Has anyone seen this on a 109S panel...

[BigMike]

From our Chief Engineer:

"The No1 oil pressure caution threshold being higher than No 2 engine. In flight both engines are within 1-2 PSI however the #1 engine Oil pressure Caution illuminates intermittently whilst the #2 engine Oil pressure is in the mid range of the indicator scale. The #1 engine Oil pressure sits right on the cusp of green and yellow in all aspects of flight Have a look at the photos. The one with all the same figures and indications is the test page. All the rest are in various aspects of flight."

http://i8.photobucket.com/albums/a3/Micksphotos/A109sTestpage.jpg
http://i8.photobucket.com/albums/a3/Micksphotos/P3170041.jpg
http://i8.photobucket.com/albums/a3/Micksphotos/P3170044.jpg
http://i8.photobucket.com/albums/a3/Micksphotos/P3170045.jpg
http://i8.photobucket.com/albums/a3/Micksphotos/P3170046.jpg

Has anyone seen this on a 109 panel, and do you have a fix for it.

Thanks BM

[212man]

Well I'm not a 109 person, but my concern above would be more directed at why is the xmsn pressure in the yellow!

[spinwing]

Mmmmm ...

Interesting .... (puts on Engineers cap) ...

Have to admit I don't know anything about the 109S electronics ... but this looks like an electrical glitch.

First step is to relax ... get wet line gauge out of stores and actually check what the REAL pressure indication is.

If gauge reads the same as indicated on No1 Eng Prx per screen you then it would appear the caution light sensor is the problem. If gauge readings are "normal" then the hunt begins looking for the earth/grounding fault or the dodgy transmitter. Perhaps substituting the caution transmitter with the appropriate resistor value will make the display behave and then point you in the right direction ...

Q. On this machine does the Eng prx signal and the caution Lt signal originate from the same sensor?

Should be (Ha Ha) an easy (ish) fix! ... or perhaps a job for the "queer trades" guy??

Good Luck :ooh:

[John Eacott]

The oil pressure indications (and limits) shift with N1 in the PW207: I would take a wild guess that the N1 feed for the No 1 engine may be amiss, sending incorrect parameters to the EDU. If the oil pressure is really out of max or min limits, of course, there would also be an OIL PRESS warning.

Not sure about the high MGB pressure, maybe the px relief valve needs tweeking?

[spinwing]

Mmmm ...

John ... Big Mike did say he got an intermittent No1 Oil Prx warning ?


:confused:

[John Eacott]

Spingwing,

Yes, I missed that: thanks! However, the oil pressure limit indications on the 207C are as I mentioned, variable depending on N1. If the engines are matched, N1's equal, there should be no variation in the threshold between engines.

The No1 oil pressure caution threshold being higher than No 2 engine.

Therein may lay the problem: if the N1 signal from No 1 engine is faulty, the EDU will show an incorrect parameter for the oil pressure to comply with, hence the faulty indications. Only a guess, so don't nag if I'm wrong ;)

Agusta's graph showing the variable oil pressure limits:

http://www.eacott.com.au/gallery/d/3030-2/207C+Oil+limits.jpg

[CarryOnCopter]

BigMike,

Can see what you mean, had some problems with the EDU's on the 'Power' in the past, the first one just went blank so the other went to reversionry, interesting to start because now there is no start page so it's faith in the Fadec, one off flight only guv.

The second one was fuel indications, won't bore you with the whole story but the engineers were looking forward to getting in to the tank's but every time a pilot came back there was a different story on the indications so they swapped the screens as they are identical which sorted that out, of course this now involved $30,000 for an exchange screen (again) if I remember rightly.

The above is just a thought but those indications are strange because of the difference in cautionary range, in theory the test page goes well then it works, hmm.

The main transmission indications in the pictures show the pressure going down as the temp goes up which seems to be right, note that all of the Powers and the few Grands I have flown seem to remain in the very bottom of the cautionary range when up to temp, used to complain about it and the engineers would try something new every time till they had run out of thought's, seems that is the way it is.

[that chinese fella]

Oil pressure on nearly all light turbines is variable depending on N1/Ng.

Agree with Spinwing, dust off the wet line gauge or conversly use a dead weight tester to feed the transducer.

Good luck BM. A bit flasher than those stinky 500's eh?

[RVDT]

Knuckledraggers,

The bit you missed was the temperature. The oil system on the 109E and S is "unregulated". The correct pressure is computed from N1 speed AND oil temperature.

Look at the difference in temps. The higher temp and SAME pressure is acceptable on No.2 but not No.1. The EDU re-scales the pressure range accordingly to the oil temp AND N1.

