IDG with no filter installed!!!

[adarob]

hey folks


i was in a discussion with my friends few days ago. we were talking about if we forgot to install the filters on the IDG. what the scenario that gonna to happen, i mean after we run the engs. is it gonna to leak or execute an auto shutdown or pop-up any EICAS msg shows that filters rnt installed ???

[Tu.114]

Which type are You talking about?

Generally, the AMM will have answers to Your questions. Failing that, ask the manufacturer of the IDG in question for advice, they will know best how to handle their product.

[adarob]

Which type are You talking about?

Generally, the AMM will have answers to Your questions. Failing that, ask the manufacturer of the IDG in question for advice, they will know best how to handle their product.

actually am talking bout ge90 engs. as far as i know it has a filter clogged msg. but what bout filter not installed???

[Brigantee]

I think perhaps you should entrust this task to someone qualified to do it correctly..

[IFixPlanes]

If you don´t understand / know how the "filter clogged" message is being triggered, you should really follow the advice of Brigantee!

[NSEU]

If you don´t understand / know how the "filter clogged" message is being triggered, you should really follow the advice of Brigantee!

In his defence, he appeared to be asking if there was a separate message.

Does removing the GE90 IDG oil filters cause the entire oil contents of the IDG to appear on the tarmac? If this is so, then I'd imagine you would get a few messages :}

[tdracer]

I'm not overly familiar with the GE90 (haven't worked it for over 15 years), but filter bypass is indicated by a delta pressure measurement. On the older engines it was a switch that tripped at a preset delta P - newer engines use a transducer to measure the delta P and set the EICAS message when the delta P exceeds the preset level (I'm reasonably sure the GE90 falls into this category).
I don't know if the GE90 IDG would leak oil if the filter was missing, but assuming it doesn't there would be no indication. The delta P through the filter would be zero since there wasn't a filter so EICAS would be none the wiser.

[fruitloop]

What tdracer said....And yes it has happened...

[bcgallacher]

As I recall the filter housing on Sundstrand IDGs is sealed by the filter housing cap whether the filter is installed or not - just a normal 'O' ring. Without a filter failure of the IDG would be accelerated and on failure you might get a goodly amount of junk in the oil cooler.

[riff_raff]

Some IDG's have a traction type CVT that is very sensitive to oil temperature, flow rate of oil for cooling, and very tiny debris particulate contaminants in the oil. The oil filter system typically includes a bypass valve that allows a continued flow of oil in the event the filter element becomes sufficiently clogged to prevent adequate flow of oil for safe operation of the CVT. The filter system often uses a differential pressure sensor (sometimes called an impending bypass sensor) to indicate that the oil filter element requires replacement.

Depending on the particular IDG design, it might be possible for the IDG to operate without having a filter element installed. The oil filter differential pressure sensor and bypass valve are typically designed to deal with a drop in pressure from the filter inlet to the filter outlet. If the absence of a filter element did not cause leakage or disrupt oil flow from the filter system inlet to its outlet, then it might function without any indication of a problem.

[Piper19]

I've changed a lot of oil filters in my life, also on the GE90. It's very simple, the filter in most jet engines is a disposable element, that has a mechanic feature on one side that opens a shutoff valve in the filter housing when installed. So, no filter installed = no oil flow = same message as blocked filter.

[yotty]

Piper19 are you referring to an IDG or engine filter?

[Piper19]

Yes I was thinking wrong as I'm speaking of engine filters indeed. However, I don't recall IDG filters having the same safety built in, nor do I see the need of it. You screw up the IDG of course, but that's why the disconnect feature is there. If it can be of any clarification: we once had a teared IDG filter, so some of the oil was bypassing the filter, and we had to change IDG and oil coolers in the system. So I think it's possible to run the IDG without filter, but if there is any particles in the system, everything is to be written off.