Quote from
HazelNuts39:
"I’m pleased someone is interested in my little exercise.
... with some help from BOAC and PJ2."
You are too modest... I did wonder. But may I suggest it may be advisable to provide an attribution, in case someone assumes it is extracted from an official report?
Quote:
"The DFDR traces in the ATSB report include AoA, but the scale chosen to show the ‘spikes’ is too small to read a real AoA value."
I see the problem, but would it still be worth superimposing the official AoA trace on your graph, for comparison purposes: uncorrected
– and perhaps also corrected
– by the
Prandtl-Glauert "rule"?
Not having read the QF72 report in any detail, must admit I do not know if wind and/or vertical air-currents were a factor. In relation to AF447, however, there is every reason to suspect that horizontal and/or vertical gusts may have at least contributed to the aircraft departure.
Quote:
"In this case: it is assumed that the airmass does not move vertically: sin(fpa)=vsi/TAS "
In our earlier discussions, I think I was able to establish in #
552/Mar23rd
– if only qualitatively
– that even a steady movement of the airmass (vertically and/or horizontally) leads to an error in the assumption that " alpha = pitch - fpa "
. As for gusts, they are another matter.
Nevertheless, subject to the points above, your graph seems to be a very useful exercise – thanks.
And thank you, CONF iture, for the official graph of AoA for the XL Airways accident.
Chris