AW 139 Technical Question.

[outhouse]

Yes I know a thread exists, however I have tried the search to find it again and no luck (old fart and computers I expect) and trawled through the back pages, so a link would help from them what know it. Though the last time I looked little info on above.
Question, Starter for 10 points: Any info on the history of “Hydraulic “failures or indicated failures. Pilot’s perspective and Engineers input welcome.
Bonus points available depending on response.

Many thanks

outhouse

[Aser]

With the new servo pressure switches the indicated failures are gone...

Not a big issue if you are talking about the "1 SERVO" or "2 SERVO" lights.

Regards.
Aser

[pitchlink]

WE have had indications of a No2 filter blockage on the systems page of the MFD. I am told this is caused by the pressure switch in the bypass being triggerd by a momentary increase in pressure as the gear is lowered, no actual blockage apparent. Have changed several pressure switches as a result

[AB139engineer]

Same issue with our ship, changing the by pass switch did nothing, and it even if you keep the gear down it will by pass anyway. Check the filter periodically to be safe. Flush your hydraulic reservior every 24 months. As far as I know Agusta has no fix yet for this poblem.

[platinumpure]

Same as above regarding bypass and servo indications. However have still been troubled with servo CAS messages after heavy rain, high humidity even with the new servo switches.

We have had a total loss of pressure on the number 1 system if my memory serves me correct. Pump made lots of scary noises from what I gather. System was isolated before pump had chance to overheat and scary noises stopped as there was still enough fluid trapped in that part of the system. Did not overheat after system had been isolated. Aircraft landed safely with no problems on the No2 system.

In addition to this we have had one instance of the No4 pump losing pressure early on shutdown. During further investigation it was found that it was actually the No 2 pump that was losing pressure early as the No 4 sensor was actually routed to the No 2 pump and vice versa. This routing was found to be the same on all of our aircraft. Maybe thats an Italian thing??? :ugh:

Hope this helps.

[noooby]

We've had the Hyd Pressure filter popping on one machine, but managed to fix it after changing the Hyd PCM (warranty :})
We got sick of changing pressure filters for no reason. I emailed Agusta and they confirmed it is a known problem, and is like that because of (according to them) two main issues.
One is that the hyd press filter is too fine. They are going to a coarser filter. It isn't because of contamination (usually!!) but because of pressure pulses. These pulses are 'stopped' by the filter, creating enough press diff to set off the press diff switch, which is the other problem. The press diff switch reacts too quickly, and picks up a nano seconds worth of press diff out of limits.
Agusta assure me (!!!) that they are working on new filters and press diff switches.
Apart from that, we haven't had any other hyd issues (touch wood :ok:)
Agusta also informed us that they don't believe it necessary to pull the press filter to check for contamination, unless the return filter is also popped. Just reset the popout. If your company requires it in writing, send an email to tech support person you use, and refer them to the guy we use at Agusta. If you need his name, PM me.
Cheers

[outhouse]

Hi,
To all that responded to my enquiry very many thanks. It’s been very informative and I am sure will be a great help. Should I experience any different problems in the future I will share my experiences with you all.
Regards

Outhouse.