getting to grips with COLD WEATHER OPERATIONS 寒冷天气运行(64)

. Pratt and Whitney  : 0°C 
. Rolls Royce  : 0°C 
. General Electric  : 3°C 
. IAE  : 4°C 

.
 CFM (A319/A320/A321) : 4°C

.
 CFM (A340) : 5°C

b) Fuel heat management system limitation
This limitation reflects the engine capability to warm-up a given water-saturated fuel flow
to such a point that no accumulation of ice crystals may clog the fuel filter.
Such a limitation does not appear in the documentation for some engine types when
outside the environmental envelope.
When applicable, the resulting limitation is a fixed temperature below which, flight (or
takeoff only, if high fuel flows only cannot be warmed-up enough) is not permitted.

The most restrictive of the two limitations above (a and b) should be considered.
Note: The fuel anti-icing additives authorized by engine manufacturers decrease the freezing temperature of the water contained in the fuel (decrease the fuel heat management system temperature limitation), but have no effect on the fuel freezing temperature itself.
Furthermore, an additional 2°C margin for temperature indication inaccuracy has been requested by airworthiness authorities for A300/A310 aircraft.
Therefore, the minimum fuel temperature should be:
FUEL FREEZING POINT
+ ENGINE MANUFACTURER MARGIN
(+ 2°C for A300/A310)
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The fuel freezing point to be considered is the actual fuel freezing point.
If the actual freezing point of the fuel being used is unknown, the minimum fuel specification values as indicated below should be used as authorized by the AFM/FCOM.
JET A  JP5  JET A1/JP8  RT/TS-1  JET B  TH  JP4 
-40°C  -46°C  -47°C  -50°C  -50°C  -53°C  -58°C 

Note 1: The freezing point, as defined in the ASTM test methods, is the temperature at which the visible solid fuel particles (waxing) disappear on warming dry fuel (water free) which has previously been chilled until crystal appear. However, for Russian and some other Eastern European fuels (RT, TS-1, TH) using the GOST test method, the fuel freezing point is equal to the temperature at which solid fuel particles first appear, (waxing) when cooling dry fuel. This means that Russian fuels with a declared freezing point of -50°C under GOST specification would have an equivalent freezing point of -47°C when tested to ASTM method. Hence JET A1, RT and TS-1 normally have the same fuel freezing temperature.
Note 2: The freezing point temperature for Russian RT and TS-1 fuels is dependent upon the region. RT and TS-1 fuels have maximum fuel freezing temperatures of -50°C for all areas where the ground level air temperature is not below -30°C during 24 hours before departure. For areas where the ground level air temperature is below -30°C during 24 hours before departure then upon customer request the following fuel freezing temperature specification applies RT: -55°C and TS-1: -60°C.
　
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