206 Hydrolic Filter

[fan]

hello

having a bit of a debate here regarding the hydrolic filter on the 206 and looking for some outside point of view .......i understand that the red indicator button works with differrencial pressure and gives a positive indication of restricted flow thru the system.....and that it is a fairly early indicator considering that it pops with a 70psi differencial pressure on a system that run aprox at 600psi.....the debate is this : does it indicate an impending bypass or not in other words what happens if the filter gets completly cloged ???? is there a bypass ?couldnt find any info on that even though the FM states in the walk around section of the preflight to inspect the bypass indicator :)according to some supreme powers at be up there, way up there,t(,there is no bypass and i have a different opinion .so im always willing to learn.......

[skullcap]

206A or B it is impending bypass. Filter plugs you lose your hydraulics, do not want impure oil with possible fod to get in servo and cause much more grief.

 

206 l series has two filters and one does bypass.

[Hazy]

There is no bypass on the pressure side. There is bypass on the return side of the longranger, because it has another opportunity to get filtered before the fluid gets to the servos.

[Heliian]

Previously, when the hydraulic impending bypass indicator popped, it was a sign that the filtre needed replacement/cleaning. Now, they have a scheduled replacement/cleaning interval at 300hrs. So a bypass indicator now means that there are contaminants in the system beyond normal operating conditions. PFC includes checking for impending bypass indicator extension, you might have to open up the front doghouse on the longranger to see the filters/popouts. You should notice the popout before the system becomes completely clogged. I've never seen a 206 series hydraulic system become completely clogged but I've changed lots of old/dirty filters because of the popout. Also, the upgraded hydraulic system available in the L3 and standard on the L4 and 407 runs at 1000 psi.

 

Happy trails,

 

I

[fan]

thanx a lot for the replies......and im talking exclusively about jet rangers 206B. my understanding was that if the filter got completly clogged the fluid would bypass the filter, but obviously that would be very very short lived as the asociated fod would result in a system failure in a promp fashion

[skullcap]

System failure is the least of your concerns regarding fod, it could lead to hardover or one way locking of servo(servo moves one way but not another). Fod from a auxillary hydrualic power pack led to a military kiowa crash killing the pilot years ago. If you have problem with hydraulics, you need to be ready to turn them off and leave off until shutdown.

[Batmat]

System failure is the least of your concerns regarding fod, it could lead to hardover or one way locking of servo(servo moves one way but not another). Fod from a auxillary hydrualic power pack led to a military kiowa crash killing the pilot years ago. If you have problem with hydraulics, you need to be ready to turn them off and leave off until shutdown.

 

 

You are right about the fod, a hardover is a lot more likely to kill you than a total loss of hydraulic pressure in a 206A/B. As said before the pressure side filter does not have a "bypass" feature, when the button pops it indicates a impending "clogging" of the filter.

[skullcap]

Yes, my bad,,,filter is clogging,,,hence why when filter clogs there is a loss in hydraulics. We had one in an Astar years ago when there was a change in type of hydraulic oil and filter plugged and caused a partial loss in hydraulics. Filter was black and full of crap as new oil had different additives which were very effective at cleaning the system.....to my knowledge all hydraulic systems do not have bypass abilities on pressure side filters. 206 filters used to be very suspectable to cold weather causing the pop ups to show if a start was done on cold aircraft. Then was the controversy of flying it with the pop up showing.....but common sense prevailed as was only when cold and differential pressure existed thus push the button down and check again after hydraulics warmed up.

[dimit]

Some time ago I had a filter blockage and partial loss of hydraulic controls on a 206A. I followed the FM instructions and it was a non-event. The red popout was not extended when I did the DI the previous evening nor at the preflight that morning. I flew less than an hour that day. Don't remember what the problem was eventually attributed to, other than filter blockage.

 

I try to call the red popout the "filter indicator" rather than the "bypass indicator". "Red popout thingy on the hydraulic filter" works too, but doesn't sound a professional.

 

DM