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As for the difference between the DI and IDI, here again, both have their own advantages and
disadvantages. For instance, amongst other things, the DI tends to produce more noise, more
vibrations and more harshness than the IDI. On the other hand, the DI gives way to a lesser fuel
consumption than IDI. However, the use of the common rail technology, which seems to be only
applicable for DI, tends to combine the advantages of both DI and IDI.
FUEL SYSTEM
With the TAE 125-1 installed, only two draining points are to be found, a main tank drain valve and a
fuel drain valve.
OIL SYSTEMS
The TAE 125-1 includes two separate oil systems, one for the engine, and one for the gearbox, each
system requiring its own very specific type of oil. Be aware that these oils are not available at the BP
refuelling services at Antwerp/Deurne airport, and must be obtained through Maintenance.
The engine oil system
Let us first emphasize that, according to the “Supplement”,
the only approved oils are Shell EP
75W90 API GL-4 and Shell Spirax GSX 75W-80
The engine oil system is a wet oil sump system containing up to 6 litres. A wet sump system means
that the oil is stored in the engine’s casing rather than in a tank (in which latter case one talks about a
dry sump system). The oil level can be checked by means of a dipstick located on the upper center
nose cowling. It should not be less than 4.5 litres, as indicated by the level being between two red
markers at the extremity of the dipstick . The maximum engine oil consumption should not exceed 0.1
litres/hour.
The system is rather straightforward: its main line supplies the various engine parts with the
necessary engine driven supply pump, oil pressure sensor, oil filter and oil temperature sensor, the
used oil being then returned partly by gravity, partly via a so-called catch-tank and associated gear
pump, back into the sump. An additional oil line supplies the turbocharger, and also drains into the
catch-tank.
Downstream of the oil filter, a thermostat ensures that whenever the oil temperature is lower than
78°C, the oil streams directly to the engine and the turbocharger. If the temperature is between 78°C
and 94°C, the oil is partly directed to an oil cooler adjacent to the cooling fluid’s heat exchanger (see
below), then further through the normal path. Above 94°C, all of the oil goes through the oil cooler,
thus ensuring a maximum oil temperature of 140°C.
Note that, although the maximum oil pressure is normally 6 bar, when starting in cold weather
conditions, it is allowed to build up to 6.5 bar for up to 20 seconds. Assuming a low oil pressure
condition, this will activate the “OIL” warning on the original annunciator panel.
The gearbox oil system
This is also a wet sump system, the oil being used for lubrication and cooling of the gearbox, as well
as for the propeller’s constant speed unit. The gearbox oil is not the same as the engine oil: according
to the “Supplement”, the Shell EP 75W90 API GL-4 type is solely to be used.
The system contains only 1 litre. The oil level can be checked by means of a viewer located behind a
small panel at the left lower front side of the engine cowling.
Note: Although the engine and gearbox oil pumps are said to be engine driven, in fact
they are one single unit, known as a combined system, driven by the gearbox.
Versie oktober 07
