[jhb_airlines] Re: Standard Procedure

  • From: "Bones" <bones@xxxxxxx>
  • To: <jhb_airlines@xxxxxxxxxxxxx>
  • Date: Fri, 21 Oct 2005 06:00:38 +0100

-----Original Message-----
From: jhb_airlines-bounce@xxxxxxxxxxxxx
[mailto:jhb_airlines-bounce@xxxxxxxxxxxxx] On Behalf Of Gerry Winskill
Sent: 20 October 2005 20:09
To: jhb_airlines@xxxxxxxxxxxxx
Subject: [jhb_airlines] Re: Standard Procedure

I'd noted the two different, Cat related, JSY departure courses. Which
brings us to the next one; is the CAT aircraft type specific, company
set, or what? The most common a/c flown by JHB, in the FPI sessions,
seem to be B737, A32*, F100. Are there specific CAT applying to each or
would it be a common one for the group covered?

Gerry Winskill

I'll have to go to HTML for this email. Sorry for this but it will be easier
to read..

How deeply do I dive in here?

In the past I have had quite a few innocent questions that have opened up
huge chasms <g> but this one is a bit trickier.

I could answer it in a few lines but then I see the thin ice that it is
leading towards - something I have been avoiding for a few years. I suppose
it is inevitable but FS is getting so good that it is requiring more and
more understanding of real world procedures and FPI amplifies this. I don't
think we can avoid the thin ice much longer.

Topics I have covered in the past have been interesting to you (I hope) but
I think we are now reaching a point where we are going to have to go
further. I say I have been reluctant to delve into this area and this is
because FS is supposed to be fun. My tutorials have mostly been on subjects
like navigation or aircraft performance - meaty stuff that is a good and
enjoyable read. Going onward is pressing us more and more against the
doorway marked Rules and Regulations and I really do hesitate in pushing you
through it.

The trouble is that all real pilots have to do a lot of ground school as
part of their training.
The trouble with FS (and FPI) is that you aren't PPL's because you all fly
around in big tin - you are ATPL standard. 
The trouble is that all the groundwork is missing...
The trouble is that I've avoided this groundwork as it is not exciting,
meaty stuff. It's tougher stuff, not the least because some of it is dull.

I guess that we could possibly take it in stages and that we build up
knowledge slowly.

Back to aircraft Categories. I'll just include a snippet from the docs to
show you what that thin ice is covering..

1 Holding and Approach to Land Procedures
1.1 General

1.1.1 UK Holding and Instrument Approach Procedures are designed using
criteria contained in ICAO Document 8168-OPS/611
(PANS-OPS) VOL II. These criteria include:

(a) The use of Obstacle Clearance Height (OCH) as the basic obstacle
clearance element in calculating minima;
(b) aeroplane categories related to speed, which can result in a reduction
of Obstacle Clearance Heights for the more
manoeuvrable aeroplanes;
(c) the definition of a Missed Approach Point for non-precision procedures;
(d) the use of the term 'Decision Height' in relation to precision
procedures and 'Minimum Descent Height' in relation to nonprecision
and Visual (Circling) procedures.

1.1.2 The UK Holding and Instrument Approach Procedures appear at AD 2.24.

1.1.3 PANS-OPS stresses the need for flight crew and operational personnel
to adhere strictly to the published procedures in
order to achieve and maintain an acceptable level of safety in operations.
In addition, within the UK, procedures contained within
Controlled Airspace are subject to Rule 31(3)(a) of the Rules of the Air
Regulations 1996 (IFR within Controlled Airspace).

Jump here to skip two sections on Visual Manoeuvring and VDF letdowns.

3.10 Aircraft Categorization

Aircraft Category A - nominal Vat less than 91 kt IAS
Aircraft Category B - nominal Vat 91 kt to 120 kt IAS
Aircraft Category C - nominal Vat 121 kt to 140 kt IAS
Aircraft Category D - nominal Vat 141 kt to 165 kt IAS
Aircraft Category E - nominal Vat 166 kt to 210 kt IAS
Note: Nominal Vat is defined as 1.3 x the stalling speed in the landing
configuration at maximum certificated landing mass.

I've skipped the rest but you can look it up in the AIP at ENR 1.5.1.

Aircraft categorisation allows the planners of IAP's to draw up appropriate
procedures for aircraft of varying speeds. The categorisation is not only
essential for the basic IAP itself but for associated procedures like
holding patterns, missed approach and circling minima. Each of these will be
drawn up with regard to the aircraft's speed, it's turning radius and its
probable climb and descent gradients. The rest of the ENR pages are full of
diagrams and tables that amplify the text.

As for the aircraft you mention most are likely to be in Cat C. Note that
the nominal Vat is defined as being at maximum certified landing mass i.e.
MLW so the real weight of the aircraft is not of consequence. The F100 might
just creep into Cat B as it was designed for short field capabilities and
its big flaps might push down the stall speed into the Cat B area - that is
just a guess though.

If we start getting into these deeper waters again I won't refrain from
answering the questions. They may get a bit complex though - it depends
whether the answer involves other unknown subjects!

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