Thats the crux of my question following an eng. shut down you are directed to land using flap 20 or performance permitting flap 30
Yes, but if you were planning on landing overweight
as well then you'd go into that (unannunciated) checklist which would put you back to F20.
in the over weight scenario completing the O/W checklist does not permit Flap 30 single engine..... but what happens if you need to carry out a flap 30 landing?
Do you over ride the check list?
If the 13kts increase in Vref is going to make the difference between stopping on the tarmac and going cross-country, then I think you've answered your own question. To be put in this position your chosen runway must be very short and/or heavily contaminated... To be landing overweight on a poxy little strip you must have some sort of nasty time-critical emergency on the go as well: it's not your day - make up your own rules!
