Re Peeka4y's response:
Quote:
Remember that while the LOC MDA is a "hard deck", the ILS has to provide protection even if the aircraft is flown below the glide slope (up to full deflection), and below the DA when a missed approach is initiated.
It's still rather strange that the ILS Cat I DAs for Cat BCD are higher than the LOC Only MDA!
Perhaps if they lopped off the top of some of those trees in the final segment (as shown in the "Southern Germany" lookalike pic) the CRM analysis for determining the minima for the precision approach? Or, perhaps those who designed the approaches only used the OAS (Obstacle Assessment Surfaces) method and didn't do a CRM (Collision Risk Method) analysis, where the latter may in fact give lower DAs that are equally safe.
Re EnxAero's response to Defred:
Quote:
I guess what peekay4 means is that if you started the missed approach at precisely DA, the aircraft still loses a bit of altitude until you it starts to climb, and it goes slightly below DA. Those few ft are taken into account and the aircraft is protected.
Design of Approaches using Vertical Guidance, where the minima is expressed as a DA/DH (and even RA), always takes into account the sink rate factor that's going to occur if the Decision is made to GA
AT or ABV the DA/DH (MA
not initiated after/BLW).
And so as EnxAero indicated in one reply, in such cases the design provides protection in the missed approach (for normal ops ... ie, not necessarily EO conditions).
Re the Cat II APCH and the relatively unusual large RAs due to the valley in the 1k are prior to the THR - yup, it is a bit special! Especially if the RA at around 1.6NM (3k) is less than the RA at the 0.5NM (1k) mark!
Possibly that's why that Cat II APCH is a special authorisation required (ref chart below) procedure?
Hmmm, interesting diversion.