If your job is Jet fuel compliance then this suggests that fuel quality is important although I have no knowledge of what parameters in the fuel may be of greatest concern and why. Maybe you could enlighten us.
What is the most common cause of non compliance?
What causes this non compliance?
Why is this deemed a concern?
Incidentally what happens to fuel that doesn't meet spec?
My job is not routine compliance testing (though it was a decade
or so ago), we only get involved once problems are identified.
Perhaps not surprisingly, the most frequent problem by far in Jet fuel is failure of the simplest test available - visual appearance, where the spec is
"Clear, bright, and visually free from solid matter and undissolved water at ambient temperature". Generally, this problem can be solved by simple filtration. In extreme cases, the fuel is downgraded to regular kero or blended into gasoil.
Another common problem is flashpoint, particularly if the fuel is transported at sea after a previous low flash cargo. Reduced flashpoints are very difficult to resolve, necessary blend ratios are impractically large. Typically, the most economical action can be to re-refine the material, but that will always pose production problems to a refinery that is probably already maximising Jet output - additional kero in the crude stream will reduce output of gasoil and gasoline.
An interesting one, and possibly of relevance to BA038, is particulate contamination. This is measured by filtering some fuel, and weighing the particulates collected. An associated test (which forms part of the military spec) is filtration time, which specifies the minimum time for 1 US gallon to be vacuum-filtered. We have had numerous problems where anti-icing additives have been incompletely mixed, which for reasons we dont fully understand, cause difficulties in filtration. Obviously, filtration difficulties would impact on the flow of fuel through aircraft filters, and I would imagine that the effect would worsen with decreasing temperture. However, I have no idea if the subject fuel contained any FSII - chances are it didn't. I also don't know if the AAIB have had particulate contamination/filtration time checked as strictly speaking, the limits only apply at the point of manufacture. It would seem unlikely that they haven't checked this basic point however.
The remaining common failure is the JFTOT (Jet fuel Thermal Oxidation tester"). This arises where the fuel storage or transportation includes incompatible metals such as copper. It can generally be treated by the addition of approved metal de-activator additives to the fuel.
I suggest that you missed my point.
I didn't, but concede that I didn't answer it properly!
I did not intend to convey that the fuel in the subject aircraft was substandard in some way (the AAIB appear to have eliminated this by stating that the fuel was "in spec") but merely pointed out that ACCEPTABLE "quality" appears to have a wide range.
I certainly didn't suggest that the fuel was "so bad" that it wouldn't burn, for the reason you pointed out (would have been determined during take off/climb) but since Cal value = heat from fuel = Thrust, a lower cal value will give you less "bang for your buck".
HOWEVER, this wide range of acceptable quality MAY.... in some yet to be determined way..... have been implicated in the chain of events that occurred to BA038.
As I stated I suspect we are talking about STANDARDS / SPECIFICATION /PROCEDURE boundaries in some way, otherwise the cause would have been determined by now.
Briefly dealing with the "bang for buck" point first, the answer I give below should hopefully answer the main query posed by you and others, which I interpret as "even though the fuel meets spec, could the wide range allow the presence of unsuitable components that wont burn properly"
Specific energy for Jet is specified at minimum 42.8 MJ/Kg. However, it does not have to be measured. Instead, it is acceptable to calculate the specific energy based on certain measured quality parameters (density, distillation recovery temperatures, aromatics content, and sulphur content). This shows that the authorities consider it reasonable and safe to conclude that a fuel which meets spec for those key parameters must produce sufficient energy, even if the material is not wholly "kerosene". Rest assured, this has been based on years of research and analysis. Clearly, they do not consider that other materials with similar parameters but adverse energy characteristics could be substituted. In any event, other burning characteristics of the fuel such as smoke point are checked.
However, I (and presumably the AAIB) accept that while this is a reasonable assumption, it would have to be checked out for the subject fuel. I would be amazed therefore if they have not yet measured the specific energy of the fuel. The point remains however, if the SE was low, the aircraft would never have got off the ground. Also, flamibility issues could not account for the apparent cavitation damage.
SOMETHING caused this incident
Certainly did, and its clear that the fuel has to be one of the major suspects. However, if it was, I would suspect it was more to do with its fluidity/pumpability in a combined low fuel temperature/lowish fuel quantities (minimising the net positive suction head available) environment than any other quality issues. (Cant recall whether I've mentioned this before, but the viscosity of Jet is specified only at -20C)