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inside fuel tank strainer inspection

S

seagull

Well Known Member
On the early -12 fuel tank can the fuel strainer be inspected with a bore cam through the filer tube? Can a bore cam cause an explosion? Should the tank be empty or full? I did not build the tank, can the strainer be accesed by removing the fittings on the bottom?
I know of SB-00070 but have not done that yet, besides I assume I am looking for deterioration of the strainer or debris so how would that be serviced?
 
Full tank. Once the bore cam's head is in the fuel, there's no oxygen. I've done it a few times already.. can't say I'm not nervous doing it though!

Its like when they tell you that you can grab onto a 120v line as long as you're insulated.. sure.. makes sense that you can do that.. but I'm still going to have sweaty hands if I actually had to do it!

Can't speak to legacy -12 strainer though. only that you have an easier time seeing it with the camera than us -12iS folks.
 
It would be great to find an "explosion proof" borescope. Another option is to use a gas like CO2 to displace all the oxygen in the tank before inspection. Probably not that critical on the deep and narrow RV-12 fuel tanks, but on the RVs with wing tanks, a bit more difficult, unless the tank is completely full - and even then there is a chance of air bubbles trapped at the top where the ribs are.

https://patents.google.com/patent/US5904190A/en
 
The OP asked if the 912ULS fuel tank strainer can be accessed with a borescope via the filler neck. There is a sheet metal dam positioned around the exit fitting to prevent the tank from un-porting when low on fuel. That, and the fact that the strainer is located diagonally at the other end of the tank, makes me think that a borescope isn’t capable of negotiating the double-bend radius necessary to see the strainer.
 
I inspected the strainer today, no BOOM.

I siphoned the tank, then drained the remainder through the gascolator with the help of the fuel pump. Then I ran a airline into the gas tank with 5psi air flow for 2 hours to evacuate the vapors. I removed the filler neck at the coupler and put the bore cam inside the tank, it wasn't hard to find and look at the strainer. This was all done with the tank in the plane without removing any fittings.

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So, we look at the fuel tank strainer and see that’s its clean of debris. I wonder if anyone has found anything of significance when doing this inspection? Something large enough to block >50% of the screen? I don’t think so…

The strainer has a very large surface area and very large mesh. I doubt if it would catch anything that passes through the inline filters at fueling pumps… be it Mogas or Avgas. Even if a large piece of debris (perhaps fuel tank sealant) is floating around it will most likely never attach to the strainer because of the violent sloshing in the fuel tank. Bottom line is… the strainer is necessary and very well designed... it is self-cleaning to keep large particles in suspension with the fuel and prevent large particles from entering the electric fuel pump.
 
Piper J3 said:
So, we look at the fuel tank strainer and see that’s its clean of debris. I wonder if anyone has found anything of significance when doing this inspection? Something large enough to block >50% of the screen? I don’t think so…

The strainer has a very large surface area and very large mesh. I doubt if it would catch anything that passes through the inline filters at fueling pumps… be it Mogas or Avgas. Even if a large piece of debris (perhaps fuel tank sealant) is floating around it will most likely never attach to the strainer because of the violent sloshing in the fuel tank. Bottom line is… the strainer is necessary and very well designed... it is self-cleaning to keep large particles in suspension with the fuel and prevent large particles from entering the electric fuel pump.
Click to expand...

Jim, I totally agree with you. At 1250 hours, (supposed to be checking every 100), I wanted to see if I was missing something, why it was so important to check this strainer that a SB was put out to give better access. I wonder how many check theirs at 100 hr intervals.
 
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