Are there screens in fuel tanks?

[FloridaMan]

One of the tabs broke off of my fuel cap (thanks Signature) and I cannot locate it in my tank and am on the road. Are there finger-sized screens in the tanks of the 1967 m20f or am I at risk of contaminating the lines and will need to disassemble the tanks before departure? 

[gsxrpilot]

The fuel pickup has a screen covering the tube. I'll see if I can find a picture for you. The part might be hiding in the corner under the pickup.

[gsxrpilot]

Here's a picture from another thread. You can see the end of the pickup tube is covered by a screen.

[carusoam]

Can you get an iPhone down the hole?  Pictures, video, or light may be helpful...

Important: Use caution sending any electrical device into the tank.  Enclosed in a ziploc or two might be a good idea...

PP thoughts only, might not be a good idea...

Best regards,

-a-

[N201MKTurbo]

There is no oxygen in the fuel tanks, it would be hard to light it. 

Here is the hot ticket: http://www.oasisscientific.com/vividia-va-400-rigid-usb-articulating-borescope-videoscope-inspection-camera.html

im not sure how well it will tolerate fuel, but it should be fine on an almost empty tank. 

I wouldn't worry about the piece of metal too much. My boss dropped a piece of his fuel sampler into the tank of his A36 and we found it with the above borescope.

[Shadrach]

3 hours ago, Antares said:

One of the tabs broke off of my fuel cap (thanks Signature) and I cannot locate it in my tank and am on the road. Are there finger-sized screens in the tanks of the 1967 m20f or am I at risk of contaminating the lines and will need to disassemble the tanks before departure? 

Highly unlikely that piece leaves the tank, if it's even in there.

[cnoe]

I greatly prefer to reinstall my own fuel caps anytime I take on fuel, but sometimes it's just not feasible to be on-site during the filling process.

If I return to the plane and find this (see below) I first document it with a picture and then bring it to the attention of the FBO management. Not to be a dick but I've had to pry the locking lever up more than once and the repairs can get expensive. If a line-person breaks my cap I expect the FBO (or their insurance) to pay for the damages.

[N201MKTurbo]

33 minutes ago, cnoe said:

I greatly prefer to reinstall my own fuel caps anytime I take on fuel, but sometimes it's just not feasible to be on-site during the filling process.

If I return to the plane and find this (see below) I first document it with a picture and then bring it to the attention of the FBO management. Not to be a dick but I've had to pry the locking lever up more than once and the repairs can get expensive. If a line-person breaks my cap I expect the FBO (or their insurance) to pay for the damages.

I hear ya! Everyone wants to help. I wish people wouldn't help....

[FloridaMan]

I greatly prefer to reinstall my own fuel caps anytime I take on fuel, but sometimes it's just not feasible to be on-site during the filling process.
If I return to the plane and find this (see below) I first document it with a picture and then bring it to the attention of the FBO management. Not to be a dick but I've had to pry the locking lever up more than once and the repairs can get expensive. If a line-person breaks my cap I expect the FBO (or their insurance) to pay for the damages.

I drained about a quart of water out of my tank after that incident as well, followed by starting on the non-contaminated tank, hard S turns, draining more water, taking off, switching tanks and flying the shit out of my airplane over the field and then landing prior to carrying passengers.


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[MBDiagMan]

It isn't a matter of being hard to get along with or making trouble For the line boy.  This is something that can be life or death.  One doesn't have to be rude, but the FBO must be told and they must care.  Fueling an airplane requires a much different mindset that is required when fueling a station wagon.

[FloridaMan]

In my case, the cap issue happened back in October, but it just broke, so they could easily deny that it was their fault. I've made maybe 20-30 flights since then, so that many cycles on the cap.


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[mooniac15u]

14 hours ago, N201MKTurbo said:

There is no oxygen in the fuel tanks, it would be hard to light it.

There is oxygen in the fuel tanks (unless they are completely full).  Below its boiling point the partial pressure of gasoline will be less than 1 atm.  The remaining gas pressure inside the tank will come from atmospheric gases including oxygen.  Depending on the temperature there may not be a combustible mixture inside the tank but I wouldn't count on it.

[N201MKTurbo]

3 hours ago, mooniac15u said:

There is oxygen in the fuel tanks (unless they are completely full).  Below its boiling point the partial pressure of gasoline will be less than 1 atm.  The remaining gas pressure inside the tank will come from atmospheric gases including oxygen.  Depending on the temperature there may not be a combustible mixture inside the tank but I wouldn't count on it.

Ok, I'll buy that, but you are correct about the combustible mixture. Just remember that most of our cars have a brush D.C. Motor  running in our gas tanks.

We all have electrical gas gauge sensors in our tanks. I sure there have been bone head mechanics that have hooked battery voltage to a gas gauge and fried a sensor, but I've never heard of someone starting a fire from it

Even if you were able to ignite the vapors in the tank with the cap off, it would make a big woosh out the cap hole and the event would be over. 

Just make sure you don't buy a plane or car from a movie company. Those things will explode in a ball of fire if you bearly brush against them!

[EricJ]

1 hour ago, N201MKTurbo said:

Ok, I'll buy that, but you are correct about the combustible mixture. Just remember that most of our cars have a brush D.C. Motor  running in our gas tanks.

