[jhb_airlines] Re: Autopilot APPR HOLD problem

  • From: Gerry Winskill <gwinsk@xxxxxxx>
  • To: jhb_airlines@xxxxxxxxxxxxx
  • Date: Sat, 15 Oct 2005 19:21:29 +0100

I'll hold off tweaking until you've had a look.

Gerry Winskill

Bones wrote:

It sounds almost as if you are talking about a totally different aircraft to
the one I fly! The C550 flown manually is a real softy and I can fly visual
circuits in it without any problem. As mentioned on the web page I did
increase aileron authority a bit because roll rate was awful but I have
otherwise made no tweaks.

The other comments you make seem more related to the autopilot functions but
I will test my version again to make sure. I've not had any problems so far
capturing speed or the glidepath.

I might just delve into the .air file because I agree that rolling left
seems faster than rolling right. This may be due to incorrect values for the
aileron ratios.


-----Original Message-----
From: jhb_airlines-bounce@xxxxxxxxxxxxx
[mailto:jhb_airlines-bounce@xxxxxxxxxxxxx] On Behalf Of Gerry Winskill
Sent: 15 October 2005 17:52
To: jhb_airlines@xxxxxxxxxxxxx
Subject: [jhb_airlines] Re: Autopilot APPR HOLD problem

I've downloaded tis aircraft, used the FS Panel Studio panel ant tried a flight. Only two comments. I think it may be a bit overpowered, since AutoThrottle couldn't reduce sufficiently quickly to stop it exceeding 240 kias, in the initial climb. Approaching IOM, it captured the Localiser very efficiently, usin APPR. From then on it was downhill. When it caught the Localiser, still below the Glideslope, and with Alt Hold still selected, it started to descend, rapidly, from the setting of 2500'. It's not the only a/c to do this. No idea why. Things then got worse. I tried to fly the ILS manually. Maintaining GS was no problem. The Localiser was a different matter, since at what I thought was a high finals speed of 120 kias, any turn to the right needed full right ailerond AND full right rudder pedal. Once the speed was taken to about 130, full aileron authority returned though, unlike the real aircraft, it still needed full deflection to initiate turns.

Gerry Winskill


Bones wrote:

Give me the name of this panel and I'll download it and have a hunt
around. If the autopilot is an XML file I should be able to track down
why the APPR button isn't working. OTOH if it's and old GAU file then
that's beyond my abilities as I have no C++ skills.

I've built an autopilot for the Aztec and the code is very simple. An
APPR button isn't very hard to do so I could probably add this to the
Citation if the original is faulty.


-----Original Message-----
From: jhb_airlines-bounce@xxxxxxxxxxxxx
[mailto:jhb_airlines-bounce@xxxxxxxxxxxxx] On Behalf Of Mike Lucas
Sent: 15 October 2005 12:48
To: jhb_airlines@xxxxxxxxxxxxx
Subject: [jhb_airlines] Re: Autopilot APPR HOLD problem


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


-----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


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

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)

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


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.


-----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

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