Kym an interesting analogy. Can you tell me where in Oz you have experienced a 100 knot headwind at FL260 and on the same track get a 50 knot tailwind at FL360? We regularly see wind changes during climb and descent but nothing of the magnitude you mention. I have never seen that over the past 17 years across quite a few countries (including Oz) so look forward to your answer on that one.
The 146 ceiling is 31,000ft, what is the ceiling of the 717?