boscomantico wrote:
But isn’t the article’s subtitle bad already?
Well that’s open for discussion ;-) I would say….referencing Skybrary ….the missed approach point may vary
https://skybrary.aero/articles/missed-approach
Reasons for discontinuing an approach include the following:
Although one can start a missed approach at various points the actual MAP is marked on a plate and does not vary except if there is more than one approach on the same plate which does happen from time to time.
The SUSP/UNSUSP debate is a little mischievous by A_A, as all pressing it to UNSUs does is to load automatically the next series of way points that make up the missed approach procedure instead of having to insert them manually as a series of directs or loading a missed approach FPL.
The RNP procedure is always loaded as approach final & missed, irrespective of OBS, Hold, SUSP modes, just look at FPL page after pressing Direct IAF and you will see everything all the way to the hold 
The MAPT on RNP can be both flyover (FO) for the final & flyby (FB) for missed, same as IAF when used as both holding fix or initial segment, UNSUSP/OBS does more just making up the missed procedure, it halts the sequence when you are in “FO mode” or “hold mode” and release to be in “sequence” or support “FB mode”, and second keeps runway guidance until you land (one should keep flying instruments with LPV guidance down to touchdown threshold, I only decide to continue or not at DH), technically, in NCO you should never go missed at MAPT, you are likely to go missed on DA or DDA (3D APV or 2D flown CDFA), or go missed at 1000ft agl if you get 550m RVR, or missed from circling:
- You don’t want MAPT as flyover on missed from circling unless you really like to go back to it again
- You don’t want MAPT as flyover on final before circling unless you are landing on adjacent parallel runway
Take Lydd, say I am 5nm DME on final with 1/2 scale deflection about what you need to bust D141, how about going missed at 5DME?
- Disregard the box and right turn immediately, use my SkyDemon to navigate?
- Keep climbing then over MAPT and press UNSUSP when you get there?
- Right turn, scroll on FPL and press direct BEMLA?
- Press UNSUSP and turn to BEMLA?
- Turn to BEMLA and press UNSUSP?
- Ask Lydd for vectors (they don’t have radar)
- Climb on RWY to 3kft and fly to ROMTI (just like the takeoff)
Someone can argue all the above is just making dog breakfast out of a very trivial thing like going missed (after all some boxes don’t even have SUSP/OBS mode and besides one can fly the paper plate just fine on compass without even looking at the GPS/HSI), I am sure I won’t die doing any of 7 choices at Lydd, they all seems to work fine but surely there is only one that works better in Switzerland
I doubt anyone will can get failed by CAA for not pressing UNSUSP on missed like in FAA? well lot of private EASA IR pilots got their IR & PBN with RateOne at Glocs with RNP+NDB, untill recently everybody with an IR/PBN issued by CAA was taught to use ADF or Radar to fly NDB missed & hold after their RNP not what they have in GPS/HSI boxes…
Glocs,
Or Shoreham,
For those who have even a passing interest in PBN especially in the UK can I recommend CAP773 as interesting reading.
@Ibra going missed before the MAP as you suggest is not flying the missed approach, and could be extremely dangerous.
It is not a good idea to fly the GP down to the threshold as just like the PAPI it is usually set up for the wheels touching down on larger aircraft which will have a greater separation between the cockpit and the tyres.
going missed before the MAP as you suggest is not flying the missed approach
I meant on ILS or LPV you put full power at your DA not at the MAPt? remember it’s called “decision altitude” on vertical navigation, that is where you start going missed: VDPt will always sits before MAPt on 3D with glide or 2D with CDFA, if you do Dive-n-Dive on LOC until the MAPt it’s different but there are one or two pilots who still do that outside the US…
Laterally, you always have to overfly MAPt, your life hangs on that 
Shoreham & Glocs missed I posted are not flown RNVA1 with PBN, they are pilot interpreted raw data on ADF but one will strongly suggest they are flown on their overlay like any RNP, 100% with GPS and only switch on the ADF for ramp checks…
gallois wrote:
The SUSP/UNSUSP debate is a little mischievous by A_A, as all pressing it to UNSUs does is to load automatically the next series of way points that make up the missed approach procedure instead of having to insert them manually as a series of directs or loading a missed approach FPL.
