Tony R
I agree; in fact I do long flights, 700nm+ and I carry various spares like a vac pump, plugs etc. These were bought from the usual (proper) U.S. mail order places like Aircraft Spruce, without an 8130-3 but as you say who cares when it is an emergency.
I have no problem with paying for servicing etc (50hr check at ~£500) and I do try to talk to engineers about various things. However it is a fact that most engineers I know don't fly for themselves because they have little money, or have no interest in flying, or both. The exceptions are notable and I would always prefer those to service my plane (which is on a Transport CofA so I am fairly well stuffed on DIY).
What I don't like is when a LAME chews up half the screws with a power screwdriver and I have to buy a screw kit from the USA for $50 to replace them. I feel like doing a LAME training course
Incidentally I don't like the way most UK flying mags waffle generally about maintenance without specifying what the owner can actually do. They seem to assume the plane is either on a Permit or a Private CofA. I suppose anybody who is an owner would know the difference but perhaps not??
As regards someone's comment that the engineer said "yes I know about that defect" the overwhelming chance is that he does know about it, unofficially, but has been explicitly told by the owner (usually a school) to not spend money on it. Training planes in particular tend to be maintained on a strictly "need to fix" basis and the workshops are well used to working that way. Fixing a plane to a "perfect" standard costs a whole lot more money, and if one applied that policy to avionics it would get 10x worse.