We all have electrical gas gauge sensors in our tanks. I sure there have been bone head mechanics that have hooked battery voltage to a gas gauge and fried a sensor, but I've never heard of someone starting a fire from it

Even if you were able to ignite the vapors in the tank with the cap off, it would make a big woosh out the cap hole and the event would be over. 

Just make sure you don't buy a plane or car from a movie company. Those things will explode in a ball of fire if you bearly brush against them!

Submerged fuel pumps do not spark, specifically so that they don't ignite the vapor in the tank.   They're also designed to be submerged, and even when the tank is near empty the pumped fuel surrounds the pump, partly to cool it, but partly to keep fluid rather than vapor around the pump.

Fuel level senders are low-voltage for the same reason.   The vapors in the tank are most definitely volatile, but electricity itself isn't bad, just sparks, and there are easy ways around making something electrical spark.

[N201MKTurbo]

19 minutes ago, EricJ said:

Submerged fuel pumps do not spark, specifically so that they don't ignite the vapor in the tank.   They're also designed to be submerged, and even when the tank is near empty the pumped fuel surrounds the pump, partly to cool it, but partly to keep fluid rather than vapor around the pump.

Fuel level senders are low-voltage for the same reason.   The vapors in the tank are most definitely volatile, but electricity itself isn't bad, just sparks, and there are easy ways around making something electrical spark.

True enough, but that is if everything is working properly. That's why I mentioned the bone headed mechanic who accidently caused a short in the tank. If you were to hook 12 volts directly to the terminal on the fuel level sensor, parts of it would get hotter than the flash point of gasoline yet I can't find any examples of a tank exploding or catching fire because of this.

I did a quick web search of fuel tank explosions and fires. They were all caused by a leaking or ruptured tank, not from ignition from within. I found one report about vehicle arson investigation from 1958. the author stated that he investigated hundreds of fuel tank fires and they were all caused an external fire. He only saw one tank that exploded and he thinks someone put an explosive in the tank. 

[N201MKTurbo]

An example:

We were plagued by what appeared to be a fuel starvation problem in my Eclipse AWD road race car. On long lefts, it would cough and starve for fuel. We pulled the tank to install baffles when we discovered that the problem really was the electric fuel pump. The power connection had come loose and, on hard lefts, the wire would pull away from the terminal and arc! We could see evidence of arcing at the terminal. We tightened everything back down, and the fuel starvation went away. Point is, even with an electrical arc in the gas tank, it didn't catch fire. Good thing, eh? Otherwise, KABOOM!

[EricJ]

 

35 minutes ago, N201MKTurbo said:

An example:

We were plagued by what appeared to be a fuel starvation problem in my Eclipse AWD road race car. On long lefts, it would cough and starve for fuel. We pulled the tank to install baffles when we discovered that the problem really was the electric fuel pump. The power connection had come loose and, on hard lefts, the wire would pull away from the terminal and arc! We could see evidence of arcing at the terminal. We tightened everything back down, and the fuel starvation went away. Point is, even with an electrical arc in the gas tank, it didn't catch fire. Good thing, eh? Otherwise, KABOOM!

The conditions for ignition are fairly tight, and I suspect that either it never actually arced, it just turned on and off, or if it did arc you were fortunate that the conditions weren't complete for combustion.   I'm sure you appreciate that anecdotal samples of one aren't conclusive.   TWA flight 800 is a counter example.

 

[ArtVandelay]

 
TWA flight 800 is a counter example.
 

Only if you believe the NTSB report.

[EricJ]

3 minutes ago, teejayevans said:

Only if you believe the NTSB report.

I forgot about the missiles, yeah.  

[tony]

....and TWA 800 had jet A not 100LL.  Have you ever tried  burning diesel fuel???  

[EricJ]

57 minutes ago, tony said:

....and TWA 800 had jet A not 100LL.  Have you ever tried  burning diesel fuel???  

I thought the question was the vapor space, not the liquid.   In some important ways gasoline vapor in a tank is worse than Jet fuel vapor in a tank (e.g., gasoline vapor doesn't need to be warmed to be at flash point).

[ArtVandelay]

Mythbusters did a episode on cell phones and gas stations, and tried to ignite gas vapors, it wasn't easy to get the right mixture.

[Shadrach]

9 hours ago, EricJ said:

I thought the question was the vapor space, not the liquid.   In some important ways gasoline vapor in a tank is worse than Jet fuel vapor in a tank (e.g., gasoline vapor doesn't need to be warmed to be at flash point).

I think you're making his point, not detracting from it.

[mooniac15u]

The accident aircraft in TWA 800 had a heat source directly below the tank in question.  On tests of a similarly configured aircraft the fuel in that tank got as hot as 145 deg F on the ground and 127 deg F at the accident altitude.

[Piloto]

On ‎3‎/‎5‎/‎2017 at 4:38 PM, Antares said:

One of the tabs broke off of my fuel cap (thanks Signature) and I cannot locate it in my tank and am on the road. Are there finger-sized screens in the tanks of the 1967 m20f or am I at risk of contaminating the lines and will need to disassemble the tanks before departure? 

There is a rib between the filler hole area and the fuel pick up screen area. So the tab will not even reach the fuel pick up area. No need to expedite the tab removal right away. Wait until there is no fuel in the outboard compartment and then have it removed through the filler hole.

José