AI aircraft not landing

Hi guys,

I've never seen this strange problem before at any normal looking airport, with only flat terrain all around it and as far as the eye can see.

Approaching AI aircraft under IFR flight plans for HTDA's ILS RWY 5, seemingly approach the airport at 2200 feet but just fly over it at the same altitude, go around to try again but then disappear when above the airport a second time. All this can clearly be seen on a radar gauge installed in a military (test) aircraft parked alongside the runway.

HTDA is the "Julius Nyerere Intl" airport in Tanzania (East Africa) and which originally had the name "Dar-Es-Salaam" in it's default AP958340.bgl file. The installed third party airport scenery already had this new name in it's afcad file so, I consequently replaced the original name in the AP958340.bgl file with this new one and then re-compiled it. Nothing else was touched.

The pattern altitude in the afcad file is a normal 1000 feet and everything else in this file seems normal, as well as the airport scenery itself and the combination of them both. There are no faults found in the afcad file by the afcad fault finder process.

The AI aircrafts concerned vary between heavy Boeings and light GAs.

The next logical thing to try is an ATC controlled flight to HTDA myself and I'll certainly try that tomorrow when my eyelids have stopped being so heavy.

In the meantime, ideas anyone ??

Regards

Hans

I also watched an AI E190 not landing, I suppose the approaches are in error.

I will check them later

I replaced the ILS 05 approaches with the stock ILS 05 approaches and all is landing fine.

I have contacted Emmanuel with these infos.

Yes, hgschnell seems to be correct in his findings, the runway becomes blocked almost immediately after the first approaching AI aircraft is cleared for landing but that was only my secondary problem.

My primary problem somehow had something to do with the first approaching AI aircraft itself, which was seen (on radar) to be porpoising heavily as soon as it began slowing down for it's approach, more than 20nm away. Clearly an AI flight dynamics problem and I seem to have solved this after editing it's fore/aft load position within it's aircraft.cfg file. It now at least stopped porpoising and was even able to land quite normally, as were those following it.

However, how and why this load distribution correction was able to directly solve my initial non-landing problem, etc. remains very unclear. Moreover, any AI aircraft with such a serious flight dynamics issue should normally have crashed and disappeared somewhere along it's route and shouldn't even keep turning up where it does. Anyway, problem solved and that's what counts, even although I do not fully understand it.

Thanks guys.

Hans

Hans, are you sure it was a IFR flight to Rwy 05?

I watched several AI aircraft which could not land because of an approach in error.

They all were much to high close to the runway. I use "Tools - Traffic Toolbox - Explorer" and "Tools - Traffic Toolbox -Map" to watch and follow AI aircrafts (TRAFFICTOOLBOX_SDK).

I watched several AI aircraft which could not land because of an approach in error.

They all were much to high close to the runway. I use "Tools - Traffic Toolbox - Explorer" and "Tools - Traffic Toolbox -Map" to watch and follow AI aircrafts (TRAFFICTOOLBOX_SDK).

Hi,

Also, to make sure, you can use Traffic Toolbox to delete that aircraft in flight and check what other AIs are then doing. If they can't/won't land then it's an approach problem...

About AI FDE... I once read a discussion about that. From that I learned that for most AI devs (freeware/payware) FDE is an afterthought, as long as it has a nice flare on landing...

Regards,

DDP.

Hi hgschnell and DDP,

Yes hgschnell, my ex-porpoising AI B747 aircraft was flying an IFR flight plan, which, like so many others, was manually created via my TTools program.

The third party's HTDA's afcad data, including, as far as I can see, all it's navigation and approach aids, all seem completely correct. The only real afcad edit has been the airport's name change from "Dar-es-Salaam" to "Julius Nyerere Intl", also in my default AP958340.bgl file in order to prevent duplicate active airports with different names.

In the meantime I've checked and re-checked all related files and data but in retrospect the only edit which remains standing in the HTDA afcad file, is a previously missing right hand pattern turn related to RWY 5. However, I just cannot imagine that this tiny and seemingly non IFR related edit could be the actual solution to what is described as being an "approach error".

Anyway, all is well at my end now, both IFR and VFR AI aircraft are now landing at HTDA normally ..... but ..... why and how still remains a mystery in relation to my initial "AI not landing" problem.

I've seen other "AI not landing" issues before but those were all directly related to (default) mountains or at least "high ground", in the direct vicinities of the airfields concerned and in combination with local wind directions. However, there is no high ground near enough to HTDA to directly cause any such "AI approach" issues.

I've also seen third party AI aircraft seemingly take off correctly (at other airports) but not turning up at their destination airports. I consequently (test-)took off myself in one of my flyable aircraft and flew in formation with the AIs concerned, to find out what was happening to them.

Along their flight planned IFR routes it turned out that they were somehow not able to gain enough speed to sustain their climbs and they consequently "crashed" at varying distances from their take off runways. Initially substituting their AIR files by default ones of comparable aircraft directly solved most of these problems. For me this means that AIR files are definitely not always just "afterthoughts".

Regards, happy landings and stay healthy.

Hans

Hi Guys,

Thanks for all your reactions guys but my "AI aircraft not landing" problem was primarily caused by the first approaching AI aircraft (B747) being far too light in it's aircraft.cfg "empty weight" entry. After I had replaced this weight by that of the default B747-400, the whole problem was immediately solved.

I had also wrongly assumed this very unique problem to be structural and that it was somehow related to technical aspects of the HTDA airport, neither of which was the case.

Stay safe and regards.

Hans