Jwscud, I don’t know of any particular research re the effect of
technology on reducing the accident rate (N.B. not autoflight). Of the few documents which profess trends most restrict their views to one particular subject, which may or may not be correlated with other contributors.
The difficulties in multivariable analysis are often reflected in accident reports which state a wide range of recommendations covering a raft of issues, but without individual prioritisation.
It’s difficult to visualise complex interactions; NASA has attempted this in the previous referenced
Aircraft Loss of Control Causal Factors and Mitigation Challenges; however the analysis is based on the outcome and not the contribution of technology or safety activity.
An overriding problem in this is how safety is perceived - predominantly by accidents, failures; whereas the objective is to eradicate accidents – no failures, which if achieved might represent ‘no safety’; as there shouldn’t be anything to measure. Hollnagel discusses this in many documents on Resilience, Safety 1 and Safety 2.
Airbus’s refreshingly different analysis of
Commercial Aircraft Accidents 1958-2013 compares categories of accidents vs the advancing technical generations of aircraft.
Thus the reduction in CFIT and LoC accidents might be related to TAWS and Envelope Protection, whilst with little technical activity Runway Excursions remain high (page 15).
However there are inconsistencies; even with the later implementation of TAWS, why does second generation CFIT rate remain high (page 16). This quandary might be more marked by the apparent increasing LoC and Runway Excursion in second generation aircraft which might be as expected by a ‘U’ shaped distribution with age and lack of technical intervention; older aircraft, operating environment, engineering standards, etc. (pages 17-18).
This might indicate that there are greater non-technical issues involved.
I can see the attraction of including CRM in the list, but there may be greater safety value in considering the wider social/operational environment (discussed in previous posts) which may have better capability to influence human behaviour, i.e. in creating the situation which the human has to assess, understand, and manage.
Alternatively, both improved technical and 'non CRM' human input can create safety (the opposite measure of safety as in alf’s designing an accident) by shaping the operational environment. This has some synergy with Engineering Resilience – to build something, but this too involves human activity much earlier in the process – regulation, training, normal behaviour; cf previous hypothetical accident. CRM for regulators and managers; and technology to aid, shape, and guide human behaviour: - decison aiding, not decison making.