Originally Posted by
safetypee
David, #2980,
Being positive, the aircraft will be fixed.
Training is not a fix, and that which will be required will be consequential to the technical solution.
The level or mix of software / hardware revision depends what has to be fixed and the regulatory requirements for the changes.
There are indications (rumours) that some authorities are reticent to agree changes until the exact nature of the accident are know. This is significant if no particular component or software configuration has been identified as ‘failing’. No bent or stuck AoA vane (NB possible accident damage); no specific computational failure.
There was considerable speculative debate on the software issue in previous Tech Log discussions, concluding with convincing arguments (for me) as to the possibility of a ‘glitch’ which could cause a failure, but not subsequently identifiable. Software fixes for such glitches are well known, but might involve major change to computational system architecture and even require triplex integrity.
Any lesser solution could be seen as a ‘wet blanket’, i.e. the exact nature of the problem is unknown, but it cannot happen again because of … ‘fix’ xyz. This approach is a debatable certification technique, although previously used, but perhaps not for such a catastrophic outcome.
Hardware changes beyond the AoA vanes, probably involve the trim system and ability to manually trim in all conditions. Regulatory views on this and wider ranging human behaviour vary, and as with a ‘wet blanket’ solution depend on judgement vice a hard, quantifiable requirement. e.g. the pilots’ contribution to identifying and control of system failures.
As a worst case backup, Boeing is presumably working hard on a permanent fix for the issues identified above, even though that may require extensive aircraft rework.
In the nearer term though, to get the aircraft back into service, there will be need for an interim solution, including perhaps more extensive pre flight monitoring or other operational constraints. Such constrained operations are a normal response to aircraft deficiencies.
What is unclear is whether the regulators have any such plan or willingness to even consider something less than a fully definitive fix.