Airbus Flex Temp and TMax

[Pilotas]

hi there.
Calculating flex temp manually by quick reference tables Im a bit confused.
here is an example.
TORA 3000m, TOW 67.2. All previous corrections and calculations have been made. according the table Im getting 61 degrees of flex temp. but TMax is 53 deg. Means flex cannot be more than 53. next step is applying A/C bleed correction (or anti ice). 7 degrees has to be subtracted from Flex temp. the question is: should I apply the correction to
a) TMax 53 (53-7=46). 46 is the final flex temp
b) 61 (61-7=54)? 54 is still greater than Tmax so 53 is the final flex temp.



thanks in advance

[safelife]

Tmax is only for actual OAT that high! You can flex higher than that.

[vilas]

TMAX and TFLEX MAX are different things. T MAX is OAT for take off while TFLEX MAX is where maximum thrust reduction allowed by regulation is reached.

[Pilotas]

thank you very much. Now its clear where my mistake was.

[Pilotas]

one more thing.

does it mean if taking off with MTOW flex temp cannot be used?

[vilas]

It is self explanatory.

[Anvaldra]

Why not if conditions permit? If temperature requirements are kept - go ahead with MSTOW

[vilas]

Pilotas


In the example given in the manual the first two steps are as follows:
1. Determine the maximum permissible takeoff weight.
2. The actual weight being lower than the maximum one, flexible takeoff is possible.


So if that is not the case then there is no question of why not? You just do TOGA.