Engine wash
I don't see the point making the engine wash at both engine idle, you lose the alternators at low RPM and you have to switch back to flight for 5 minutes drying time anyway.
For the hydro-alternator, it has to be tested before the first flight of the day and specially for offshore flight. It's a No Go. Don't expect to last on the battery more than 20 minutes in case of losing both TRU's, which was not unusual in hot countries before the modification of the exhaust.