Acceleration altitudes

[vilas]

A320 minimum and maximum acceleration altitudes.
In flight operations web conference 2009 FAQ take off charts acceleration altitudes, Airbus explained minimum acceleration altitude as the maximum of the minimum acceleration altitude values on a global set of points and maximum acceleration altitude as the minimum of the max acc. altitude values on global set of points.
I am unable to understand the concept and terminology. Can anyone give a better explanation of this? Thanks
You can access it from below:
dream-air.ru/new/pilotam/WebConference-01-RTOLW_FAQ_takeoff.ppt

[Goldenrivett]

Hi vilas,

Just read the relevant slides briefly, but it looks like for simplicity they have published a min and max AA for each page of data.

Min AA will ensure that for all the weights, temps & winds on the page, the Aircraft will clear all the considered obstacles during the level acceleration and transition to clean wing climb.

Like wise the Max AA will ensure the engines are able to be set to MCT before the time limit for all weights etc.

In the case where the "simplified" min AA exceeds the "simplified" Max AA, then you'd have to look at a more detailed analysis on the "specific chart"

[vilas]

Goldenrivett
Thanks, for maximum altitude was easy to understand since it is time related will vary with weight and temperature but minimum being 400 for all was confusing. Also the use of word global. Airbus uses this word often. It has been used for speed protection as global speed protection. May be in computer language.

[FlightDetent]

Hello gentleman,


I believe the min ACC ALT of 400 ft is just a regulatory requirement.


The "global set of points" probably is opposed to "single point calculation". The latter term is being frequently used in PPM for PEP/LPC calculation, meaning the values and their extremes / limits are valid for one initial input data [as in one box from an RTOW chart].


The V speeds limiting values as well as the ACC ALT values shown on the bottom of the chart need to be valid for any possible entry and all results from the table above, so naturally they are the most conservative ones. I think Thierry is trying to say that the dislayed limits are valid for the full table in general - "wide range of possible calculations"


That's the best I can make of it. Sorry for the broken English on my side.