A Pommie
Thanks for your definitive reply. I couldn't believe that a manufacturer would install such a deadly one way street.
Now for the hard bit,how do I tell the much respected but volatile FI and persuade him to try it,even on the ground,as in his present mindset we'll need to get an engineer from 40 miles away if I pull the dreaded knob ?
I could promise to forego my lesson and pick up the engineer at my cost if we're wrong.
I'd better not have the slightest hesitation or omission in performing his 'flowline PFL check ' in future.
Do you think the myth was started after someone did a FL when they failed to detect and correct the problem in their pre FL checks, mags, fuel pump, carb heat, tank selector/cutoff etc.
atceng