EdSet
The report says the fuel system is not ALARP. The latest copy of Defence Standards defines ALARP as:
As Low As Reasonably Practicable. A risk is ALARP when it has been
demonstrated that the cost of any further Risk Reduction, where the
cost includes the loss of defence capability as well as financial or other
resource costs, is grossly disproportionate to the benefit obtained from
that Risk Reduction.
This seems to include a good measure of wriggle room for an aircraft or its fuel system to be declared ALARP if as with Nimrod it has a desperately needed capability and yet the report specifically says that the fuel system - not just the air-to-air refuelling system, the fuel system - is not ALARP.
The latest copy of defence standards defines safe as:
Risk has been demonstrated to have been reduced to a level that is
ALARP and broadly acceptable or tolerable, and relevant prescriptive
safety requirements have been met, for a system in a given application
in a given operating environment.
So ALARP seems to be the one factor that has to be present.
http://www.dstan.mod.uk/data/00/056/01000400.pdf
