A320 IAE Initial Climb Performance

[Cheyenne Chief Pilot 829]

Yes, OK, the speed is to low for climbing but why does the engines give no more speed?

All Iw nat is to make an takoff with IAE engine without stall. No chance. With CFM no problems.

Martin,

I've been having a tough time recreating your issue. Just tried a takeoff with your weight (well, not your weight, but your aircraft's weight of 67.4 tons ) and EAI/WAI on. With the A/P engaged shortly after liftoff, my speed would not drop like yours, so no stall protection kicking in for me.

Could you pls. tell us something about the stuff going on before and after your liftoff? Things like rotation rate, airspeed at liftoff, speed when you are engaging the autopilot ... stuff like that. Best to hit the 'V' key a couple of times during your takeoff, so the numbers can be looked at later on. Thanks!

[Martin Müller 39]

Martin,

I've been having a tough time recreating your issue. Just tried a takeoff with your weight (well, not your weight, but your aircraft's weight of 67.4 tons ) and EAI/WAI on. With the A/P engaged shortly after liftoff, my speed would not drop like yours, so no stall protection kicking in for me.

Could you pls. tell us something about the stuff going on before and after your liftoff? Things like rotation rate, airspeed at liftoff, speed when you are engaging the autopilot ... stuff like that. Best to hit the 'V' key a couple of times during your takeoff, so the numbers can be looked at later on. Thanks!

TOW 67300.jpg

In clear weather it also works for me.

Try it under real weather. I used LROP Takeoff RWY 08L and ASN Real weather.

If you have absoloutly stable conditions (no turbulences), than the problem does not occur.

[Cheyenne Chief Pilot 829]

In clear weather it also works for me.

Try it under real weather. I used LROP Takeoff RWY 08L and ASN Real weather.

If you have absoloutly stable conditions (no turbulences), than the problem does not occur.

Yep, that makes sense:

When landing in clear weather, I got close to the protected speed area already. Add some changing winds or the FSX sort of turbulence and ...

Weather could introduce two kinds of problems:

1. unrealistic stuff thrown at you by the sim
2. the way the Airbus autothrottle tries to cope with sim weather

The bus' A/THR has been tweaked for turbulence already; this additional issue we are facing here may require some internal discussion, I reckon.

[Cheyenne Chief Pilot 829]

My real weather of course varies from yours, so it's still a bit of a challenge to replicate your issue:

Had some moderate turbulence here, but the takeoff and climbout went fine:

[Martin Müller 39]

My real weather of course varies from yours, so it's still a bit of a challenge to replicate your issue:

Had some moderate turbulence here, but the takeoff and climbout went fine:

Real wx.jpg

Try follow departure:

LROP / RWY08L / SOKRU1A

[Aerosoft Team [Inactive Account] 51558]

Try follow departure:

LROP / RWY08L / SOKRU1A

Martin, the departure should be matter for the issue you seen, the way the weather is interpreted is. That is different on your system then it is on ours. No idea why.

[Martin Müller 39]

Martin, the departure should be matter for the issue you seen, the way the weather is interpreted is. That is different on your system then it is on ours. No idea why.

I'm not alone with the problem I think.

[Aerosoft Team [Inactive Account] 51558]

I'm not alone with the problem I think.

Yet if all the tens of thousands of customers would see the same issue as you I would think this forum would look a lot different, would you not agree? We are looking at this issue (to see if there is an issue for starters) and will work on it when we find something to fix. But when our real world pilots and our beta testers do not feel this is a major issue it is not high on our list.

[Martin Müller 39]

Yet if all the tens of thousands of customers would see the same issue as you I would think this forum would look a lot different, would you not agree? We are looking at this issue (to see if there is an issue for starters) and will work on it when we find something to fix. But when our real world pilots and our beta testers do not feel this is a major issue it is not high on our list.

I have no problems with CFM engines. This Problem exists only with the IAE Model of Airbus 320. I don't know in which lane I shoud search the reason of failure. It seems like a a problem with engines to provide enough thrust to get and hold V2. I don't know why.

[Cheyenne Chief Pilot 829]

Different runway, different SID, different weather - still an uneventful takeoff for me.

A number of things could be different for you: frame rates, takeoff technique, degree of turbulence, settings within your weather engine ... and the list goes on.

• Best to make sure you have high fps. (If in doubt about your frame rates: Save your current graphics settings to a profile and then try scaling your settings down. You can restore them later by loading the profile again.)
• Also start your rotation immediately after the "Rotate" call, but still make it a slow, smooth, continuous rotation: 2-3 degrees in pitch per second.
• For a test try engaging the autopilot immediately after the "Positive rate" call; just to find out how the automation can cope with your initial climb and the following departure.

