Originally Posted by PJ2
Also, there may be different sample rates, varying from once per second to eight times per second.
The Taipei Sungshan incident report states in the appendix (p146, response from Airbus) that the brake pressure is only sampled once every 4 seconds.
I'm not sure about the recorder type of this particular aircraft, but this seems a low rate, considering that anti-skid will modulate brake pressure much faster than can be recorded.
(Although Concorde was a much older aircraft, I remember from my analysis of the Concorde accident, that its FDR sampled each engine's parameters only once every 4 seconds in a round-robin fashion, which made exact engine behaviour (e. g. surging) hard to detect)
Originally Posted by Dream Land
wasn't it about 30 seconds after touchdown when the NFP announced "no spoilers" or something similar?
Looking at that transcript again, let's assume MLG touchdown is two seconds after "twenty" call (some A320 pilot said the touchdown noise in the cockpit is NG touchdown), then we have:
18:48:21 "twenty"
18:48:23 MLG touchdown
[...]
18:48:26.3 NG touchdown
[...]
18:48:29.6 HOT-2 "Spoilers Nothing"
That's 6.6 seconds after (assumed) MLG touchdown, or 3.3 seconds after NG touchdown, either way a long shot from 30 seconds.
A normal landing would have something like (give or take):
0s FWC: "twenty"
2s MLG touchdown
6s PM: "ground spoilers"
9s PM: "reverse, decel"
(These callouts can be heard near the end of
this video, start around 4:40.)