Originally Posted by john_tullamarine
chornedsnorkack
I'm sure there is something subtle in your handle although my lack of imagination causes it to remain elusive in the recesses of my tiny brain ..
A reference to Harry Potter series.
Originally Posted by john_tullamarine
V1 most certainly is NOT arbitrary (although one could/can schedule an acceptable V1 range for the day if one so wished and data were available).
WAT has naught to do with it as WAT relates solely to minimum climb performance standards as prescribed in the relevant aircraft Design Standard.
Surely the climb performance and Weight, Altitude, Temperature are vitally important to V1 choice? Because the minimum of V1 range seems to depend on the ability to perform Accelerate-Go... calling V1 early and happening to get below the lower end of V1 range (unaware where the lower end of the range is because not wishing to or having the data to find out) could result in attempting a takeoff despite lacking the ability to fly and crashing at a high speed at or beyond the runway end instead of aborting and crashing at a low speed runway overrun?
Originally Posted by john_tullamarine
What you are saying is fine and can be summarised very simply .. certification performance data is artificial in that it establishes lines in the sand for very well defined boundary test conditions. If the line pilot wants to reproduce the data, he needs to have the same boundary conditions and that prerequisite, generally, is unachieveable. It follows that the line pilot probably is going to be able to go close (to a greater or lesser extent) but not quite get to the mark .. and, if achieving the mark is important (rocks at the end of the runway ?), then maybe that difficulty needs to be factored into the operational decision making equation along the way somewhere ... ?
Maybe it could be said differently... the certified Flight Envelope is an envelope of sharp lines and corners drawn across a picture of shades of gray.
It is not true that the interior of the Flight Envelope is all white and safe. There is plenty of gray everywhere, and there are corners which actually are rather dark gray. On the other hand, many of the lines are drawn right across rather light gray.
So, a line pilot must first be aware of where exactly the black and dark grey exist. Second, the pilot must not assume that the interior of the envelope is white throughout, or that it is uniformly light grey. Third, the pilot should be aware of the lines across light gray.