[jhb_airlines] Re: Another one for Bones...

  • From: "Bones" <bones@xxxxxxx>
  • To: <jhb_airlines@xxxxxxxxxxxxx>
  • Date: Thu, 24 Nov 2005 19:52:12 -0000

No - it doesn't give the nominal speed for the printed procedures on the
plate itself. You will find this somewhere in the introductory pages in the
AIP.

The printed charts are all based on a nominal speed as turn rates vary with
this. The holding patterns are based on (I think) 140kts and the arcs on
(again I think) at 130kts. You are right that at slower speeds a less than
Rate 1 turn would be required - or that you turn at Rate 1 knowing that it
will bring you short of the FAT. Of course any wind will compound the
calculations but its better knowing in advance that a procedure will have a
certain effect rather than finding out the hard way.

You are right about the hold. A pilot flying directly to the NDB could go
straight into the teardrop procedure but once in the hold the extended
downwind leg is the only option. Again this is tricky because if you have
the drift nailed down then, instead of applying 3x drift angle on the
downwind leg, you have to apply the 1x drift as used on the inbound leg. In
reality, by the time you have gone downwind to 8DME your actual position can
vary a lot. If the turn back to the centreline brings you over the IF fix at
8 DME then you will have done very well indeed.

bones

-----Original Message-----
From: jhb_airlines-bounce@xxxxxxxxxxxxx
[mailto:jhb_airlines-bounce@xxxxxxxxxxxxx] On Behalf Of Peter Dodds
Sent: 24 November 2005 17:57
To: jhb_airlines@xxxxxxxxxxxxx
Cc: pdodds@xxxxxxxxxxxx
Subject: [jhb_airlines] Re: Another one for Bones...


John,
Many thanks for that excellent analysis.  Nice to know that it's
a hard one to fly. I did manage it last night once I realised
that the final turn started when the RMI indicated 108 degrees.
However, I hadn't appreciated that the turn radius assumes 130
knots (does it say that anywahere on the plate?) I was doing 120
at that point so the rate 1 turn radius would be a fraction
tighter (I've got a formula on a spreadsheet somewhere) so I
could probably have reduced the bank angle to around 15 degrees,
but the autopilot doesn't do that, so it would be better to delay
the turn another degree perhaps 2.

Nor had I appreciated that the final approach track was offset
from the runway centreline (I didn't read the small print!) and
assumed that 094 was the runway centreline bearing.

One further point - If you enter the hold, then I assume that the
transition into the approach is to follow the extended hold path
out to 8DME then turn inbound? The teardrop would only be flown
by those pilots not being required to enter the hold. Would I be
correct?

Incidentally, if anyone on the list wants to practice NDB or SRA
approaches, Gloucestershire is open every Tuesday evening on
VATSIM. The controller is Mike Pike and he is very helpful and
experienced and gets quite a few people practising instrument
approaches. He isn't there next week, but will be the week after.


Peter



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