GE fuel routing
I've only flown one 74 with Prat power, god bless Miss Piggy. But, as I recall with GE's the fuel passes through a fuel oil heat exchanger. If the fuel/oil exchange shows low flow or clogged only then is heat applied to clear the ice blockage. A note in the handbook, basically said continue and monitor. I don't know if I ever saw this development in fifteen year of 200/300 operations.
Even several year ago, when FL temperatures across central/eastern Europe were extremely low, the whale has a hot wing. Don't think I've ever seen the fuel temperature ever approach with in plus ten of the fuel freeze point.
The procedure was always to speed up, maybe M.86 or a bit more or lower FL or both.
It would be interesting to hear some comments form operators of the newer higher out put engines from both Prat and GE on how the systems operate in real life.