ILS approach/personal minima
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ILS approach/personal minima
Q.150 in Standards Doc 10 QB: 'Describe the procedure for flying an ILS approach and calculation of personal minima, either with or without glide path information'
Brain-f**t moment - by 'personal minima' can someone pls confirm that the question is most likely to be referring to the standard DH and RVR minima for the various CAT I, II and III approaches, including Localiser-only non-precision minima. Just wondered whether 'personal minima' had some other reference in this context, e.g. Individual minima based on aircraft type, pilot experience, IR or IR(R) etc.
Many thanks
HW
Brain-f**t moment - by 'personal minima' can someone pls confirm that the question is most likely to be referring to the standard DH and RVR minima for the various CAT I, II and III approaches, including Localiser-only non-precision minima. Just wondered whether 'personal minima' had some other reference in this context, e.g. Individual minima based on aircraft type, pilot experience, IR or IR(R) etc.
Many thanks
HW
Well, your question was dated 22 May, it is now 11 June, so I suppose no one is certain about the answer. Therefore, I'll offer one suggestion. Although the Q relates, of course, to civilian qualifications, we know that the military have different grades of IR ( W, G, MG, etc). If some small operators or individuals chose to add an allowance for inexperience in the same way, that might explain the reference to "personal minima". Never come across it, but theoretically possible.
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Thanks keithl. It's obviously baffled others as it did me and in the absence of any other steer, I'll interpret the question in terms of plain and simple 'minima' rather than 'personal minima'. I'm sure the FIE will put his own interpretation on the Q should it ever come up.
HW
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I guess you could explain how you got to your personal minima and how its derived i.e AOM, minimum system DH/MDH, OCA/H, plus your personal additive.
For example some NPA only require 1.2 RVR but I personally wouldnt attempt one less than 2km during single pilot, because i know from experience you will struggle to land from it.
For example some NPA only require 1.2 RVR but I personally wouldnt attempt one less than 2km during single pilot, because i know from experience you will struggle to land from it.
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Your personal minima are the minima you will apply to that particular approach, in that particular aircraft, at that particular time.
The starting point is always the system minima, which for an ILS Cat I is 200' height above the touchdown area.
Is the OCH higher than system minima?
Then the OCH is the minimum possible decision height.
Are you out of practice?
If so the CAA recommend adding another 100' to the DH (good advice for real life, but probably not acceptable for a Test)
Are the conditions gusty or turbulent?
If so the CAA also recommend adding another 100'. Even if they overrule you, on a Test, an Examiner should praise you for having taken that into account.
Are you in a twin, doing a single engine approach?
Due to poor Go Around performance, below 300' you are pretty much committed to land so, in this case, your absolute minimum DH on an ILS would be 300'.
Do you hold an IR or an IMCR/IR(R)?
Although, legally, you may fly to system minima with an IMCR/IR(R) an Examiner would expect you to have added in the recommended extra 100' and, in any case, not to have a DH lower than the recommended absolute minimum of 500' for IMCR/IR(R) holders.
Are you going to fly the ILS with the QNH (usual), or the QFE, set?
You must be able to convert your personal calculated DH to a personal DA.
There is a lot to consider when calculating personal minima
The starting point is always the system minima, which for an ILS Cat I is 200' height above the touchdown area.
Is the OCH higher than system minima?
Then the OCH is the minimum possible decision height.
Are you out of practice?
If so the CAA recommend adding another 100' to the DH (good advice for real life, but probably not acceptable for a Test)
Are the conditions gusty or turbulent?
If so the CAA also recommend adding another 100'. Even if they overrule you, on a Test, an Examiner should praise you for having taken that into account.
Are you in a twin, doing a single engine approach?
Due to poor Go Around performance, below 300' you are pretty much committed to land so, in this case, your absolute minimum DH on an ILS would be 300'.
Do you hold an IR or an IMCR/IR(R)?
Although, legally, you may fly to system minima with an IMCR/IR(R) an Examiner would expect you to have added in the recommended extra 100' and, in any case, not to have a DH lower than the recommended absolute minimum of 500' for IMCR/IR(R) holders.
Are you going to fly the ILS with the QNH (usual), or the QFE, set?
You must be able to convert your personal calculated DH to a personal DA.
There is a lot to consider when calculating personal minima
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My opinion:
Adding to minima to account for personal circumstances appears to offer benefits. However...
One airline I worked with prescribed additions to minima for newly-qualified captains. Thus it was one day that while the rest of the fleet got where it was going, one brand-new left-seater, who had spent the previous seven years of his career flying to 200 ft aal on the same ILS approach using the same procedures in the same type of aircraft at the same destination, found himself going around and diverting to his alternate, where the weather was, similarly, legal, but unpleasant. A small delay saw him landing, quite legitimately, with little fuel remaining in his tanks, at an aerodrome he didn't know, with passengers who didn't want to be there. (Lack of familiarity with the destination is a huge factor in commercial transport hull losses).
The degree of risk involved in a go-around and diversion will almost certainly always be greater than the degree of risk in a trained and tested pilot flying the final 100 ft or so of an instrument approach which has been designed and equipped to be flown to that limit, and then landing where he wanted to go.
By all means apply higher planning minima, and decide not to go, but it seems to me that applying greater operating minima has nothing to do with proper management of operational risk. (If the approach then gets out of shape, of course, go around as you would at any stage of any approach).
Similarly, I don't agree with the use of ACH as DH in piston twins. The exposure to risk for the part of the approach below ACH but above the appropriate DH is tiny in comparison with other risk encountered in twin piston operations. If an engine failure occurs, you simply have to accept that you will land off the approach regardless of when you get visual references.
(I'm not suggesting by the way that IR(R) holders should fly to IR limits).
Adding to minima to account for personal circumstances appears to offer benefits. However...
One airline I worked with prescribed additions to minima for newly-qualified captains. Thus it was one day that while the rest of the fleet got where it was going, one brand-new left-seater, who had spent the previous seven years of his career flying to 200 ft aal on the same ILS approach using the same procedures in the same type of aircraft at the same destination, found himself going around and diverting to his alternate, where the weather was, similarly, legal, but unpleasant. A small delay saw him landing, quite legitimately, with little fuel remaining in his tanks, at an aerodrome he didn't know, with passengers who didn't want to be there. (Lack of familiarity with the destination is a huge factor in commercial transport hull losses).
The degree of risk involved in a go-around and diversion will almost certainly always be greater than the degree of risk in a trained and tested pilot flying the final 100 ft or so of an instrument approach which has been designed and equipped to be flown to that limit, and then landing where he wanted to go.
By all means apply higher planning minima, and decide not to go, but it seems to me that applying greater operating minima has nothing to do with proper management of operational risk. (If the approach then gets out of shape, of course, go around as you would at any stage of any approach).
Similarly, I don't agree with the use of ACH as DH in piston twins. The exposure to risk for the part of the approach below ACH but above the appropriate DH is tiny in comparison with other risk encountered in twin piston operations. If an engine failure occurs, you simply have to accept that you will land off the approach regardless of when you get visual references.
(I'm not suggesting by the way that IR(R) holders should fly to IR limits).
