Jump to content

Inlet Barrier Filters


Recommended Posts

  • 2 weeks later...

Hey fleman, flown Longrangers with and without so here’s my opinion. The IBF does add cost and it can effect performance. However it f you regularly fly in sandy environments or snow I think it’s a good idea. The particle separator stops the big stuff but sand and dust can still come through. Erosion of the compressor blades is inevitable if you do that a lot with no filter. I did fly one Longranger without even particle sepersator. We nicknamed it the “Bare Dog” instead of the “Long Dog”. Didn’t make me feel warm and fuzzy out in the bush without maintenance support for compressor washes. In Hawaii I flew Airbus helicopters with no filters. However the company did daily water and weekly zoc compressor rinses. Also they only land in pre approved spots so no bush dusty landings.


So my opinion, if you don’t land off airport in dusty spots and do compressor washes often the particle separator is fine. But if you’re working in the bush or snow go for the IBF. In snow if the filter clogs you can open the IBF doors to avoid loss of air to the engine. If the particle separator clogs up, well you’re SOL hope you can land immediately before engine starves. The snow scoops over the intakes do work pretty good, but the particle separator swirls can plug up. Some machines have a purge to blow bleed air for cleaning. Obviously reduces power. I would do it immediately on skid touch down if power limited and landing in dust. The IBF system gives you a light with pressure sensor so you have the option to open the inlet doors and land without such urgency if the filter is clogging. But the filter does a great job of keeping your compressor clean. A bit of extra maintenance to clean the filter as needed but no big deal.


In Canada I have never flown an Astar without a filter. Peace of mind going into tight spots, and imperative for heliskiing. The 212 I’m flying now has a different but effective particle separator system so after market mods aren’t needed.


So how often do you land in the dust and what does the compressor look like after rinse? That will determine if it’s worth the cost of going IBF. Peace of mind, well that’s harder to put a cost on.


Happy Landings,



  • Like 1
Link to comment
Share on other sites

Thanks for the information!


Any info about what kind of performance boost you may get with the IBF? Looks like it would save a bit of weight but not sure if we would see a performance boost beyond that.


We are not in a super dusty environment (Papua New Guinea) but pretty much all of our landings are off airport. Always a bit of dust kicked up.

Link to comment
Share on other sites

As for performance... I have heard several times on several airframes that IBFs do provide an increase in power in certain designs by absorbing heat from the air as it passes through the filter element, thereby reducing inlet temperatures in the plenum prior to going to the engine. When we first were fielded IBF for the Black Hawk, we tried an experiment hovering with the (gigantic) bypass doors open and closed in high ambient temperature, and while it was small, I observed a slight decrease in TGT (TOT) operating with the bypass doors closed. Unfortunately the flat plate drag the IBF on the Hawk added was the significant drawback for cruise speed, and it was working in conjunction with a particle separator which further reduced any "power advantage". The performance charts were ultra conservative and thus led most pilots to dislike them.


In our fleet of 206s, the one with an IBF does have stronger power check numbers than the particle separator bird, unfortunately our inlet screen bird has a different model engine so no comparison there. I personally am a fan of them none the less.

  • Like 1
Link to comment
Share on other sites

  • 3 months later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...