Author Topic: A320 problems  (Read 5268 times)

Offline EHM-2198 Didimo

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A320 problems
« on: December 04, 2007, 04:51:11 pm »
I was test flying this A320 just now and have found two problems:

1. The Barometric pressure gauge does not work well. The hotspots are displaced. You can however by playing around have it change between InHg and mb but to get it to actually CHANGE the barometric setting (increase/decrease) is nearly impossible.

2. Never had a problem recovering from stalls but with this one quite a drama! Even after you try to level it to recover from the stall the thing just plumets straight down to the earth's core! Was at 19000' when I took it to a stall and when I tried to recover it it could not level (power was ok), it just plummeted incontrollably to the ground, what a crater!

3. Seems a bit overpowered, when taxiing even when the throttle is IDLE and you press brakes (not to stop completely) it keeps on an on and on as if throttles where engaged a little bit more than IDLE. Never had this problem with any other a/c in my hangar.

The first time of the flight FS9 crashed on me during the climb, it simply disappeared from the PC address space. Had to start all over again (what a pain).

Anybody have these problems with the A320?

My monitor is at 1280x1024 which is the resolution of the panel.

Offline EHM-1465 Dominic

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A320 problems
« Reply #1 on: December 04, 2007, 05:00:37 pm »
Never had problems like that with the A320...

Can you give a bit more information on your system set-up please such as processor, operating system, RAM, graphics card etc? And do you have any hardware such as yoke/pedals/throttle unit attached? All these details can help to pinpoint technical reasons behind some problems ;)

Also can you confirm which A320 you are using - freeware or the payware one?

Thanks :P
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Offline EHM-2198 Didimo

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A320 problems
« Reply #2 on: December 04, 2007, 05:55:43 pm »
I had the freeware version of the A320 for FS2004.

I have a CH Products yoke as well as the pedals (both USB), my throttle is integrated in the CH Yoke.

My processor Pentium 4, 3.0 GHz with 1 GB of DRAM running Windoze XP Pro SP2 with all known updates. My graphics card has never given me problems, it is an nVidia 5200 with 256MB of (non-shared) memory.

Offline EHM-1465 Dominic

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« Reply #3 on: December 04, 2007, 06:16:33 pm »
Well, no clues there then...

I can't think of an obvious reason for your problems although thinking about it I've always used the A320 aliased to my PSS panel so perhaps Robert will have some ideas...

Sorry! :[
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EHM-2029 Sotiris

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A320 problems
« Reply #4 on: December 04, 2007, 06:47:03 pm »
I can also confirm that I never had problems with the A320.
One thing regarding the idle power rolling.
Even on the real Airbusses, idle power is enough to keep your plane rolling ahead. Only when it come to cornering do you need to apply any extra throttle.

Offline EHM-2097 Andrei

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« Reply #5 on: December 04, 2007, 08:58:03 pm »
Hi Didimo,

I can confirm about the barometric pressure gauge, I find too that it behaves strangely, but it looks to me more like an unexpected feature ;D than an actual bug.

I think there are two hotspots on that gauge:
- one that switches between milibars and inches;
- one that switches to standard 1013 milibars pressure ABOVE 18000ft. Below this level it does nothing.

If this is true (and not mixed up by my imagination :) ), the correct way to use this gauge is wait until 18000ft THEN use it to switch to standard pressure. I have done this while flying online and it works (still, if any doubt persists, can anyone confirm or infirm this behaviour?).

However this is bad for Propilot flights, it means you only have a split second when reaching 18000ft to switch pressure before getting penalized. Or fly in fair weather...

I can't tell much about the other problems you encountered. Never tried to get it stalled and for taxiing I cheated = fitted it with the ground panel which autocontrols ground speed.

