ORJ: You seem to have a good understanding of the topic. I am somewhat involved with implementation and training of our EFB Performance Software and little more understanding of Performance Class A came as a necessity.
My advice would be to carefully listen to all what OS and j_t share with us and proceed with great caution and utmost suspicion if anybody tells you things differently. Next best thing is to look up their posts from the forum archive.
For some self-study, look up Airbus publication
Getting to Grips with Aircraft Performance; as far as I know it had not been updated recently so make sure the quoted regulations apply to your operational environment.
I am very far from being a performance engineer of any sort, but here are some of the key points I discovered. At the same time, I am not convinced these are understood well among day-to-day line pilot community.
- a) Why generic FCOM RTOW charts with no embedded obstacle data are close to useless,
- b) Why RTOW charts with obstacle data but no description of lateral track are close to useless
- c) Why deviating from the OEI prescribed lateral track puts you in peril; that includes cleaning up before starting a turn where the turn is prescribed upon reaching EO ACC ALT
- d) Why EFPs that do not end in a holding fix fail to address some fundamental issues
- e) Why MEA/MORA between ADEP and TKOF ALTN needs to be evaluated as well
- f) Why Eng Failure at top of the V1 range is not the most limiting ASDA scenario
- g) Why using wet performance figures instead of dry reduces your performance margins and, if the runway is damp, is illegal
- h) Why AST/FLEX takeoff is inherently safer
- i) Why AST/FLEX takeoff stop margin displayed as a result of most calculations has very little relevance to actual achieved ASD
- j) Why fixed derate may provide more payload while AST/FLEX does not
- k) Why using full thrust in OEI could be deadly if you had calculated fixed derate
- l) Why, in weird cases, intersection departures may yield better payload / higher AST/FLEX
- m) Why rolling take-offs are mostly ok
- n) Why line-up distance allowance is not a laughing matter
- o) Why the amount AIP provided obstacle data is grossly insufficient for proper TKOF performance calculations in places where terrain is a factor.
You see, I am still only half way down the alphabet
Sorry for such a large thread drift, but I think your original question had been successfully explained.
Sincerely,
FD (the un-real)