The cetane index is the only grey area which would required the JET-A/JET-A1 standards to be added a min cetane index check; IMHO this added test should not be perceived on the price at the pump. Nevertheless, after over 1.5 Mhours of in service experience using Jet fuels around the world, there is no known service difficulties reported, so...
On the known certified brands, lubricity testing has been done with fuel meeting the minimum jet fuel lubricity specifications (the SMA fuel pump/injectors exceeded 30 000 hours with no issues, i.e. many many times the TBO !).
Gelling: Another invalid concern; With all airworthiness authorities this was evaluated for the engines and airframes wrt the minimum gelling points specifications (if I recall -41?C (-41.8?F) for JET-A and -47?C (-52.6?F) for JET-A1). Further, to define the restart envelope in 2005 we have done engine inflight cold soak/restart testing with the SMA engine (gravity feed on the C182 we used) in Northern Canada with OATs below -35?C using JET-A1. Further, the SMA installations do not return the hot fuel to the thanks but rather work on a firewall forward fuel recirculation. Note also that the Cessna 406 Caravan II and Cessna 208 Caravan are certified to use JET-A up to 30 000 feet (pretty cold there !) and don't have limitations and speeds that could get you to benefit from any Ram Rise (note that where the fuel is in a wing is surrounded by air at temperatures lower than the free stream OAT - because of the lower static pressure which keeps you up there !). So all that Exxon **** is just pure CYA and talk about what they appear not to know. I hope they still know how to make aviation fuels !
The only reason I see why Exxon came out with this is that they are about to barely meet the jet fuel specs using carpy products which they know will not meet the needs of diesel engines, that to likely squize more money on the barrel (they have to make-up the recent losses!).
