Air filter broke in flight

[AirbusPilot]

Hi Folks,

Anyone have expirience this kind of air filter failure in flight???

Please give me some advise I don't want it to happens again.



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[tcone1]

I've never seen one do that before.

As a guess, it would seem that you had a backfire...probably at startup.

[Sam Buchanan]

Originally Posted by AirbusPilot

Hi Folks,

Anyone have expirience this kind of air filter failure in flight???

Please give me some advise I don't want it to happens again.



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Yes, looks very much like the filter in my buddy's IO-360-powered RV-8 after a backfire during a hot start. It managed to blow the filter all the way out of the plane one time.

[frazitl]

Sure looks like a backfire to me. Do you have a sniffle valve?

[AirbusPilot]

Originally Posted by frazitl

Sure looks like a backfire to me. Do you have a sniffle valve?

Yes I have a sniffle valve.

How can a back fire destroy the filter and not to damage the fiber glass snorkle

How may I prevent this to happens again????

[rvbuilder2002]

Originally Posted by AirbusPilot

Yes I have a sniffle valve.

How can a back fire destroy the filter and not to damage the fiber glass snorkle

How may I prevent this to happens again????

A back fire doesn't mean Fire comes all the way back to the filter. Back fire just means fuel/air mixture burned somewhere within the induction system. This produces a lot of pressure just like it does within a combustion chamber. If the pressure is high enough it can blow out the filter.

As for preventing it... I have been flying RV's with fuel injection and a snorkle for more than ten years and I have never had a backfire. With that being said it could be your starting technique or an issue with your airplane (or even a little of both).

First place to look...If your engine has two standard magnetos and only one of them has an impulse coupling (typically the left one), make sure your ignition switch has the grounding bar installed for disabling the non-impulse mag while starting. If you have an impulse and a non-impulse mag and you are using separate toggle switches for the mag switches, make sure you are only switching on the impulse mag for starting (switch on the non-impulse mag after start).

[AirbusPilot]

Originally Posted by rvbuilder2002

A back fire doesn't mean Fire comes all the way back to the filter. Back fire just means fuel/air mixture burned somewhere within the induction system. This produces a lot of pressure just like it does within a combustion chamber. If the pressure is high enough it can blow out the filter.

As for preventing it... I have been flying RV's with fuel injection and a snorkle for more than ten years and I have never had a backfire. With that being said it could be your starting technique or an issue with your airplane (or even a little of both).

First place to look...If your engine has two standard magnetos and only one of them has an impulse coupling (typically the left one), make sure your ignition switch has the grounding bar installed for disabling the non-impulse mag while starting. If you have an impulse and a non-impulse mag and you are using separate toggle switches for the mag switches, make sure you are only switching on the impulse mag for starting (switch on the non-impulse mag after start).

Here is my hot start technic (from lycoming manual)

Mixture ICO
Throttle Full
Boost pump off
Just left Magneto ON (the one with impulse coupling)
Cranck

Once engine fire
Mixture rich
Throttle idle
Magnetos both ON

This technics works every time, I have try some other with the throttle in different position than full, because I have read here full throttle technics could be dangerous but I have been not able to start the engine and I have run out of battery.

Please give me some advices

[Bavafa]

Fernando,
I use the exact same technique with the exception that as I crank I start pulling the throttle to idle. At some point (usually about half way) it starts. The idea is that by pulling the throttle to idle, the engine finds a position that the air/fuel mixture is just right for starting.

Hope this helps.

[cdmiller]

Fernando,

I had the same problem on an RV-8 with an IO-360 M1. When I started it the first few times the engine backfired and blew the filter element out of the filter box. It also happened during a flight. It turned out that there was a timing problem with one Magneto. The points were broken (brand new mag). Once the magneto was repaired and timed properly, the problem went away.

Dan Miller
RV-8 790 hours

[Steve A]

I had this occur serveral times and I attributed it to a backfire. I ended up putting a screen over the filter to prevent it bending and subsequently pulling out of the bracket holding it in place. I think my starting technique has improved as this occurred when I first started flying my plane, I am confident the loose screen keeps the filter in place regardless.

Steve Anderson
RV 7A Flying
130 hours
Lafayette, La.