That’s not how it works at all (not even on Peter’s old KLN94). The full series of waypoints for the missed approach are loaded at the same time as the approach. There is never any need to insert them manually or loading a missed approach FPL.
What happens is that on final approach waypoint sequencing is suspended so that when you pass the MAPt, the navigator will not automatically sequence to the next leg in the flight plan. That means that the navigator will still guide you along the extension of the final approach course. Pressing the unsuspend button (or equivalent) simply starts waypoint sequencing again, giving you course guidance for the missed approach.
I suggest you find out the answer to my previous question. The answer (and the reason for it) may surprise you.
If you go missed on an RPN approach, the waypoint sequencing will suspend. When should you unsuspend it if
This is nothing to do with PBN; it is GPS box specific procedural stuff.
@Peter that is exactly what I was trying, perhaps clumsily to describe.
As A_A says the missed approach procedure is normally loaded and activated as part of the IAP it belongs to. On the approach, and depending on the system it suspends the automatic sequencing of way points so that you can land. (the positioning of this suspension seems to differ with different systems) .
If you decide at DA/H that you do not have the visual references to land you want to go round but your way point sequencing has been suspended, a bit like using the OBS to do holds.
If you hit the SUS button to UNSUS before the MAP that is still your active leg which is why you should do it after the MAP as I am told (I have never actually tried this) that some systems will direct you back to the beginning of the active leg that of the point at which the SUS automatically went into SUS mode. There are other anomalies which can occur such as sending you round in circles at the MAP (again it it something I have been told or read rather than experienced.) So it seems to be system dependent.
If there is a turn immediately at the MAP AIUI you should still press UNSUS after the crossing of the MAP if it is a fly over.
Many missed approach procedures mean climbing to a certain altitude before the turn. This altitude of course takes longer on some aircraft than on others or if you are already at or near that altitude when you pass the MAP the way point sequencing on certain IAP procedures may cause you to turn earlier than would be called for and in fact you might (again something I have read about but not experienced)
As you say Peter there is much that is very little different from the way you have been flying for years and as you add or change your equipment you will adapt with it.
PBN could be a great concept but IMO in Europe its benefits are being held up, not by pilots or equipment manufacturers but by perhaps EuroControl which may see the possible diminution of its power. (Sorry off topic political)
Airborne_Again wrote:
If you go missed on an RPN approach, the waypoint sequencing will suspend. When should you unsuspend it ifThe missed approach starts with an immediate turn at the MAPt?
The missed approach starts with a turn at a particular altitude?
Neither of the above?
Perhaps you should write exam questions for EASA ;-) They love this stuff.
Seriously though, it’s avionics learning not PBN learning. An instructor or examiner might be interested in exactly when you unsuspend, but as with many things in aviation that’s a different issue to how one operates in the real world.
In the real world I am just going to fly the missed approach as shown on the plate, or more likely take radar vectors for whatever’s happening next, and box-fiddling is secondary. Apart from anything else I don’t find the CDI/HSI an intuitive or especially useful instrument for close-quarters maneuvering that requires significant turns – a moving map is more my thing. For a simple one like the EGBJ RNP Rwy27 previously mentioned, the much-maligned ADF needle is actually pretty useful – it’s big, obvious, already tuned and you don’t need to press any buttons or be sure it’s in the right mode. You just follow the climb instructions then keep that turn going until you’re pointing back at the beacon.
Graham wrote:
For a simple one like the EGBJ RNP Rwy27 previously mentioned, the much-maligned ADF needle is actually pretty useful – it’s big, obvious, already tuned and you don’t need to press any buttons or be sure it’s in the right mode. You just follow the climb instructions then keep that turn going until you’re pointing back at the beacon.
That is the key thing for simple one all my 8 answers above work
On tricky one, you need to know what you are doing, not necessarily PBN rated, even a fiddle on the Garmin simulator or XPlane will sort you out …
There was an SR22 that crashed in Zell am See (LOWZ), I am not sure how much understanding of PBN topic is required for that one nor if any of this was the issue? all I know something happened on the missed of from "an RNP cloud-break far away from it’s MAPT”, I am dead sure I can’t fly that one following on paper plate instructions (I have played with that one in simulator flying headings and the result was ugly)
