"... monitoring of the standby ADI is considered by some as unnecessary. Good airmanship would suggest otherwise."
Whichever view is favoured, it is chosen with hindsight.
Where would a requirement to monitor the standby instruments come from?
Certification mandates that a difference between the main instruments must be identified by a comparator - the monitoring function. Also that the combined failure of the attitude display and comparator must be extremely remote; thus the crew could have confidence in an alert and be trained to respond when given. However due to a system discrepancy, design or failure, the alerting function in this accident was removed shortly after the IRS failure.
This aspect and related issues were discussed at
http://www.pprune.org/rumours-news/5...ml#post9606976 and onwards to the end of the thread.
Taking 'a crew should monitor' view, then the crew would be required to deduce a failure where the automatic function could not - compare that with AF447 ADC malfunction.
A danger of hindsight is that specific issues in rare, highly salient accidents, are chosen for urgent safety action, but may not actually achieve the expected improvement.
The CRJ accident report recommended more training, new calls; the effectiveness of which was discussed in the link above with reference to the startle effect - automatic reaction, limited ability for 'rational' thought, and possible repeating surprise. Also consider any effect of recent LoC training - immediate nose down change in response to any pitch up.
Similarly, in choosing the need to monitor the standby ADI; why not the standby ASI, Altimeter, etc. The hazard in this is increased workload, perhaps beyond what has been assumed by certification and operational training requirements, thus exposing the crew for new opportunities for error.
This is indicative of a highly reliable industry, where a rare highly visible accident demands the need for urgent safety reaction, but where the intervention may do more harm than resolve very difficult combinations of contributing factors; particularly where alternative action is available.
Systems reliability could be improved, or at least achieve that required by certification; again compare with AF447 - fix the pitots tubes, and in this accident - fix the monitoring system, also in the 737 at AMS - retrofit the latest standard of Rad Alt (self monitoring).
Also see the recent incident involving an unmonitored enhanced vision display and rad alt in a PC21 (
Investigation: AO-2016-064 - Synthetic vision display error involving Pilatus PC-12, VH-OWA, Meekatharra Airport, Western Australia, 18 June 2016).
The industry should not choose the easy option of human intervention, more training, procedures, or call outs as a solution for complex problems, particularly where the human can be the weakest link - especially in monitoring.
Why not improve the equipment - cost? Not necessarily so, modifying a few aircraft in comparison to training all pilots, and with less assurance that the crew will monitor vs the ability to react to an alert.
Willingness to improve safety?
Perhaps this dilemma is the new challenge for a highly reliable industry; but first do no harm.