Cheers
Andrei
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EHM-1821 Javier

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A320 problems
« Reply #6 on: December 05, 2007, 06:58:56 am »
I'm using the freeware Ken Mitchell panel with the Ifdg A320, i cant find the hotspot to manually change the pressure gauge either, so i just press "b" :]

I just tried stalling the aircraft at FL340, the aircraft sinks like a brick! i fell from FL340 to 200 in less than a minute, only recovered when the airspeed reached 330KIAS, and by the time i recover, i'll be overspeed :% so the verdict is, recover as fast as you can once you hear the stall horn or you'll suffer a horrifying dive:]

and about the A320 being overpowered, I dont think it is. I installed the ACS panel for the MD-11 a few days ago and it also includes a edit to make the plane feel real on the ground. When i tested out its braking, it felt pretty much like the A320, slowly coming to a stop, so i don't think it is a problem, maybe a realistic addition, not sure how the A320 brakes in real life though :s

Offline EHM-2198 Didimo

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A320 problems
« Reply #7 on: December 05, 2007, 08:31:31 am »
The barometric gauge is unfortunate because you expect your hotspots to be on the correct place, otherwise you spend time clicking like a madman taking away your concentration for more important things. Also, if you are below TA and instructed to change your barometric setting then you are at a loss. I find that quite disturbing.

The idle power thing is not a problem for me, just wanted to mention it.

The stalling is quite disturbing, mine plummeted from FL240 to under ground level in around 30 seconds. Never had problem recovering from a stall until this one. When it plunges down it does not even respond to you pulling up the yoke (elevator up). This incident however reminded me an episode of CRASH INVESTIGATION in which a Russian airline was flying their brand new Airbus from Russia to near Japan and the captain brought his son & daugther to let them play with the yoke. It was in autopilot, little did they know that even in autopilot if you pull/push/turn the yoke too "persistently" then the computer overrides the autopilot and assumes/d you want to take control. At night and such as speed they did not notice they were turning and then the a/c went down like a brick and they could not bring it up and.... CRASH...

NEW ISSUES DISCOVERED:

- When autopilot is set and have plan is known when you enable the GPS button on the panel the AP does not follow the route on the GPS. The GPS button appears to me only animated (on/off) but not really operational.

- Controlled descent appears not to work unless I did something wrong. I was at 25000 and wanted to do an automatic controlled descent to 13000. Set new (lower) altitude, enabled ALT and AutoThrottle (AutoPilot was ON), it appeared to descent but not at the calculated rate and the auto-throotle was not really working because it remained at 80%. I had to disable it and do it manually after the test (throttle to idle).

Offline EHM-1001 Robert

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« Reply #8 on: December 05, 2007, 07:52:16 pm »
Well,

it is strange as we are talking about a stall. Maybe the Stall warning comes too late, but I do not know many planes that can recover from a Stall so easy as you want. I do not mean the moment when the horn starts shouting... I mean the moment when the plane already bowed and start falling down. In this case your only chance is to gain speed and "Pull up in time !..."

If there is not enough thrust but the autopilot tries to keep her up i nthe air, yes it will almost stop before falling down...but will fall down like a brick ! If you drive it with your hands, you can recover a stall easily, but the autopilot will not do it ! It will do its job and follows YOUR commands: it will keep try to climb even without thrust...why do you feel it is strange ???

Not the autopilot should recover nicely from a stall, but the pilot should be wise enough to not push his plane until stall ! Un fortunately there is not Fly-by-wire yet in FS, so its up to the pilot. ;)

BTW, how could you stall it at all unwantedly ? IF you see a large jet losses speed and it goes under 200kts you need to level it immediately to gain speed again. You need to take care about the payload too, and you should not want to push her up to the ceiling limit right after takeing off with MTOW ;)

And yes, some lighter jets (even B737) rolling at idle power ! But not the A320 ! You might have some bug around your throttle settings.

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Offline EHM-2198 Didimo

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« Reply #9 on: December 05, 2007, 10:43:18 pm »
I was test flying the thing. It is possible to make it happen, in fact I induced it yet again.

I placed it in autopilot (AP+ALT+VS) throttle around 75% I think. The nose was slightly up. After a while I noticed the nose was too much up (pitched up), around 30 degrees which is not natural for level flight.

