[jhb_airlines] Re: Autopilot APPR HOLD problem

  • From: Mike Lucas <mhlucas@xxxxxxxxxxxx>
  • To: jhb_airlines@xxxxxxxxxxxxx
  • Date: Sat, 15 Oct 2005 12:48:12 +0100

bones

Thanks for this info, and your other reply on gauge design. I have no desire to enter a minefield ....

I may try a different panel with the Citation and see if I can get APPR_HOLD to work.

Think I've got the AP autothrottle and IAS hold sussed now ... <g>

Mike L

Bones wrote:
You are walking into a minefield here Mike so it may be best to leave well
alone. I don't know anything about the panel you got for the C550 but it
would need a much closer look at the gauges supplied to see what was
included in the package and what was not.

The gauge line you quote doesn't mean a lot to me as I don't have a
fsd_generic.ap.appr.gau (it could be a CAB file too). It becomes tricky
because just because the line is in the panel.cfg file it doesn't
automatically mean the gauge itself is in your gauges folder. Although
likely I can't even say this is an APPR hold function either. It's unusual
if it is because ALL the autopilot functions are normally contained in a
single autopilot gauge.

The FS command AP_IAS_HOLD is a different beast to AP_AUTOTHROTTLE. If you
set a P8 button for the latter then (assuming the aircraft is fitted with an
AP and AT in the aircraft.cfg file) you have access to speed control - it
is, effectively, the Autothrottle Arm function.

The AP_IAS_HOLD function is the same as the IAS button on the autopilot
panel on most aircraft. This is an engage/disengage button but it has no
effect if the Autothrottle isn't armed in the first place. You don't need to
allocate this button to a P8 switch because it should already be programmed
into the HOLD button below the IAS/Mach rotary switch on your MCP. It's the
same as the NAV and HDG hold buttons alongside - press to engage or
disengage.

So, what you should really have is the AP_IAS_HOLD command set to the HOLD
button below the IAS/Mach panel on the MCP. On the P8 you allocate a button
for the AP_AUTOTHROTTLE function. When flying the aircraft you hit the P8 to
arm the autothrottle, dial in a speed you want and then press the HOLD
button to engage.

You can mostly ignore the reference speeds in the aircraft.cfg as they are
only used in one of the FS menus - I think Weight and Balance. They have
absolutely no effect on the sim itself. The speeds are actually the wrong
way round but they are correct - the Citation has a very low stall speed. It
was intentionally designed for slow flight as it gave the aircraft the
ability to operate out of very short strips - something no other jet is
capable of. It was an impressive feat by Cessna as the aircraft doesn't have
any complex wing devices at all, but there again it is quite a light
aircraft.

What is good about the Citation is that at 100kts the aircraft still has
excellent roll rate. It is a very nice aircraft indeed for a pilot and
doesn't really deserve its "toy jet" title from the Lear/Falcon brigade.

bones


-----Original Message----- From: jhb_airlines-bounce@xxxxxxxxxxxxx [mailto:jhb_airlines-bounce@xxxxxxxxxxxxx] On Behalf Of Mike Lucas Sent: 14 October 2005 19:29 To: jhb_airlines@xxxxxxxxxxxxx Subject: [jhb_airlines] Re: Autopilot APPR HOLD problem


bones

I'm afraid I don't know what it is I'm looking for in the panel and
aircraft.cfg files ...

Panel.cfg contains the line -

gauge37=fsd_generic.ap.appr,  213,517,20,23

which suggests to me that there should be a working APPR_HOLD function.

As regards the GoFlight autothrottle, I have disabled the "arm when CMD
is activated" option.  But I cannot get the IAS/Mach hold to work from a
P8 button.  The appropriate P8 light comes on but it doesn't activate
the IAS/Mach hold (yes, I have designated the correct function in GF
config).  I can only get IAS/Mach hold to work using Ctrl+R.  Any ideas??

Going back to the Cessna Citation specifically, I found the following in
aircraft.cfg -

[Reference Speeds]
flaps_up_stall_speed=77.0      //Knots True (KTAS)
full_flaps_stall_speed=80.0    //Knots True (KTAS)
cruise_speed=262.0              //Knots True (KTAS)
max_indicated_speed=350.453125
max_mach=0.75

Surely flaps up stall speed should be higher than full flaps stall
speed?? - and I would have expected both to be 100+ kts.

Confused.

Mike L

Bones wrote:

First thing to suspect is the panel because it suggests the autopilot
gauge it uses may not be working properly. If it works in other
aircraft but not the C550 then it may be the interaction between the
panel and the aircraft.cfg file. In my copy both the autopilot and
autothrottle are flagged as available.

Check the MCP options in the GF Module. You should have two radio
buttons which enable/disable autothrottle with AP activation. I don't
actually use this myself as there are times when I want to keep AT
active when flying manually and so I have one of the T8 switches set
for AT engage/disengage. This works perfectly well. The command you
want is called AP_AUTOTHROTTLE.

bones

-----Original Message-----
From: jhb_airlines-bounce@xxxxxxxxxxxxx
[mailto:jhb_airlines-bounce@xxxxxxxxxxxxx] On Behalf Of Mike Lucas
Sent: 14 October 2005 16:09
To: jhb_airlines@xxxxxxxxxxxxx
Subject: [jhb_airlines] Autopilot APPR HOLD problem


For one sector of my FPI session on Wed evening I flew the Cessna Citation by VENEAVIONES in JHB livery, with panel by Brian Williams. Unfortunately, I discovered that APPR HOLD didn't work (at EGTE). Can someone with more expertise than me in this area tell me if this is a problem somewhere in one of the config files (aircraft.cfg or panel.cfg?) that can be easily fixed?

Still coming to terms with the new GoFlight autopilot module, in
particular the apparent lack of an autothrottle arm switch.  Only an
IAS/Mach Hold and although I have configured one of my P8 buttons as
A/Thr Arm it doesn't seem to activate and I have to resort to Ctr+R -
which rather defeats the purpose of this all-singing, all-dancing
autopilot module (I can even get BBC2 on it .... <g>)

Mike L








Other related posts: