B777 eng inop NNC: flaps 30 or 20 with G/A gradient?
Hi everyone,
In the B777 Eng Fail (or shutdown) NNC, at some point the C/L asks to choose between Flaps 20 or Flaps 30 (if perf. permits) for landing.
The obvious answer is: Choose Flaps 30, and if needed for example for G/A climb gradient, use Flaps 20 (with G/A flaps 5).
So I just had a simulator with a diversion to BGSF, where the approach, on RWY 09 requests a climb gradient (not an ATC climb gradient) of 5%.
My question is: How do I check if I can land using flaps 20?
-If I do a landing distance calculation with no failure in the OPT (or using the Performance dispatch of the FCOM), I can check that, landing flaps 30 with a Flaps 20 G/A, the plane will be able to follow a specified climb gradient when going around with one engine failed. Of course, if this is OK flaps 30, it will be ok flaps 20.
-But what should I do if the OPT tells me that the plane won't sustain a 5% climb gradient with flaps 30/GA flaps 20? How do I check if the performance will permit to get a 5% climb gradient (or any other CLB gradient) with the option to use Flaps 20 / GA Flaps 5?
Because a G/A with flaps 5 has a better climb gradient than one with flaps 20 doesn't mean that it will be a sufficient climb gradient.
Thanks in advance for your help!