Zitat

Die Daten dafür werden einer Chart für die betreffende Landebahn entnommen.

Zitat

Derated Takeoff
Tero Partanen (the Finnish Flash) explains how to decifer the performance
table(s) included in the Perf Manuals folder, offering this
example (your result(s) may vary):
Runway 22R: 3600m 11,000 feet
Temperature: 4°C
QNH: 1003
Wind: 260/12 (10 kt headwind)
First, calculate the MTOM (Maximum Takeoff Mass). This will determine
whether we can derate the takeoff.
In the 11,000ft FLAP5 table there are 3° and 5° rows, which both
indicate 197.4t for MTOM. As the QNH is 1003, it’s 10mb BELOW
1013, and thus we subtract 10 x 100kg from MTOM to get the
regulated weight of 196.4t. However, the max structural mass
is 185068 kg, so that will be limiting. Finally, we see if our TOM
(142.6t) is below that (and it clearly is), so we ARE allowed to
reduce thrust.
Next, we get the assumed temperature. First, we need the assumed
TOM, which we can get from the actual TOM (142.6t) with
the QNH correction. Now we apply the correction in a reverse
sense and add that 1000kg to get the assumed TOM of 143.6t.
Now we look at the table again, and see what temp is there for
that ATOM. As the weights table ends at 146.4t, which means that
you can use the maximum derate for takeoff, which according to
the table is 61°C.
NOTE The calculation of the reduced thrust temperature involves
variables such as runway length, slope, altitude, and departure path
obstacles. The use of reduced thrust settings is at the pilot’s discretion.
Eric Ernst offers this tip from the 767 Operating Manual: As a
quick guide, for long runways (>10,000 feet) use a value of 54° C.
For shorter runways, use a value between current airport temperature
and 54° C. The lower the temperature, the lower the de-rated thrust.