cleo123
 

Cold engine , bold pilot :*

This is what it says for a PW121 engine:

"Oil temperature should be maintained above 71ºC to ensure fuel anti-ice protection. If lower oil temperature are encountered, monitor directly fuel
temperature must be greater than 45ºC to ensure adequate inlet splitter anti-icing."

Errors in sentence structure by ATR.

But, can someone explain the inlet splitter anti-icing for me.

Speaking for the PW123 and 150 engines.

See a picture of the PW150 air inlet here: http://www.k-makris.gr/Gallery_2_pics/PW150A_intake.JPG (not embedded due to excessive size). I did not find a similar picture of the 121 or 123 series, but it looks similar enough. There are many vanes, shafts etc. involved that are of course susceptible to icing.

Two methods are used to keep the inlet free of ice: firstly, the intake flange is heated electrically via 115V variable frequency. And secondly, the oil return line from the reduction gear box to the tank is routed through all those vanes to keep them warm. So in order to ensure adequate anti-icing capability, a minimum oil temperature is required.

The requirement of a minimum fuel temperature on the ATR seems a bit odd to me; it must be related to the points of measurement on the engine installation. On the DH8, it is all about the oil temperature.

Quote:
The requirement of a minimum fuel temperature on the ATR seems a bit odd to me; it must be related to the points of measurement on the engine installation.



I'm not familiar with the specifics of the PW123/150, but a fuel/oil heat exchanger is commonly used to prevent fuel icing - and that takes a minimum oil temp to be effective. So if the oil isn't warm, the fuel can't be cold enough for icing to be a threat.

Is the ATR susceptible to fuel icing? The DH8-300 and 400 have a fuel/oil heat exchanger as well, but that subsystem only has limits with regards to fuel or oil temperature associated with it and has no influence on operation in icing condition.

The quote by JammedStab however seems to directly relate fuel temperature to engine intake ice protection.

Some great, considered replies. Thanks a mill.

Just another example of how we strike the balance between commercial, safe and efficient operation I guess.

I'm going to take the question direct to P&W, but I predict they come back with the limitations of 0 & 55 degrees.

Please Let us know...
 

When you take this question, I suspect that that will come back with something like this, perhaps in more elegant terms: "Yes, dear pilot, it is mostly about achieving a stable, fully warmed operating temperature, such that all sub-systems are also able to perform their intended functions. When numbers of minutes are specified, this is generally the number of minutes of engine operating time at idle, necessary to make those sub-systems fully functional in most environments." There will likely also be some additional cabbage like, "Those operating in extreme, sub-normal temperatures may wish to extend their engine warming times or even avoid engine shut down all together." and of course, all of that is CYA stuff. In the end, be certain that everything is properly warmed before ordering TO thrust and for our own CYA cabbage, follow the company's SOPs. Company SOP, plus a fudge factor if necessary is really the only way to fully cover your own tender parts. They are not always right, but they are the rules that must be followed, simply because the God of the airways (FAA) has reviewed and approved them. Those rules may suck at times, but they are very real. In this case, you may exceed the SOP by warming a little longer, but there is no defense for undershooting SOP, especially if something goes wrong. 'tis how it is.