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Glide Slope Issue

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Glide Slope Issue

Postby Robertfm » Sun May 26, 2019 2:37 pm

I have been flying a Diamond 40 Twin Prop plane and it's very responsive, however when using AP/Nav1 GS on approach it randomly seems to bring the plane down to ground too early. Other times it works fine.

I have the recommended approach/flaps etc and follow it but it still does it. Anyone any ideas.

Other planes I fly are not an issue.
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Re: Glide Slope Issue

Postby V12 » Mon May 27, 2019 2:26 am

Badly implemented AP routine. Many FG aircrafth have similar problem :( Activate GS mode only when vertical ILS indicator is centered.
Other problem should be false or reflected ILS GS signal in the mountains airports. Solution is simple - use rule 1:3 - if You are 3 nm from ILS transmiter, You should be 1000 feets above ground with centered ILS indicator. If the indicator is not centered, do not use GS autoland and land manualy.
This rule works from Cessna 172 to B52, A380 or Concorde too.
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Re: Glide Slope Issue

Postby dilbert » Mon May 27, 2019 12:57 pm

Just now flew Diamond 42 twin on route KNPA 17 to KNPA 70, without encountering the problem you have described. Only thing I noticed was that closely
setting throttle to ensure constant airspeed on final was absolutely necessary. Otherwise, it would gradually bleed off toward a stall. I had it fixed at 85 K,
which worked fine on the glide slope. :)
Last edited by dilbert on Mon May 27, 2019 1:55 pm, edited 1 time in total.
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Re: Glide Slope Issue

Postby Robertfm » Mon May 27, 2019 1:39 pm

I mentioned the wrong plane it's Diamond 42. I post again, but it appears to have disappeared. I have landed the plane a couple of times this morning without any issue. Really strange. Maintaining speed is an issue but I have made sure it doesn't alter on Final.
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Re: Glide Slope Issue

Postby dilbert » Mon May 27, 2019 2:30 pm

Aah. I don't normally click the velocity control box; having found throttle controls velocity well without doing so. If I do click it after route manager and autopilot are engaged, power drops off unexpectedly to idle. Found this out because I generally activate route manager and autopilot on runway (contrary to the WIKI); and if I do so with the velocity control box clicked, engine drops to idle. Are you clicking the autopilot velocity control box? If so, try leaving it blank.
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Re: Glide Slope Issue

Postby Robertfm » Mon May 27, 2019 3:46 pm

I actually set AP after I have climbed to over 1000. I set vertical speed before take off. Then after 1000 I set GPS Direction and then I set altitude hold once I reach it. Take off has never been an issue.

Landings are going well today (famous last words). Thanks for the advice.
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Re: Glide Slope Issue

Postby Robertfm » Tue Jun 04, 2019 3:51 pm

Flying into Dublin on runway 28 today again when activating GS approach plane suddenly just dipped 90 degrees down. I recovered it and landed manually. What I have noticed is that Dublin has 3 different GS/ILS frequencies. According to the info I was on the wrong one. FGNMP only shows one frequency. Next time I will use correct one and see what happens.

Edit: Flew back to Dublin and used correct GS/ILS 111.35 and landed without incident. So clearly FG is set up with all 3 frequencies as listed elsewhere but not on NMP
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Re: Glide Slope Issue

Postby wkitty42 » Wed Jun 05, 2019 10:59 am

what is FGNMP and/or NMP?
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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Re: Glide Slope Issue

Postby Robertfm » Wed Jun 05, 2019 12:39 pm

The FG look up Nmap which shows airports and all relevant frequencies etc.
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Re: Glide Slope Issue

Postby V12 » Wed Jun 05, 2019 5:12 pm

Similar problem is at JFK rwy 04 and 22. 13 and 31 are OK.
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Re: Glide Slope Issue

Postby Robertfm » Wed Jun 05, 2019 5:18 pm

https://apxp.enif.uberspace.de/ I now use this site as well which seems to list all GS/ILS frequencies for each runway.
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Re: Glide Slope Issue

Postby wkitty42 » Wed Jun 05, 2019 5:47 pm

i still do not recognize the term "Nmap" but that's ok... i won't push it...

i use the location menu to find the freqs for various services for airports... if what i'm looking for doesn't appear there in the sim, i use the sectionals map overlay in the Phi web interface into the sim... it is local and similar to the multiplayer map in that it shows me my craft, route, and AI craft in the sim...

the thing about using external sites for this data is that if the freqs have changed since FG's world scenery was built 5 or so years ago, then the data may be right but it won't help with FG being out of date... it might be possible to add this updated information to FG but that may cause other problems if the scenery needs to be rebuilt to properly use it for your flight...
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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Re: Glide Slope Issue

Postby Robertfm » Wed Jun 05, 2019 6:17 pm

All I can say when I used the eternal site frequencies now on 2 occasions they have worked. Perhaps it's just a case of they've been missed off on FG data.

I also use the PHI map I didn't realise the airport data was there. Just took a look. Thanks. Sorry about the NMap thing it's MPMap
Last edited by Robertfm on Wed Jun 05, 2019 6:52 pm, edited 1 time in total.
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Re: Glide Slope Issue

Postby V12 » Wed Jun 05, 2019 6:29 pm

FG has very old data. If You use actual from external sources, You can fly into the problems. Use only built in data via locations and airports.
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