VS previously steady at 600ft/min, deceases to 400 then increase to 900-1100ft/min, at the same time as oscillating pitch and roll, generally towards nose up, then nose down. Comparing this with the previous incident one might deduce a rapid onset downdraught, even a micro burst windshear.
The change in average VS, from ~700 fpm to ~1000 fpm, coincides exactly with the PF going to "manual control" at 550 feet. As does the consequent steepening of the glide path (Figures 2 & 8) - which then remains more or less constant at the new angle until end of chart. Looks to me more like pilot input (intentional or unintentional). Microbursts usually result in
accelerating downward VS, rather than a single change from one steady descent rate to another.
Note the steepening curve in your own wind-shear example.
(The same for the onset of less stable flight in roll and such - face it, autopilots are often steadier than human hands.
)
In a wind-shear event, I'd expect some germaine CVR comments (based on what usually is heard in such events) - along the lines of "WTF!!? POWER POWER! Pull the nose up!"
But a full second-by-second CVR transcript is exactly one of those elements missing from this prelim report.
Always remember that the scientific approach to an investigation is not to ask "What evidence here is consistent with wind-shear (or other theory)?" - but "What evidence here is absolutely inconsistent with anything
except wind-shear?"
I do hope that the final report will mention whether the crew was actually visual or not at the MDA. Many here are assuming that just because the PF mentioned runway not in sight at 900 ft, he was also not visual at the MDA. There is no mention of this in the report.
Exactly. Absence of evidence is not evidence of absence. We just don't know - yet.