Thanks for your sensible comments regarding my post (a rarity for Pprune?!). I do a fair bit of flying as SLF and I am a trained aircraft engineer but it was a long time ago. I worry that I might be in a situation where I think that something isn't quite right and then it's 'Should I mention it or not?'. I appreciate that we've had threads on this and it is a bit off-thread (sorry mods), but it is a worry.