Marsen wrote:
My main question is how you determine that a runway is a CAT I PA runway or not – there does not seem to be anything in the AIP that indicates this. Yet the regulations refer to it as a decision point in the calculation of minima…
I’d say that the document refers to it as one of the acceptable means of compliance with the regulation. :)
Well, how would you know that the runway minima has been raised? AIP and/or NOTAMs. That is the only way. If there is nothing there, then all good.
Same as if they’ve changed/broke the lighting and/or added some temp obstacles etc.
@Airborne_Again, can you think of any sources of that information (other than contacting aerodrome ATS)?
When I was studying two years ago for the IR exam I figured out how to obtain the minimums without using Jepp charts. I don’t remember all details, but in principle you include runway lighting, runway/approach type and OCA, that’s it. I included this in my flight preparation app (well, excel sheet that I made to look like an App) that I run on my iPad. Most of the times the minimums that I calculated match the numbers on the Jepp chart. And then there comes an approach where it doesn’t match and you have to go into details. Sometimes I think Jepp is wrong. But we’re talking about several tens of feet. I finally stopped doing that.
To understand which type of runway lighting leads to which possible minimum wasn’t really straightforward for me.
@arj1 the information needed for the calculation is all in the “official” approach chart.
I don’t remember all details, but in principle you include runway lighting, runway/approach type and OCA, that’s it.
Certainly it’s not quantum physics 
UdoR wrote:
@arj1 the information needed for the calculation is all in the “official” approach chart.
That’s exactly the thing I am questioning here, I do not see all the necessary information on the “official” approach chart to follow the prescribed AMC (sorry for being pernickety). Specifically, there is no indication as to whether the runway is a PA or NPA – I can’t seem to find this in the AIP either. This is needed for the AMC procedure above. And if you are flying a complex aircraft it’s explicitly part of the AMC procedure (step 4) below so the information must exist somewhere surely?
Emir wrote:
I don’t remember all details, but in principle you include runway lighting, runway/approach type and OCA, that’s it.Certainly it’s not quantum physics
@Emir, yes, I know, BUT… (and they it’s a very big but) :)
That extra addition changes things somewhat. I understand it for a non-instrument runway (in EASA world that is for approaches without AIP), but PA/NPA is an interesting one – how would you know (beyond the basic things like a paint job)?
Does runway lighting, approach lighting, runway markings affect the DA or MDA?
It was my understanding that these factors only affect the RVR minima for take off and landing.
A precision approach would normally be using an ILS or LVP or rarely a PAR or MLS and the approach DA would be 200ft above OCH.
An NPA would depend on the type of final approach “instrumentation” a
being used and then you add the figure as on the table above to the OCH.
arj1 wrote:
I’d say that the document refers to it as one of the acceptable means of compliance with the regulation. :)
Yes and no. Unless there are alternate means of compliance (AltMOCs), then it is the acceptable means of compliance. Of course, with part-NCO you can devise your own AltMOCs without having them approved.
But I have a problem with this AMC. AMCs are supposed to explain how to comply with the actual rule which is often goal-oriented rather than specific. E.g. there could be some general statement that the pilot should “consider” obstacle clearance surfaces or runway classification when deciding on minima and then the AMC would provide an acceptable way of doing so. But in NCO.OP.111 there is no such requirement at all, so in my mind the AMC should really have been a GM.
@Airborne_Again, can you think of any sources of that information (other than contacting aerodrome ATS)?
The only thing I can think of is the Aerodrome Obstacle Chart (AOC) which should be published in the AIP for every instrument runway. The lack of an AOC for a runway could possibly be interpreted to mean that the runway is not an instrument runway. Also I suppose you could use it to determine if the runway has PA or NPA obstacle surfaces, but I’d need to check in PANS-OPS to be certain.
Who would one contact at the authority in order to get clarification on this?
Marsen wrote:
I can’t figure out when this would have any impact as surely you’ve already factored this in by taking into account the System Minima. What am I missing?
A clue comes from the last line in Table 8 that you quoted. It refers to NC*C*.OP.112. That is obviously a mistake, and is a copy-paste error, which suggests that AMC1 NCO.OP.111 was copied in from Part-NCC at a late stage of the process by a well intentioned editor who wasn’t part of the drafting group. And AMC1 NCO.OP.111 is not mentioned in the Explanatory Note, which describes the rationale for all the other stuff.
And if I were to hazard a guess, I’d say that the difficulty for the pilot to determine the runway category, together with the higher acceptable level of risk in NCO, might have been in the mind of the drafting group when they intentionally omitted the runway category from the calculation of DH/MDH.
Let me see what I can find out…
