Does the 777 fuel tank contain sensors for ice as well as water?
Each tank has a water sensor. This works by sending a signal down through the fuel which is reflected off the tank bottom surface. The time the signal takes to make the journey is measured. If there is water or ice in the tank the signal will be reflected from the fuel/water (or ice) interface. The resultant shorter signal journey will trigger the water in fuel maint message. So yes the water sensing system will react to ice as well as water.
Originally Posted by Rainboe
instant flaps- they could take 20 seconds whilst sucking your elevator control dry of all power!
But retracting the flaps from 30 to 25 will only take a couple of seconds, and they had all hydraulics working so no loss of hyd pressure.