Cannot help 'blue belly' with the 75/6, but it is common practice on the 737 to have the pumps on for the walk-round to check for leaks etc and rudder position. It then becomes a
practical matter of 'how long before next the walk-round' and 'how long before we do the cockpit prep' for the next sector as to whether they go off in the shut-down or stay on. EG - I suspect Ryanair don't bother to turn them off. I don't on t/rounds of less than 45 mins, when I'm normally out of the seat PDQ, with fuelling, finding the agent, checking my bag has not been off-loaded in bongo-bongo land and beating the next rain shower in mind.
