DC8-50(INS) ILS approach.

[anderscn]

Hello,

I don´t know if I overlook something or mayby this plane is particular sensitive to pre-ILS alignment.

But I have now tried several times to land this plane in Frankfurt (EDDF). Before I switch the AP over to ILS, I have manually aligned perfectly with the beam, 10-15 miles before the RWY, altitude approx. 2500 feet. As I then switch to ILS, the plane turns into a 30-45 degrees left or right bank, and nose dives into the ground!

I have ILS approached this same RWY with other planes, with no problems.

Any ideas about this kamikaze behavior?

BR,
Anders

[jimhalinda]

I still have non-INS DC-8 panels, so I don't know how they work. But do they still have a GPS unit in them? If so, make sure your GPS/NAV is set to NAV.

When I leave it in GPS mode and then try approach mode on the autopilot, I get a similar behaviour to what you're describing.

Just a thought.

Regards,

Jim

[Dan K. Hansen]

I was about to say the same, but as it such a long time since I last flew, I couldn't remember, but I'm pretty sure that you either forgot to set the knob in NAV-mode, or had dialled a wrong frequence than the ILS has.

In either case, you shouldn't have to have the knob in GPS at all, if you are flying the INS ... you should just keep it in NAV mode for all I know.

[aerofoto - HJG Admin]

But do they still have a GPS unit in them?

"NO" .... GPS was taken of the DC8 panels .... years ago .... before even our administration of this website from April 2006. In fact none of the new HJG DC8 panels (when I say new I mean the generation we currently featur .... but which we have modified quite extensdively by us since 2006) have ever featured GPS since they were first released around 2002/3.

"IF" .... he's flying the the ILS with an aircraft that's too heavy then that's not going to help his case either. He should be planing his flights/fuel loads so as to arrive at his destination airport with no more than around 20% fuel remaining .... or .... slightly less than that. Airspeed management is also critical during both AP/ILS coupled .... and fully manual .... approaches to landing. Excessive speed during the approach will force the aircrafts nose "DOWN" whilst insufficient speed will cause it to then drift "UP .... even to the extent of obscuring forward vision of the RWY nbeing approached. Also .... he should be intercepting the ILS beam at no more than a 25 dregree angle .... and .... from more than 10 miles out too. I also need to say that FS ILS performance with any aircraft can vary quite a bit .... and .... is sometimes far from perfect. I have some aircraft/panels (not ours though) that fly the ILS beam perfectly .... all the way down to the RWY .... but .... I also have others which tend to loose the ILS beam by around 200 FT or so prior to landing. With these latter aircraft I generally disconnent the AP .... and then fly he approach manually from around 500 FT.

I've not, myself, encountered any particular difficulties flyiingh AP controlled ILS coupled approaches to landing using the HJG DC8's .... and the panels/FDE's we provide .... so long as the aircraft isn't being flown too heavy or too fast/slow.

I'm pretty sure that you either forgot to set the knob in NAV-mode

if you are flying the INS ... you should just keep it in NAV mode for all I know

OH BOY .... hints of KAL 007 all over again !

Mark C
AKL/NZ

[anderscn]

Thank you for the answers.

I think that I found the reason of the fault:
As I got to VOR distance of the airport, I navigated the rest of the way using VOR/NDB. Hence I switched OFF the INS on the MSU, rather that leaving it on NAV.

I redid the approach tonight with the same plane, but leaving the MSU on NAV - then ILS approach and landing with no difficulty.

Thus, even if not in use for the final of the flight, the INS should not be switched OFF, until all wheels are on the tarmac.

Best Regards,
Anders

[skyking]

I have yet to install the upgraded DC-8 panels with the INS, but having to leave the INS on during a coupled ILS approach is not necessary.....at least in the real a/c. We never turned them off until at the gate but they have NOTHING to do with automatic approaches. Again.....in the real world.

[Herman]

Hi Mark;

Just a comment regarding your statement about GPS and the DC-8.

I've beeen flying the HJG DC-8's for many years and the GPS has always been part of the DC-8 panel until the recent addition of INS,
( not certain if the GPS was eliminated when INS was added) as I have not used it at this point)

Herman

[Dan K. Hansen]

I think the procedures around the INS, is to calculate deviations and errors as part of the shut-down check list .... so INS should be turned off until safely parked at the gate... on blocks.

[aerofoto - HJG Admin]

I've beeen flying the HJG DC-8's for many years and the GPS has always been part of the DC-8 panel until the recent addition of INS,
( not certain if the GPS was eliminated when INS was added) as I have not used it at this point)

"NO" .... they haven't .... at least not in the form of the standard MSFS type GPS systems and which is what I interpret those folk (whom raise this subject) to mean.

From 2000 HJG used a completely different generation of DC8 panel .... this was back in the FS2000 days. That particular panel (with it's very MD80-ish looking combing) did feature an MSFS type GPS. I think that panel was by a Norwegian author.

Marco BALZAROTTI's DC8 panels were introduced during 2002/3 .... the current generation of panel, but again, these "NEVER" featured the MSFS type GPS system (as I'm sure Nick will recall because there was significant internal debate, at the time, regarding whether or not it should be included. The decision not to include it was made for the sake of accuracy/authenticity), but, these panels (DC8-50 first .... followed later by DC8-10, -60, and the -70 type panels) did introduce the KLN90B facility which is the closest piece of kit any of the 2nd generation of HJG DC8 panels has ever had.

I still have all of the original HJG FS2002 DC8 panels, along with all of their original F2004 updates too .... which is why I am able to communicate these details so definitively.

Some folk may have modded their original DC8 panels with MSFS type GPS themselves .... and which I know did happen. There was a lot of discussion regarding this on the old HJG forum between 2002 and 2005, but again, HJG DC8 panels, as released by this group .... and that's by both the original and our own current administration .... have "NEVER" included an MSFS type GPS system .... only the KLN90B system.

INS DC8 panel versions were only added to the group DC8 panels inventory during September .... 2 months ago !

Mark C
AKL/NZ

[Herman]

Hello Mark;

Enclosed is an image of a DC-8-40 panel. At the lower right corner is a navigational instrument clearly named " GPS "at the top left corner. I am not certain what type of GPS it is, but when it is engaged it does follow a GPS great circle route.

When on regular VOR navigation it also shows a CDI.

So if this instrument is not a GPS, what is it?

Herman





The CV-880 and 990 is also equipped with this nav device.

[Herman]

Just a little additional comment to the above Mark.

I realize that the GPS featured with the DC-8 panel is not at all like the standard MSFS GPS with respect to a moving map display, however, all other functions and displays ( GS,ETA,DTG,CDI etc.) are similar and this is what lead me to believe that the KLN90B is based on the GPS system. When selected it follows the exact GPS course of the MSFS selected route.
It also looks very similar to the Loran nav system I had in my Piper Cherokee.

Herman

[aerofoto - HJG Admin]

I realize that the GPS featured with the DC-8 panel is not at all like the standard MSFS GPS with respect to a moving map display

That's the GPS version that I've denying Herman .... the MSFS version with its moving map display !

In my haste to respond and within the very small windows of opportunities I often have to reply .... I possibly wasn't being as clear as I could/should have been .... even though I did state ....

the KLN90B facility which is the closest piece of kit any of the 2nd generation of HJG DC8 panels has ever had.

.... in relation to such GPS fascilities.

It's just that when discussing GPS ... the version we're most often asked/hassled regarding ;D is that MSFS version with its moving map display.

When I stated there's never been a GPS in any of those panels it's that particular version (the MSFS one) which my above commentary was actually intended to relate to ;D

Mark C
AKL/NZ