An inability to manage uncertainty
There is an increasing trend requiring definitions for aspects which historically have been judgements - within airmanship, normal activity.
The op acknowledges manufacturer’s advice re ‘suitable’; items which could be considered relevant to that aircraft, but without defining specific situations.
Similarly there are operators who do not define, do not constrain crews from choosing a suitable course of action based on their understanding of the situation, in ‘the circumstances’ at that time.
Conversely definitions confine thoughts, opposed to remaining open to an evolving situation. Individuals arguing that action would be legal, providing an excuse (get-out), particularly with an unwanted outcome. Definitions can distract from the need to reassess the situation and adjust. A form of SOP mindedness; having chosen a SOP, then the outcome is assumed to be assured.
Why is a ‘legal’ definition necessary; judgements should be based on safety; situations assessed by crew at the time - they are the local experts who should be trusted to do the right thing based on what they see, guided by training and experience.
The need for definition, (a legal perspective), could be a reflection of the industry’s high level of safety - events are rare but more complex with uncertain outcomes; thus the fear of not being able to manage the outcome as envisaged by regulation or procedure.
An inability to manage uncertainty.