Hi guys!
Possible UK regulations aside. Anyone with a UK reference BTW?
My understanding is that the mentioned 2.1% is an aircraft certification criterion i.a.w. EASA CS-25.
Whilst operationally we should always use 2.5% as this provides us with the required obstacle clearance i.a.w. the procedure design gradient of PANS-OPS unless otherwise stated.
Correct me if I am wrong.
Regards