Interesting - and never ending - discussion, this one. I guess any firm conclusion is way ahead....
But still, just some small additional comments to comments:
..upper age limit for instructor examiners..
Not in JAR-FCL. As stated earlier, the
only age limit in FCL is for Commercial Air Transport, i.e. the transport of passengers, goods and/or post for renumeration, normally indicating an AOC organisation. (Not counting any evt. national regulations/variants)
..taking a 2400hr Lycoming across..
Weelll.... the only engine hiccups I've encountered in 25 yrs have been in relatively new/reconditioned engines, not properly 'debugged' yet. Every engine straight out of heavy maintenance is a potential for... you know. No disrespect to good friends in maintenance, but I do have a few nice tools in my collection - retrieved from engine bays after maintenance..
.. and a few hairy stories..
Engines apart, (pun intended, and to keep this going in a good humor) e.g reversely coupled ailerons wouldn't just 'show up' after several hours flying, would they?
(Covec: no mention. Just teach them good airmanship)
cheers,
redbar1