Have I missed the point that you were trying to make?
Probably. However, that would follow from my having a certification background in addition to an operational history
the question seems to be perfectly valid.
.. except for its attempt to relate certification data to a certification-irrelevant consideration. Had the question simply said to use this speed or that, or had provided, for example, a climb performance chart from which the candidate were to extract relevant data, all would have been fine. Tying the question into a very particular certification set of data creates a problem, however.
First Off, CAO 20.7.4 says:
One needs to be a little circumspect with the 20.7 operational Orders. The P-chart is one of the old DCA Civil Mk II (if my memory cells serve me correctly - you, I have no doubt, would remember having played with many of these in your younger days) charts. While I haven't bothered, as yet, to see if I can identify the origin of the Echo, the P-charts for the Echo, without any doubt, would have been lifted from a convenient Industry flight manual by the then examiner in the same way that the Alpha loading system (originally designed by Norm Overmeyer and then modified a tad by Bruce Clissold at the examiner's request) was lifted (almost certainly) from a Turbo Lance Civil Mk I flight manual - its design predates the general introduction of the GAMA Spec 1 POH format manuals which came into vogue, as I recall, in the early 80s (can't have been much earlier as the original GAMA document only dates to 1975).
The light aircraft P-charts were produced to satisfy the requirements of ANO (then CAO) 101.22, which was the relevant certification document. The 20.7 operational series were, in respect of certification requirements, an (often, but not always, correct) recasting/copying of the certification requirement. However, the cited Order paragraph is from the 101.22 words. As an aside, I often wonder how the 20.7.4 requirements are imposed these days, given rubber stamp certification of foreign NAA POH documents
Note: The gradient of 6% is an air gradient @ TOSS, not a ground gradient.
All certification WAT limits are for nil wind. The operational requirements then impose whatever pilot-related stuff needs to be applied.
Referring to the Echo Chart - Fig 12 below, the TOSS at 2800 kg is 95.5 kts-IAS (give or take)
I have no problem using whatever speed, only tying a certification-irrelevant question to a certification-specific set of data when, to do so, sets the new chums up for significant negative learning. The question should have nominated whatever speed by alternative means.
To achieve a 3.2% ground gradient:
Does it not give you any concern that to achieve the cited gradient would require the takeoff power to be reduced by a significant margin ? This is the basis of my concern as the certification standards proscribe any reduction in power setting by the pilot during the takeoff manoeuvre. To have such a question sets the new chum up for negative learning.
In reality, you would climb out at Vx or Vy or faster, not TOSS.
If one has an interest in achieving the POH/AFM distance data, then it is appropriate to use Vtoss only. To adopt a higher speed involves a significant distance penalty. Vx/Vy are speeds which might be appropriate following the initial takeoff phase of the operation. This point is an extremely important factor for the new chums to get into their thinking very clearly (notwithstanding that more experienced pilots, who have the technical skills to run appropriate sums on the fly, might do something a little different in appropriate circumstances).
I would have to say that SJM is correct on this one.
If the point is that the calculation is fine, I'm comfortable. However, not with the purported linking of a certification dataset with a calculation that has absolutely naught to do with the certification manoeuvre.
Should my words not convince you then we shall have to continue to disagree.
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