First @piperboy84 my respect for posting your mistake!
It makes me feel better whenever I see mistakes still be discussed openly.
You did not do your math and that is something we all are able to learn from and alter.
Did you turn that 15 degrees before talking to Granada? Nothing wrong to radio "unable, turn heading x to keep clear of terrain", but your flight should be executed in a way to be able to get a clearance in controlled airspace first or in case of urgency, announce prior to, or at really latest at turning. Turn first and than radio sounds a little like urgency turned emergency to me. In that case fly the aircraft first is absolutely correct, but should be subject for critical self review, what you do by also posting here, fine!
What kind of aircraft did you fly? For BA or airliner it is sometimes not easy to get the weight correct and if on the edge, you are easily over calculated weight special when getting into hotter then expected air layers. So, even if you did your math according to company rules, you may encounter insufficient climb performance.
Trying not be be rude, if this was in a GA aircraft, you derived first from your flight path and than called, I see why they were upset. In that case I would conclude for the lessons to learn: do your math, think ahead in flight, request or call early and prior to action.
Last edited by Fly4Business; 25th Mar 2016 at 10:10.