Approach Climb Configuration
For my airline, the B757 does a OEI approach at flaps 20. In the event of a OEI missed approach, the flaps are moved to 5.
Looking at FAR 25, it seems as if the Approach Climb gradient of 2.1 is at Flaps 20 since this is the approach configuration, but it is not exactly specific.
So, is the 2.1% climb gradient "guaranteed" at flaps 5 or 20?