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A320/A321 IAE flex takeoff performance fall from sky


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having a thrust performance problem with A320/A321 pro IAE engines only. the cfm work well. this has happened with 5 flights in row IAE only. takeoff performance at different airports over the last week KSAN, KPHX, KLAX, KLAS and now KSFO today at 1pm KSFO to KSAN. it had a F79 suggested takeoff performance calculation based off perfromance calculator. 

 

at the time KSFO:

winds were 320/11

OAT was 60F

TOW was 135194

 

ATC assign me 01R takeoff

 

Perf calcs gave me :

Flaps 2 config

F79 for temp

V1: 149

VR: 150

V2: 156

 

The plane was off the end of runway almost in water and barely lifted off. i had to pull back at 137kts or else i end up in the drink. the plane was barely climbing and when i hit 800' than speed declined and stall warning occurs. had to manual toga and get up. 

 

this has happened 5 times in row A320iae or A321iae models only. has even happened at KPHX where runway is 10,000' long. happened at KLAX KLAS too. 

 

Is there a fix for this? why does this happen in IAE only ? need help please . 

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2 hours ago, airtahitinuiforever said:

Flaps 2 config

F79 for temp

 

Looks like a miscalculation issue:

 

From FCOM IAE Engines limitations:

 

TFLEX cannot be:

‐ Higher than TMAXFLEX, equal to ISA + 55 °C. <-----  no more ( 15 + 55 = 70°C ) 

‐ Lower than the flat temperature (TREF)

‐ Lower than the actual OAT.

 

and in this RWY and this Weight , for F2 takeoff  speeds will be around:

 

v1= 141

Vr= 141

V2= 143

TFLEX= 66

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ok thanks polo will try again and see. i use the apsoft airplane toolbox for xplane. have created a profile based off aerosoft data. when i inputed:

 

KSFO

01R

TOW-135194lbs

Clicked the Metar button (metar matched atis and matched ActiveSky)

Clicked Calculate

 

it gave me Config 2 F79 @ 1pm today with the above weather temps and winds. I just went to apsoft airplane toolbox no and inputed same info with the correct engines and it gave me now:

 

KSFO

01R

TOW-135194lbs

Hit metar 

hit calculated and now it said this:

 

Config 1+

TOGA

 

weird

 

 

 

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So maybe I spoke too soon . Just took off 3 min ago from KSAN. Same problem . What is goin on here with the IAE models ? This time I took off from Ksan and used different perf calculator. Used the Wabpro online .


ksan metar 5-10min ago : 69F winds 355/02 OAT 16c alt 3021. 
A320iae

Tow 140030 lbs 

runway 27 departure 
 

 

so using wabpro perf calc (last night I used Apsoft airplane toolbox)....it gave me these 2 calcs for 1+ & 2

 

flaps 1+ config 

flex 70C

v1-145

vr-145

v2-146

 

flaps 2 config (THIS IS WHAT I USED)

flex 70c

v1-141

vr-142

v2-146

 

i reached the end of runway only at 130kts and crashed . How can this happen 6-7 times now even on a runway that’s 10,000 ft like kphx. I’m not suffering from this on CFM model. This is 2 different calculators. The iae model A320/321 struggles to pickup speed . 
 

can some1 please help or advise 

 

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I have had this issue for months or maybe for a year (Only IAE engines)., . In fact I don´t fly the A320 buses....but I love the A330. My favourite ac of simulation. 

 

Best.

 

Miquel.

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I looked on forum and this has been addressed goin back to 2014. I have not read on any of the forum threads that there is or was a fix. Even when I’m taking off a320A321 IAE ; I look at the speed tape on PFD and it’s barely moving compared to cfm and obvious common sense looking out the window the plane struggling to pickup speed 

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  • Deputy Sheriffs

What are the values suggested by our FMS compared to your's? How does the Aircraft then fly?

That are the values for your KSAN departure by the TPC tool.
image.png
 

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  • 1 month later...

I also use airplane toolbox. It is DEAD wrong with IAE flex trust me. The other day it gave me for a MTOW A321 Flex of 69 on KBOS's 33L... I knew the airplane would overrun the runway. I wish it would be fixed!

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