fmgc, the problem with SOPs is the adverse mindset (bias) which may come from the mantra of ‘stick to the SOP’ particularly where there are qualifications – the unless’s are forgotten.
From your example– “
single hydraulic failure and get a shorter landing distance than you would for no failure, for a given overweight landing” (#14); why is this so?
Would a pilot just take this information for granted, or think about it – look for the assumptions in the data. The latter requires a mental attitude that ‘The SOP’ may not be applicable to this situation. Abnormal operation may assume different risks, specific crew procedures, etc, (the unless’s); if the mind is already closed to this type of thinking because of the ‘follow SOPs mantra’ then safety may suffer.
Many accident investigations conclude that ‘crew failed to follow procedures’. This implies violation, but with closer examination of the circumstances, the crew may have incorrectly assessed the situation and thence used a different (but incorrect) SOP, or with a good situation awareness, mistakenly chosen an incorrect SOP (forgot the unless) – perhaps a bias from the ‘follow SOPs mantra’. Pilots need to understand both the situation and the assumptions in an SOP.
Further, from your example above; what if the crew follow the SOP and use the OLD data without thought or judgement, overlooking a vital caveat like – no distance margin assumed, require reverse, max brake, etc. Use of normal procedures (SOP) without adjustments required by any caveat may increase the risk of an overrun.
It will be interesting to hear an explanation of the difference in that data; please don’t leave it to guesswork
