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jammen737 View Drop Down
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    Posted: 27 Aug 2017 at 3:16pm
Hello!  1st, I'm loving the model, especially for the 1/2 off price.  I am having some trouble getting the 'ALTITUDE HOLD' to work on the DC-8-73F model. 

 I have the 3 A/P Servo switches turn on, Flight Director is turned on (although the switches are kinda wonky), A/P master switched is in the armed position (switched to Yaw Damper then Autopilot).  After getting airborne and stabilized, I have been successful in switching the AP SELECT to AUX NAV and capturing the flight path entered into the FMC.  During climb, I with the ALTITUDE knob into VERT HOLD position and use the VERT SPEED wheel to climb -/+ 3000 FPM etc.  Upon reaching cruising altitude ie 35000', I use the VERT SPEED wheel to feather the climb down to +100 until 35000' is indicated on the altimeter.  I then switch the ALTITUDE HOLD switch on the FD and nothing happens.  The aircraft will still continue to climb and descend without me constantly having to feather the VERT SPEED wheel to keep the aircraft at desired altitude.  I have noticed in the 3 dial windows right above the AUTOPILOT panel (below the throttles) that the center window says 60000'.  I don't know how to change this to have 35000' entered.  Perhaps my problem is there.  

I referenced the Just Flight DC-8 'fly with me' video on YouTube.  When he switched the 'ALTITUDE HOLD' switch ON, his aircraft immediately pitched to capture the altitude passing when he switched on.  I hope my explanation was detailed enough and hope that the fix is something easy like correcting pilot error.  Any suggestions are appreciated.  Also, I purchased this a/c on Aug 25th and are not sure if the Service Pack needs to be installed or not.  I have read the manual and seemed to have followed instructions in the Tutorial section.  
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aspen31 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote aspen31 Quote  Post ReplyReply Direct Link To This Post Posted: 03 Sep 2017 at 4:34pm
Hi
I have written about several issues with the DC-8 but have not received a response. I fly the 63 CF and have just written about autopilot issues - different that yours but similar impact. I may try to submit a support ticket as well.
Good luck with the airplane.
Warren
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jammen737 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jammen737 Quote  Post ReplyReply Direct Link To This Post Posted: 03 Sep 2017 at 6:17pm
Thx Warren. Let me know if you het anywhere. I'll stay tuned to your posts.
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aspen31 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote aspen31 Quote  Post ReplyReply Direct Link To This Post Posted: 03 Sep 2017 at 6:27pm
Hi
Not so far. I submitted a ticket to the customer service folks but nothing yet except a question about whether I am following the cold and dark start up (which I am to the best of my knowledge). Just tried another flight and same thing - autopilot appears to pick up a heading and maintain and altitude (with vertical speed hold) but then seems to go nuts and won't maintain anything. I am somewhat familiar with this type of autopilot from other similar era FS aircraft but don't recall many issues. So far it works better if I don't attempt any autopilot use and just fly manually but over time that is tedious to say the least. By the way I use Prepar3D v3.4.
Take care.
Warren
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Martyn View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Martyn Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 2017 at 7:50am
We are looking into these issues now and you'll receive replies to your support tickets as the investigation progresses.

Thanks
Martyn
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Martyn View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Martyn Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 2017 at 9:47am
Quote Upon reaching cruising altitude ie 35000', I use the VERT SPEED wheel to feather the climb down to +100 until 35000' is indicated on the altimeter.  I then switch the ALTITUDE HOLD switch on the FD and nothing happens.  The aircraft will still continue to climb and descend without me constantly having to feather the VERT SPEED wheel to keep the aircraft at desired altitude.  I have noticed in the 3 dial windows right above the AUTOPILOT panel (below the throttles) that the center window says 60000'.  I don't know how to change this to have 35000' entered. 

The autopilot has probably changed a fair bit since the YouTube footage was recorded. To get the autopilot to hold a certain altitude, you now need to rotate the VERT SPEED wheel to select 0ft/min (level flight). The altitude hold switch on the FD panel only affects the flight director and has no impact over the autopilot. There is also no longer the ability to select a specific altitude to hold (like on the real aircraft), so you can ignore the 60000' readout and just select 0ft/min. 
Martyn
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aspen31 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote aspen31 Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 2017 at 10:48am
Hi Martyn
Selecting "0" FPM seems to have only a random effect. I have experienced both the altitude holding properly and no effect at all - sometimes climb and sometimes descent. I cannot correct this by manipulating the Vert Speed wheel. The only fix I have found is to disconnect and correct the V/S manually. I also have the servos selected "on".
Thanks for the prompt response.
Warren
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Martyn View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Martyn Quote  Post ReplyReply Direct Link To This Post Posted: 05 Sep 2017 at 8:31am
Hi Warren,

I can't reproduce this issue. With the autopilot engaged, VERT HOLD selected on the ALTITUDE knob and 0ft/min selected on the VERT SPEED wheel, the autopilot continued to hold the altitude for several hundred miles.

Our support team will continue to investigate via your support ticket.

