Originally Posted by
slip and turn
At some stage afterward, FR9431 also turned left and diverted to Shannon at FL170 although I only heard the heading clearance of 250, not the level. The stray 267kts ADS-B plot for FR9431 also carried an altitude of 19800. The next plot I have seen was 297kts at 19275. EI933 had been further ordered to "Climb FL210" which was acknowledged, so I think we might conclude that EI433 at that time was lower than FL210 and had not in fact levelled at FL210 until ordered to climb back up there.
Meantime FR9431 may still have been as high as 19800. If that is the case maybe that's where the controller's eye view of an 800 feet separation comes in.
Yes, a more detailed look at the FR24 data (subject to the usual caveats) doesn't support the assertion that the Aer Lingus levelled off at FL210, instead suggesting that it was still descending at around 1000 fpm at that point. There aren't enough data points to establish how much lower he got before being requested to climb back to FL210, but the minimum vertical separation from the Ryanair was clearly significantly less than the quoted 1800'.
If Simon has more granular data for the 20 seconds or so where the (potential) conflict existed, perhaps he could share it with us in support of his statement that there was no loss of separation.