Originally Posted by
mustafagander
As I recall the JT3D engines, we used to apply fuel heat at a regular time (30 minutes?) for 1 minute when the #1M tank temp was below a given temp. Tank #1M was the only one with a temp sensor. We also used to apply 1 minute of fuel heat if the fuel icing light illuminated for any engine.
I apologise if I've got it all mixed up, I last flew B707 as FEO in 1977.
I believe you are correct regarding the manual application of fuel heat. The trick was to not get distracted and leave it on for say ten minutes. The comon solution was to take the amber fuel icing cap off and hold it in your hand so as to remember what was going on.