Thanks
Martyn
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aspen31 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote aspen31 Quote  Post ReplyReply Direct Link To This Post Posted: 05 Sep 2017 at 11:15am
Hi Martyn
Yesterday I flew the airplane for quite a while this time using the FMC and everything (accept perhaps my airmanship) worked well. The only difference being that I selected NAV with the GPS / NAV switch. Will the autopilot track a GPS flight plan and if so what mode selection on the autopilot should be used?
Thanks
Warren
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Martyn View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Martyn Quote  Post ReplyReply Direct Link To This Post Posted: 05 Sep 2017 at 1:15pm
Hi Warren,

I used the autopilot to track a GPS flight plan during a test flight yesterday. Engage the autopilot, select GPS on the NAV/GPS switch and then rotate the mode select knob to VOR/LOC (or press Ctrl+N). The autopilot should then hold the GPS flight plan.

Thanks
Martyn
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aspen31 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote aspen31 Quote  Post ReplyReply Direct Link To This Post Posted: 05 Sep 2017 at 1:57pm
Thanks Martyn
Rainy day here in the Adirondacks so I'll have time to play with the autopilot.
All the best
Warren
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aspen31 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote aspen31 Quote  Post ReplyReply Direct Link To This Post Posted: 05 Sep 2017 at 5:41pm
Hi All
I tried another long flight and used 2 flight plans - both GPS and FMC. The A/P 
worked for the most part really well but when I switched from FMC to GPS  the 
A/P seemed to lose it's ability to maintain altitude. I switched everything off 
and then back on after stabilizing the airplane and everything seemed to work 
again. Not sure exactly why this is happening but I'll keep working on it. Seems 
a bit "buggy" just like the old DC-8s. 
Thanks 
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jammen737 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jammen737 Quote  Post ReplyReply Direct Link To This Post Posted: 06 Sep 2017 at 1:24am
Originally posted by aspen31 aspen31 wrote:

Hi All
I tried another long flight and used 2 flight plans - both GPS and FMC. The A/P 
worked for the most part really well but when I switched from FMC to GPS  the 
A/P seemed to lose it's ability to maintain altitude. I switched everything off 
and then back on after stabilizing the airplane and everything seemed to work 
again. Not sure exactly why this is happening but I'll keep working on it. Seems 
a bit "buggy" just like the old DC-8s. 
Thanks 

I too just tries a flight PSP-PHX.  Had to constantly feather the VSI.  Also noticed on the National Cargo model that the '7' key would not work on the FMC.  2nd time I have tried this and the 7 key would not work.  Kinda disappointing in the Just flight model.
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Martyn View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Martyn Quote  Post ReplyReply Direct Link To This Post Posted: 06 Sep 2017 at 9:47am
I didn't attempt to switch from the FMC to the GPS so I'll give that a go.

Quote Had to constantly feather the VSI

How much is your altitude deviating from the selected value by? Is that with clear weather? As I mentioned above, the autopilot is holding the selected altitude perfectly for me.

Quote  Also noticed on the National Cargo model that the '7' key would not work on the FMC.  2nd time I have tried this and the 7 key would not work. 

We're currently waiting for an updated gauge from the external developer of the FMC.

Thanks
Martyn
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aspen31 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote aspen31 Quote  Post ReplyReply Direct Link To This Post Posted: 06 Sep 2017 at 11:35am
Hi Martyn
When I experienced the altitude, V/S "0" loss the airplane simply went into a dive, perhaps 2000 FPM. I shut the autopilot off, stabilized the airplane and turned it back on. Everything recaptured. In the last instance this seemed to occur when I switched from the FMC to GPS flight plan.
Thanks
Warren
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Omid View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Omid Quote  Post ReplyReply Direct Link To This Post Posted: 30 Dec 2017 at 3:23pm
Originally posted by aspen31 aspen31 wrote:

Hi Martyn
When I experienced the altitude, V/S "0" loss the airplane simply went into a dive, perhaps 2000 FPM. I shut the autopilot off, stabilized the airplane and turned it back on. Everything recaptured. In the last instance this seemed to occur when I switched from the FMC to GPS flight plan.
Thanks
Warren


Hi
Exactly identical problem with V/S and switching FMC to GPS modes!!!
By the way, where is the Alt Hold switch in 63, 63CF, and 62?
I don't seem to find any altitude holding switches on the front panel or anywhere else in these three models.; however, if I'm lucky and the V/S doesn't go mad (as noted by several people here) a V/S of 0 will hold the altitude for me.


Regards-Omid
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Blaunarwal View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Blaunarwal Quote  Post ReplyReply Direct Link To This Post Posted: 05 Jan 2018 at 4:53pm
I recently posted several bugs of the DC-8 series in the support section, got a ticket and Craig answered me:

Unfortunately we are no longer going to be making any changes to the DC-8. The aircraft developer has stated that as this aircraft is too old and many aircraft have been developed since they cannot put on hold current developments and as such no further service packs will be created for the DC-8.

I was a bit astonished and also dissappointed, since they just released a P3D4 compatible version, to sell it further and just stop any development. On the other hand, this aircraft is here since end of 2013  and still has such bugs and even more obvious ones, which never had been fixed.

So this aircraft is still beta and will never be perfect. 
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