I am studying ICAO's PANS-OPS 8168 manual, and I am having trouble understanding the criteria applied to straight and turning missed approaches. In the manual, it clearly states:

I-4-6-2 Types of missed approach.

There are two types of missed approach:

a) straight missed approach (includes turns less than or equal to 15 degrees)

b) turning missed approach.

When there is a turn more than 15 degrees, it takes into considerations three cases (1. turn at altitude/height, 2. turn at at fix/facility, 3. turn at MAPt). As far as I can tell, each one of them concerns only a small initial portion of the whole missed approach. An example can be seen in the following picture.

enter image description here

Taking the above points into consideration, I would like to know if the requirement for turns less than 15 degrees does not concern all the legs of a straight missed approach, only those which are between the MAPt and the (potential) Turning Point. In other words, it seems strange to have, for example, only one turn more than 15 degrees near the end of the missed approach, which can be many miles away from the MAPt, and suddenly the whole missed approach to be considered a turning missed approach, instead of straight, with all the subsequent rules of a turning missed approach applied from the MAPt until the last waypoint.

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    $\begingroup$ Don't fixate on the 15° limit. In practice, some missed approach holding points are roughly straight (within a few degrees) all the way to the hold, and some are clearly not straight ahead, e.g. behind you. The former is obviously preferred when feasible. $\endgroup$ – StephenS Jul 9 '19 at 1:06
  • $\begingroup$ @StephenS thank you for your input. I am asking because there are different rules imposed, depending on the type of the missed approach (straight or turning), so in my opinion it is important that this distinction be clarified. $\endgroup$ – Vector Zita Jul 9 '19 at 3:36
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    $\begingroup$ In a "straight" missed approach, there will only be one "turn", which is just to align you (think wind correction angle) with a radial or such to go directly to the holding point. There won't be multiple legs like there often are for "turning" one. $\endgroup$ – StephenS Jul 9 '19 at 15:24

A straight missed approach can have a combination of both straight and turning parts. The straight part is called the intermediate missed approach, while the turning part is called the final missed approach. When a straight missed approach starts a turn of more than 15°, the turning missed approach criteria applies, as stated in Part I, Section 4, Chapter 6.3.4 of ICAO DOC 8168 Vol. II:

Wherever practical the missed approach track should be a continuation of the final approach track. Missed approaches involving turns are permitted (see 6.4, “Turning missed approach”), but should only be employed when an operational advantage may be obtained.

Take this approach from Ålesund Airport in Norway for example:

enter image description here

In the straight part you have a track change of 6°, which satisfies the criteria for a straight missed approach. This allows a reduced Minimum Obstacle Clearance (MOC) of 30 m, among other things. When AL821 is reached, the turning missed approach criteria is applied, and the MOC is increased to 50 m.

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