climb gradiant - performance theory
Hello all,
So we all know how performance theory is based on obstacle clearance of 35' feet attained with V2 and then second segment is based on 2.4% climb gradiant , while the final segment based on 1.2% etc etc etc...
How about SIDs that require a certain climb gradiant to a certain altitude.... I've been told that we on what we call in the states 'transport category' airplanes cannot guarantee climb gradiants as they are prescribed on charts... [jepps] so my question is, how does a 747 leaving for a 13 hour flight facing a SID that asks you to notify ATC as soon as possible if you know you will not be able to make a certain altitude climb requirement knows that it will not be able to make that requirement?
and on the other side of the spectrum, how can we taking off everyday with our smaller sized planes can guarantee to ourselves that we meet climb gradients as prescribed on SIDs?
Thanks!
-downwindabeam