skiesfull, crossunder, I had hoped that this thread would avoid focus on a specific accident, the quest is for a generic solution.
However, re handling; although improved handling skills will position a flight towards a safer (optimum) operating zone they do not guarantee avoiding an overrun. If the runway conditions have deteriorated from those which were expected then there still may be insufficient runway to stop.
The point of a pre landing decision is not to ensure that the aircraft can land accurately and stop in the distance available, it is to ensure that it can stop
safely within the distance. The additional margin allows in part, for unforeseen changes in the situation and some errors, – note a similar absence of an adequate safety margin in many overrun accidents e.g. Congonhas, Midway.
The danger in singling out handling skills is that ‘good’ landings may be completed in circumstances which have a higher level of risk than desired by the safety standards in our industry; this builds a false level of security (complacency), such that an encounter with the unexpected may suddenly result in no safety margin at all, i.e. handling skills do not prevent or mitigate a decision error. DM must be built on discipline, the maintenance of safety standards, and avoidance of complacency or inappropriate industry norms.
Decision making (DM) should include planning for the unexpected. In terms of landing distance some of the ‘unexpected’ is included in the scheduled performance, but not for example a change from wet to contaminated conditions. Crew training should include knowledge of what is and is not included in the landing distance margins – what are the assumptions (Refs; AIC and Managing T&E slide 6).
Also, DM in situations that include ill-determined runway conditions should consider the difference between wet and contaminated distances. It may not be necessarily to plan for a contaminated landing in most circumstances, but at least a crew should arm themselves with information so if they perceived that the runway condition had changed it enables a decision to change an earlier plan, i.e. knowing that you should be able to stop safely on a wet runway vs knowing that you will not stop on a contaminated runway. A similar point can be made about braking levels; in what circumstances do you change from medium to max (know before you go), i.e. SOPs are only ‘standard’ if the assumptions are met - what are the assumptions in SOPs (knowledge required - training).
The Captains landing (or not) might be debateable, but whichever view is taken it involves a decision; thus we have to determine what goes into that decision and how is it taught. In the ref below (crew procedures) the proposals might provide guidance for a Captain if he has the authority (flexibility) in the operation, if not this information could be in SOPs, which would simplify the decision, e.g. Cbs with 5nm of runway – Capts landing (or SFO landing with monitored approach procedures). Providing the advice is justifiable to an operator, it matters little what the advice is provided it triggers consideration and subsequent DM, thus it essential to provide ‘trigger’ advice to aid DM (SOPs or memory). However, we should be aware that guidance or SOPs, etc, cannot cover all eventualities or situations. For those rare occasions or unusual circumstances, operators require the flexibility enabled by human judgement, but with that comes a tendency for error – so DM guidance also has to provide error avoidance/mitigation; … what is that and how is it taught.
AIC 14/2006 Landing performance of large transport aeroplanes. Registration required (free); then PUBS / UK AIC / Pink
Managing Threats and Errors during approach and landing.
Error-tolerant Crew Procedures.