You can adjust the pressure. See the manual and your trusty engineer. You need to set the N1 at a fixed value (selecting manual and beep the RPM on the ground) and you should have a certain oil pressure versus oil temp.

The pressure on No.1 is too low for the oil temperature and N1.

Buy lots of beverage for your engineer as the oil pressure adjustment is on the bottom of the gearbox. Like many things on this installation you can probably see it but thats about all you can do. There is a fancy tool required to make it easier to adjust.

Be aware also that you may be chasing something else. S and E models are known to have issues with the thermo valves in the coolers. Your temps seem to have a larger than normal split.

Don't expect P's and T's to ever match very often on a 109.

Sounds like you need a 109 engineer, what are you paying?

[ShyTorque]

The 109S of my aquaintance does this on occasions, albeit temporarily on start up or when large power changes are made. The engine oil temperatures on that airframe usually sit about 12 C apart with the hot engine showing slightly less oil pressure.

If an engine oil cooler thermo valve malfunctions you will know about it very quickly (seen that whilst IMC with 6 pax, diverted single engine).

The transmission pressure always sits right at the top of the green, occasionally into the yellow at 51-52 psi. Having questioned our maintenance agency they tell me "it's normal".

[Chiefeng]

RVDT

We replaced the #1 eng oil temp sensor a while ago as it was reading 20-30degrees C hotter than the #2 engine even at ambient temperature. After that the aircraft operated normally for 2-3 weeks and then started showing up with this oil px warning problem. Could it be the coil in the N1 sensor supplying the ECU is giving an incorrect signal?

As for the position, if you have Arriel, LTS101 and Allison would be happy to talk

[Mark Six]

Have not encountered this in the Powers or Grands that I have flown. Maybe a problem with the DAU software? Try emailing Alessandro Crespi [[email protected]] . As for the TX oil pressure, I am used to seeing it in the bottom of the yellow on both models. I know it can be adjusted down. Some engineers are happy to do this but others seem to prefer seeing it in the yellow rather than do the adjustment.

[RVDT]

Chiefeng,

Allison C18 thru 40/47, Arriel, PW200 Series. PT6T and Lyc T53 on the side.

Also have AUS ATPL (H) with ~300 hours on type PIC.

Trained on 109 at Vergiate. Ground and Pilot.

PM if you want to go into things deeper. Serious brass required though. ;)

[helopat]

The transmission pressure always sits right at the top of the green, occasionally into the yellow at 51-52 psi. Having questioned our maintenance agency they tell me "it's normal".

Shy Torque,

We've had the same transmission 'issue'...its not actually normal but its a simple fix. Our guys adjusted something (pressure return?) on the transmission and brought the pressure down within limits. Took about 10 minutes. Happy to discuss further if you'd like.

I know it can be adjusted down. Some engineers are happy to do this but others seem to prefer seeing it in the yellow rather than do the adjustment.

I guess its different strokes for different folks, but yellow is precautionary...why would you be satisfied that its ok to fly with the pressure there if there was an easy fix. Seems like the tail (engineers) wagging the dog (drivers) IMHO.

HP

[ShyTorque]

Helopat,

But is there actually a disadvantage of running the transmission with 50 psi and an occasional 1 or 2 psi over (before fully warmed / first takeoff)? 50 psi is the top of the continuous operations band.

I'd be much more concerned if it were 30 psi and occasionally below when hot.

[helopat]

No problem at all if its a few PSI high before coming up to operating temperature. Completely normal. HOWEVER (comma) when you're just ditty bopping along in steady state flight, the XMSN Pressure should be consistently in the continuous operation range.

I suppose that some guy with an enormous brain came up with that range, so why second guess whats ok and whats not. Green is where it should be. Like I said, we had the same problem, engineers happy to leave it alone, but we pushed the issue a little and it turned out to be a rather minor procedure to adjust the pressure down a PSI or two.

For what its worth...

HP

[ShyTorque]

Thanks for the advice.

[helopat]

My pleasure:ok:

[ShyTorque]

The psi was only 49 today. :eek:

[Chiefeng]

Thanks for all the input.
Firstly, we have fixed the problem of the oil pressure caution. It ended up being the Thermo valve in the oil cooler. After changing the valve it raised the oil temp but had no effect on the oil pressure which resulted in the oil pressure being within the parameters for the given N1 and oil temp.

Secondly the Transmission oil caution that everyone was fixated on only stays in that area until the transmission gets up to operating temp.

Once again thank you for your input.

Chief eng:ok:

[RVDT]

Chiefeng,

Just leave the money on the fridge. ;)

[ShyTorque]

Secondly the Transmission oil caution that everyone was fixated on only stays in that area until the transmission gets up to operating temp.


Yes, adjustments to the pressure should be made with an oil temperature of 70 degrees C.