[Don Lee 6]

I just had the same problem 5 minutes ago, departed runway 11 LOWW with A320 IAE. Flap 1+F and pitch UP 0.7 set, 67 degree Flex thrust level set, gear up 200ft above the ground, it climbed to ~500ft then stalled for no reasons, everything looked normal but it couldn't climb and then crashed onto ground. The winds were 12011KT, takeoff weight was 63,477kg. As I booked the flight so I'm going to make it again, and this time, with a A320 CFM, will come back and let you know if it works with this one.

[Don Lee 6]

In the same conditions, it worked fine with A320 CFM. Also, there isn't any problem with A321 IAE because I've flown it a lot.

[mopperle 4162]

Did another testflight with the A320IAE and 66.5 tons TOW and have also no problem:

After Takeoff

after setting Climb thurst

So IMHO there are 3 reasons why you have problems:

1. something mysterious has happened in our last builds and the problem got solved by itself
2. you are doing something somewhere wrong
3. something is misconfigured on your PC/FSX

To rule out 1) simply wait for SP2 and if it still exists on your PC we can try to track down 2) and 3)

[SierraDelta 4]

... 67 degree Flex thrust level set, ...

That will give you very little power, something like 52-54 degrees would seem more reasonable.

[Airbus339 129]

That will give you very little power, something like 52-54 degrees would seem more reasonable.

With long runways 67 degrees is sufficient: there's no need to use more power

[Don Lee 6]

yes right, the runway was long, and actually I left the flex setting as how it was calculated by the CDU. Hopefully it's been fixed with the latest build.

[Airbus339 129]

I think also the IAE A319 has this issue: it's very difficult to make the aircraft climb when flying departures that require turns at low altitude. The aircraft seems to be a little underpowered until you switch to CLB thrust (which for me is ALWAYS higher that FLX?!?!). Even with light loaded aircraft it's impossible to climb after TO with more than 1400/1500 FPM

[Michael_LOWW 4]

Hey!

For me CLB thrust only seems to be very low until flap retraction which makes turns at low altitudes difficult. I mostly climb from the thrust reduction altitude at 1,500 ft AGL with flaps extended to 3,000 ft AGL for noise abatement. Only at 3,000 ft AGL I retract the flaps to pick up speed. After that the calculated thrust setting goes up and the vertical speed increases which makes the aircraft climb normally. I tried this procedure on the DARKE1A SID from VNKT runway 20 to OTHH this afternoon. Eventually, I had difficulties to reach 10,500 ft at DARKE because it took me so long to reach the flap retraction altitude. The take-off roll (with TOGA thrust) and the initial climb-out to 1,500 ft AGL were perfectly normal at a vertical speed of about 2,300 fpm. During the right turn at KTM VOR with flaps still extended and CLB thrust engaged the plane climbed at about 500 fpm. After flap retraction at 3,000 ft AGL the plane quickly picked up speed to 230 kts and climbed at a rate of about 2,600 fpm again.

Best regards,

Michael

[Aerosoft Team [Inactive Account] 51558]

Gents let's close topic until the service packs are released, a lot of things have changed in those and it could very well these problems are changed there. These service packs are expected first week of December.

[Michael_LOWW 4]

Gents let's close topic until the service packs are released, a lot of things have changed in those and it could very well these problems are changed there. These service packs are expected first week of December.

Hey Mathijs!

Thanks for the info! Looking forward to the release to make a great product even better.

Best regards,

Michael

[Joshua Che. 1601]

Let me make it clear:

1. The upcoming SP is to make sure we are using the same set of files. That does NOT mean anything has been done about this.

2. The thrust rating are as accurate as it can get. Unless there is credible data to support your claim, I can only ignore such claims.

3. There is no use comparing CFM56 to IAE. The A320 itself has different thrust rating for both variants. The two engines itself have different climb performance even at the same thrust rating.

4. FLEX rating calculated by the FMGS does not include obstacle clearance on climb out.

[Airbus339 129]

I'm not claiming the thrust is inaccurate, I'm only saying that the aircraft struggles to climb if a turn at low altitude is required. I don't know how realistic it is but I don't think the real aircraft nearly stalls during turns at low altitude. And I'm not using the FMGS calculated speed: I use an external calculator

However let's wait for the SP to see if the issue is gone

[Cheyenne Chief Pilot 829]

Replicated at last! There seems to be quite some complexity involved in this issue and getting at the root cause(s) will probably not be easy. No promises, but now we are reading you loud 'n' clear ...

[Airbus339 129]

Glad you finally found it

[Michael_LOWW 4]

Thanks for your feedback, Oliver!