Heading eastbound over the Baltic Monday PM we heard several calls to ATC from crews on a shorthaul type, possibly 737-800's, demanding descent because of the OAT/SATs. Now I agree it certainly was tad parky
, it was down to around minus 70 celsius at FL 350 overhead Helsinki/ Saint Pete's, but from the discussion it sounded like there was an AFM SAT/OAT limitation triggering the concern, not fuel temp - was that the likely issue?
(FWIW I'm a dyed in the wool Long hauler, had fun and games because of the Fuel temp more than once but never seen a AFM OAT/SAT low temp limit for cruise, hence the question)