Trying to comprehend CASEII/III coms

[sirrah]

Two questions:

 

1)

After calling inbound for a CASEII/III approach, Marchal will responds and, among other info, calls out [MARCHAL RADIAL BEARING]. What exactly does this mean and what do I need to do with this info?

It's described on page 40 of the SC user manual, but I didn't find a proper explanation of what it actually means and what I need to do.

 

 

2)

Did I understand correctly, that the DME distance and angels that are responded after the inbound call, refer to the location of the Marchal holding stack? So 23 DME, Angels 8, actually means, the Holding stack is 23nm/8000ft behind the carriers BRC? (so exactly inline with the BRC?)

[t1mb0b]

I think it's a case of yes to both your questions.

 

 

As i understand the modelling that is used at present the bearing given is the reciprocal of the BRC, you will hold on the bearing FROM the carrier, turning outbound no closer than the range(DME) and the Angels given.

 

 

Your heading to the carrier (hopefully timed so that you are on the inbound leg) will be the BRC.

 

 

In real life I beleive the hold for a case III is normally offset from the BRC, maybe this modelling or option will come later to DCS.

 

 

I'm sure someone will literally shoot me down in flames if I am out of line above :thumbup:

[Northstar98]

Two questions:

 

1)

After calling inbound for a CASEII/III approach, Marchal will responds and, among other info, calls out [MARCHAL RADIAL BEARING]. What exactly does this mean and what do I need to do with this info?

It's described on page 40 of the SC user manual, but I didn't find a proper explanation of what it actually means and what I need to do.

 

2)

Did I understand correctly, that the DME distance and angels that are responded after the inbound call, refer to the location of the Marchal holding stack? So 23 DME, Angels 8, actually means, the Holding stack is 23nm/8000ft behind the carriers BRC? (so exactly inline with the BRC?)

 

You've basically got it. But instead of being inline with the BRC, the direction of your approach stack, from the carrier, is what the radial means. The holding stack is a geometric stadium, with 2-minute turns and 1 minute legs (the leg away from the boat should correspond to the Marshal's radial, and the other the reciprocal).

 

At the moment, in DCS Marshal always puts the holding stack behind the carrier, so the [MARSHAL RADIAL BEARING] will be the reciprocal of BRC.

 

So for instance: “[sIDE NUMBER], [sHIP CALLSIGN] marshal, CASE II/III recovery, CV-1 approach, expected BRC [CARRIER HEADING], altimeter [PRESSURE]. [sIDE NUMBER], marshal mother’s [MARSHAL RADIAL BEARING] radial, [DISTANCE] DME, angels [ALTITUDE]. Expected approach time is [TIME]”

 

From the carrier, your approach stack should be on a bearing of [MARSHAL RADIAL BEARING] from the carrier, at a distance of [DISTANCE] away, at [ALTITUDE].

 

 

The time at which you begin your approach is given as a 2 digit number. It means the minute of the current (or next(?)) hour AFAIK. So if the current time is say, 20:00, and Marshal says "expected approach time 23" this would correspond to 20:23.

 

If the current time is 20:55 and Marshal says "expected approach time 10" that would correspond to 21:10

 

Hope that helps!

Edited June 28, 2020 by Northstar98

[felixx75]

Two questions:

 

1)

After calling inbound for a CASEII/III approach, Marchal will responds and, among other info, calls out [MARCHAL RADIAL BEARING]. What exactly does this mean and what do I need to do with this info?

It's described on page 40 of the SC user manual, but I didn't find a proper explanation of what it actually means and what I need to do.

 

 

2)

Did I understand correctly, that the DME distance and angels that are responded after the inbound call, refer to the location of the Marchal holding stack? So 23 DME, Angels 8, actually means, the Holding stack is 23nm/8000ft behind the carriers BRC? (so exactly inline with the BRC?)

 

 

[sirrah]

Ah, how stupid I didn't notice before that the radial is exactly 180 degrees from the BRC :doh:

 

That explains it indeed. Thanks guys

[Pieterras]

All answers are in here ;)

 

https://forums.eagle.ru/attachment.php?attachmentid=241826&d=1593968798

[Bunny Clark]

Ah, how stupid I didn't notice before that the radial is exactly 180 degrees from the BRC :doh:

 

IRL it won't always be, and in future Super Carrier builds it may not always be, so I would not get too used to that always being the case.

 

When given the position of the marshal stack I'll always enter into the CSEL right away. Once given BRC on your approach you can change the CSEL or just verify that it's the reciprocal of the marshal radial with a quick glance at the HSI. Right now, it typically doesn't matter as I can usually pickup ICLS in the marshal stack and confirm that I roll out on the correct heading without even needing TACAN. But it's good to be aware that after a future update this might not be as simple.

[tweet]

An awesome old technique for doing reciprocals is the +2/-2 or -2/+2 method. This refers to using simple addition and subtraction on the first two digits of the radial to get a course TO the station or a course TO the station to radial/bearing. The marshal stack is given as a radial but to use it you need the course to the boat. This method is simple and fast. Lets try some examples.

 

Flying radial 360 TO the carrier is what course? Since the first digit is 3 the -2/+2 is probably easiest: 3-2=1 and 6+2=8 The final digit is whatever was given. The result is 1,8, 0 or 180, due south.

 

090 is best solved with +2/-2: 0+2=2 and 9-2=7 => 270

 

Try some on your own. You'll find some aren't clear which easier like 110. Simply adding 180 is easy so try that first: 110+180=290. If you don't happen to think about adding or subtracting 180 or get confused the method still works but you'll need to think a little. 110 is easiest is you do +2/-2: 1+2=3 but 1-2 gets confusing. Put the 3 (we're really taking 20 from 300) in front for 31-2=29 => 290.

 

It takes a little practice but after awhile doing reciprocals is like breathing.

 

There's a nice little shortcut for adding minutes and seconds times too. I'd give it to you but I don't want to cause any helmet fires.

Edited July 20, 2020 by tweet

[Stearmandriver]

Or, add 200, then subtract 20 (or vice versa).

[Nazgûl]

 

I’m going to leave my apologies for two things in the video: the first is that I dim the panel lights a lot. Perhaps this makes visualization a little difficult. Second is that I didn't notice the Holding Stack at the time that ATC tells me to do it. But despite all that, I think this video can help in some way :)