Location of fuel temperature probe (Boeing airplanes) is in the "coldest" tank.
Coldest (sorry, I use that designation) by its location, and absence of heat exchangers.
Such as hydraulic system heat exchanger/coolers.
And obviously, a CWT is always much warmer...
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If fuel temperature probe inoperative, assume it is same as TAT or RAT.
In 747, the selector reads fuel in tank nš 1, or at
each engine...
Fuel gets cold and you worry for 7 hrs cruise at 410... learn PanAm's technique.
On long flights, they kept fuel residual in the 747 CWT.
I recall F/Es generally keeping up to 5 tonnes of "warm fuel" in the CWT.
If need be, or at end of cruise, that fuel was transferred to "cold tanks".
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If your Boeing aircraft type cannot do tank to tank transfer, you still can do CWT fuel to engine.
Happy contrails