ENG FUEL FILTER

[rotary]

We got a momentary ENG FUEL FILTER eicas on our 767 two days ago after thrust reduction during a cruise climb at FL320.

Did all the good stuff by advising MOC in good time to make a plan, 5 hours to destination.

While reviewing the tech log for the same aircraft this morning I discovered that the only work recorded on my log entry was, Status msg cleared, found satis.

The next flight after mine, they got the same warning during climb out after take off. Fuel filter was changed at destination, NY, before further flight.

My query is,after 8 yrs flying this and the 757 I have never seen this EICAS and was surprised that maintenance did not immediately change the fuel filter.

Is there a standard maintenance procedure for this? Is it usual to just clear a status msg for something like this?

I would be interested to hear from engineers as well as crew on this.
Merry Christmas

[sb_sfo]

Can't offer an opinion without knowing what motors you have, other than to say that a momentary message may be nothing more than a transient electrical fault.

[Mr @ Spotty M]

I think he is on the GE CF6-80C with the yellow paint work.;)

[rotary]

Engines are GE CF6-80C2B7F.

I did think that it may be a transitory electrical msg but as it happened on the very next flight as well I thought there might be something more.

Flew it to Lagos today and no further msgs after filter replaced.

Merry Christmas

[Kuchan]

It is a sign of fuel filter starting to clog up the filter.

It is normal routine to change fuel filter for any sign of clogging as nowaday it is on condition to change it between "C" checks.

Electrical fault can be intermittent but at random power setting , not after thrust reduction.

[Beeline]

Would be interested to see if they have recently performed maintenance in the tanks.

If MSG was latched, personally I wouldn't pen off a fuel filter clog MSG even on a tight turn, could be a lump of sealant or tank contamination.

Minimum would be an engine run but that would need to be above idle. Quicker to change the filter if you have one.

[Terry McCassey]

Don't think I would run the engine above idle after a filter change. Leak check only at idle should be OK

[spannersatcx]

You would of course do what the AMM says!:ok:

[Kuchan]

Minimum would be an engine run but that would need to be above idle. Quicker to change the filter if you have one.

Yes it is quicker to change the filter than troubleshooting with engine run. After all, it would not show the filter clogging at idle or even at High idle in most of this intermittent fault scenario.

Idle run is good enough to leak check after a filter change.

[Mr @ Spotty M]

As usual spannersatcx, is spot on, the AMM will have the details of what is required, especially what type of engine run is required. :ok:

[Golden Rivet]

close but no cigar...

The FIM is your first port of call....

The standard maintenance procedure in this instance is to is inspect (replace) the fuel filter.

[spannersatcx]

of course the FIM would be the first port of call, but that is not why the statement was made, the FIM would tell you to replace iaw AMM .... which would tell you to c/o EGR iaw AMM ....

The reference to the AMM was because it was being intimated that some would do this some would do that, when of course you would do it as per ........ simple really! :ok:

[Mr @ Spotty M]

As l said previously spannersatcx is spot on with his comments.
In the case of the B767 with CF6-80C2 engines, you carry out a dry motor after replacing a fuel filter element.
You would be surprised on what type of engine run is required after changing some components.
The same engine type on the A300-600, requires an engine run of 80% N2 for 2-3 minutes, if you change a starter motor.
However on the B767 it is only recommended, the minimum is an idle run.
spannersatcx will always rightly say, follow the AMM. :ok:

[Terry McCassey]

A starter motor is different from a fuel filter and so the post installation checks are different. A starter motor installation can cause gearbox oil leak issues whereas a fuel filter does not. Without doubt, the AMM is the book of choice but I will stand corrected if an above idle ground run is required to leak check a (LP) fuel filter change. Flack umbrella now open !

[Mr @ Spotty M]

As listed in my post, all that is required as per the AMM for this instance is a "dry motor". :ok:

[mono]

I don't have access to the AMM as I no longer work the 767. However I'm curious as to how a dry motor would be sufficient to check the fuel filter for leaks? An oil filter I could understand, but you need to pressurise the fuel system in order to check for leaks. So unless you open the fuel cocks (a wet motor or idle run) I don't see that you're checking anything!

On the initial subject, I must confess I would have thought the filter should have been checked (replaced) at the first instance. It's not as if it's a difficult job.

[grounded27]

Fuel pump is connected to gearbox, the fuel filter will pressurise with a dry motor. @ The O/T the signoff was probably not correct but every filter on an engine will bypass (what triggered your eicas message) as clogging is expected to happen eventually, no ones life was put in danger.

[Terry McCassey]

Think this is going to differ between aircraft types. The B77W requires test 2 and test 5 after a filter change. That is a dry motor and an idle leak check per MM 71-00-00 p504

[A33Zab]

An oil filter I could understand


Really?......For a GE CF6 with lube oil pressure just above LOP trigger of 10 PSI @ max. motoring.....
resulting in only a few PSI for a thick fluid in the scavenge filter?

Fuel pressure in the fuel filter will be anyway above 25 PSI during the dry motoring cycle
and this will be sufficient for a leak check.

@grounded27:ok:

if the intermittent ENG FUEL FILTER (delta P 21-26 psid) messages are more regular it
will be time to reduce the filter element replacement interval. (normal 4500FH).
A reduced interval (150 FH for the 1st 1000 FH) should already be in the maintenance program
after delivery, fuel tank repair, volcanic ash encounter and fuel tank contamination
(and after biocide treatment!)

But as already stated AMM (and company additions) will contain the proper procedures.
http://i474.photobucket.com/albums/rr101/Zab999/GEFF.jpg

[Mr @ Spotty M]

You are correct with your fuel filter maintenance programme assumptions, apart from the normal replacement interval is 6000 FH.