Spitoon
Marvo has just said
Whilst I was not the pilot flying I am sure my respected colleague was aware of the aircraft mode selected...
Sorry, but a mistake is a mistake, and if he had selected the wrong mode in error that's fair enough - but this is not the case here (it seems) and not knowing the implications of a selection when flying an aircraft is not really good enough.
Your quote
...And that we always know everything about the equipment we use....
is slightly out of context - it's not a case of knowing the engineering behind the equipment, it's about knowing what the equipment does in real terms when you use it!
Unless things have changed since I flew for a living, most pilots will have to learn and understand in some depth about the systems they are using, including down to the nitty gritty of studying and being able to put into layman's terms, the circuit diagrams of major systems etc.
Not knowing, or possibly disregarding the fact, that certain mode selections means an inability to comply with an instruction is not good enough as Tarnish, a current professional aircrew poster, has pointed out above.