Then I added the auto-throttle thinking that since it would AT it would not need to pitch up to go level. Hum... WRONG! after a little while the thing went into a STALL.

Yes, of course I know how to recover from a stall and I have NEVER EVER tried to recover from a stall with an Autopilot on.

Then it started to stall, in a matter of seconds it started falling down like a brick in a nearly uncontrollable spin. Down, down. As soon as that happened I disabled AP.

still going down like a brick, since it was upside down I had to abuse my yoke to try to bank it 180 degrees, was not so easy as it tended to go belly up again. In a matter of seconds (don't ask how many, I was busy recovering from the thing) it dropped 12000 feet. The clue in recovering from this mega stall (and a postmortem black box would have shown it) was to reset the pitch. I noticed that the AP had moved the elevator trim to pitch up +15.0 !

By this time the plane is at overspeed (some 400 knots) so another situation to recover from.

Finally at 8,000 I had the plane under control. So here, massive altitude drop, nose down dive, uncontrollable spin during dive, overspeed.

Believe you me, NOT something I would like to experiment in real life!!!! nevertheless I think:

a) There is possibly something wrong with the algorithm used by the autopilot which causes too much positive feedback thus enlarging the problem.

b) Even though it is simulation it IS stressful but wow, what a way to polish up simulation skills! If I could only had "saved the flight" during the spin I could have it for a training session!

I think I will try it some more with and without auto throttle. Anyway, I am loving this airbus, so far I had been a Boeing 737/767 sim driver :)

Offline EHM-1001 Robert

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« Reply #10 on: December 05, 2007, 11:33:22 pm »
Well,

jet pilots (as far as I know) use different climb tactics: basically the A/T is always ON.

When climbing above 10000 ft, climb rate is reduced a bit from +2000...3000 fpm down to +1000, and they gain speed of around 300...320 kts. Then, the role is to keep this speed through the climb. You need to adjust your V/S according to the speed, thus the airplane could keep the 320 kts. A typical climb profile could be (depends on actual plane and payload):
+2500 fpm until FL150
+2000 fpm until FL200
+1500 fpm until FL250

When the airplane reaches FL250, the A/T is switched to MACH mode, and the cruise speed is set, say M0.83 From this time they hardly go over +1000...1500 fpm, and slowly decrease it so much on the last few thousand feets, that the aircraft climbs only with +500fpm. Speaking about THEY, they ususally means the FMC or FMS computer in reality, but you can always spin your knobs in FS by yourself.

At EHM we tune the flight dynamics, until the aircraft is able to fly that climb profile. For this we need to tune engine power, and aerodynamics charts. If you feel your airplane could not do this profile, then something probably wrong with your FS.

And if you be able to fly that profile, and keep an eye on your speed, you will not get into 30 degrees nose up situations. Any plane that is reaching 30 degrees up will soon fall down like a brick...maybe not if it was a Red Bull acrobatic plane ;D

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Offline EHM-2198 Didimo

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« Reply #11 on: December 05, 2007, 11:45:47 pm »
Hey Robert thanks a lot for that new insight into the climbing profile. Normally I do the climbing myself and only engage the AP when I reached cruise altitude but I am going to try this.

Thanks again!

Offline EHM-1001 Robert

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« Reply #12 on: December 06, 2007, 06:18:57 pm »
Your welcome ;) If you can afford to buy and try some payware aircrafts, you can learn a lot from their behavior in the air ;)

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EHM-2204 Dmitri

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A320 problems
« Reply #13 on: December 15, 2007, 07:45:09 am »
I use a payware A320. Usually I set Optimum climb after engine out ALT. She climbs at about 2400 fpm and reduces climb rate the closer you get to crz alt. With regards to stalling, I have done it. How I recovered was , AT off, AP off, Throttles IDLE, Nose down and once speed established, AT on AP on, set SPD. I have on occasion had to manually fly as the AT would not re-engage for some strange reason.

Taxxing. I use thrust of about 40% N1 to get rolling and then Idle. She rolls at about 23 kts. Corners should be between 10-15 kts.

 

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