aeronaught321, #2730, I agree with your interpretation of the Reuter’s article linked by
blind pew, #2729. This should be read by everyone contributing to this thread.
https://uk.reuters.com/article/us-et...-idUKKCN1RA0DP
The point being made relates to an existing issue discussed in the thread
Boeing advice on "aerodynamically relieving airloads" using manual stabilizer trim which refers to the separate problem of ‘runaway’ trim.
However, this is very relevant to the accident discussion because of the accumulated incremental trim change due to MCAS malfunction can result in the same trim condition.
The difficulties in flying the aircraft in a nose-down mis-trim situation are identified in the Reuter’s article (pilot quotes). Further to this, in a situation where MCAS involves incorrect high AoA value, the inferred stall condition appears to change the pitch feel, with further increase in nose-down control forces, i.e. it is possible - even most probable based on the Lion accident, that the aircraft can reach a condition from which it is physically unrecoverable.
If the Boeing ‘MCAS’ mods sufficiently restrict the trim movement then such high forces should not be encountered, but in some circumstances (failed high AoA) the feel system additive could still apply.
EASA, other regulators, and FAA could revisit the runaway trim certification to check if any of the 737 Max physical, aerodynamic, or engineering changes (cable friction), change the level of out of trim force and thus affect the ability to recover the aircraft, or even if the difficult, unusual manoeuvre required (tech log) is viable based on modern pilot experience, sufficiently trainable, and can be identified in time.