Nor am I comfortable with this focusing on one “error”.
True, there is always more to these cases than a single mistake.
I’m not sure one can say for certain that the mistake would have been made anyway. From what little I know of the case, the MoD regs, if implemented properly, would have been sufficient.
I only refer to the safety case error here. You can't say or imply this error would be removed if e.g. you had a MAA etc. Some here seem to be doing just that.
The "error" by one person in the Nimrod IPT is a very minor issue here.
As you say above, its only one of several issues - lets not forget that the safety case issue was only a review of the design, the 'flaw' was put in the design many years earlier.
I don't think you could lay this mistake at the door of one person in the IPT anyway - the review process would involve many, and I'd have expected at least one BAES engineer, + someone from BAES QA, + one Independant Safety engineer to have been involved all areas, i.e. including assessing the area under debate. Having an operator involved may have helped pick up the issue - this could be a lesson learned. Not sure how you'll get an operator interested in wading through pages of fault trees etc., but thats another issue....