so.

If you are a Cat B aircraft and do the ILS you have a minimum of 600ft but if you turn the gp off you get down to 580ft

Strange yes, but also remeber 600ft = DA 580ft = MDA

[rennaps]

"600ft = DA 580ft = MDA"

I don't see how 600ft can equal a DA of 580Ft?
The OCA for the ILS CAT 1 is 600ft
While the OCA for the GP inop (LOC only) approach is 580ft
As far as I understand it the Decision Altitude must always be above the Obstacle Clearance Altitude. Or am I missing something?

[reynoldsno1]

I only have access to a 2001 OMFJ chart that gives a DA of 585ft for the ILD and an MDA of 600ft for the GP inop.

I don't see how 600ft can equal a DA of 580Ft?

I'm sorry if I confused you - there is no correlation between DA & MDA. If you consider the minimum DA & MDA to be the respective OCAs, the methodologies to derive the ILS OCA & the GP INOP OCA are entirely different.

The ILS OCA will include a height loss margin added to any obstacle that penetrates a set of assessment surfaces peculiar to ILS. The OCA is the minimum DA, or a minimum OCH of 200ft (Cat 1)

The GP INOP (LOC) procedure is a non-precision approach and has a minimum obstacle clearance requirement. The set of assessment surfaces are assessed differently from the ILS. The OCA is the minimum MDA, or a minimum OCH of 250ft.

[rennaps]

those minimums were from the latest AIP entry.
Strange minimums to say the least. However I agree keep the GP on :cool: