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Boeingdriver999
14th Jan 2023, 17:57
Hi all,

Where can I find decent Airbus/EASA documentation about the difference between assumed/Flex ASDA and the reality of ASDA?

There was a percentage reduction in ASDA that was calculable before but I can't find it anywhere and people keep thinking high Flex temps = low stop margins. But the fact is that those ASDAs are based on the high air temps (ie ISA + 30-65) and not representative of the real situation.

Thanks,

BD

ScepticalOptomist
15th Jan 2023, 02:52
I assume the Airbus method would still be trying to balance the field length using reduced thrust. By itís very nature the stop margin would be reduced - intentionally.

Qwark
15th Jan 2023, 03:38
Hi all,

Where can I find decent Airbus/EASA documentation about the difference between assumed/Flex ASDA and the reality of ASDA?

There was a percentage reduction in ASDA that was calculable before but I can't find it anywhere and people keep thinking high Flex temps = low stop margins. But the fact is that those ASDAs are based on the high air temps (ie ISA + 30-65) and not representative of the real situation.

Thanks,

BD

There is a document you can find online called “take off safety training aid” which comes from Airbus. It’s not policy just supporting material. It describes the additional margin over and above what is display in your Flysmart result.

Alex Whittingham
15th Jan 2023, 12:21
Thank you Quark , I have found an Airbus document from 2001 that will be very useful. Accepting that this is 20 years old, and that even then they could calculate the delta, does anyone know if the current Airbus EFB software takes account of the lower-than-anticipated TAS on a Flex take-off to optimise TOM? Same question for the current batch of RTOWs.

sonicbum
15th Jan 2023, 13:14
Thank you Quark , I have found an Airbus document from 2001 that will be very useful. Accepting that this is 20 years old, and that even then they could calculate the delta, does anyone know if the current Airbus EFB software takes account of the lower-than-anticipated TAS on a Flex take-off to optimise TOM? Same question for the current batch of RTOWs.

All You can Flex ;-) (https://www.pprune.org/tech-log/617257-stop-margin-based-oat-flex-temp.html)

BoeingDriver99
15th Jan 2023, 13:41
Exxccceeelllleentt!!!