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Pencil dropped in PA38 tank

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Pencil dropped in PA38 tank

Old 26th Oct 2014, 18:28
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Fakepilot if you want I can send you 100 authentic Scottish fag lighters if you like call it 10$ each.
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Old 26th Oct 2014, 19:05
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Lost the flexible end of a jerry can filler pipe in a Jodel fuel tank. Got it out using one of the flexible claw tools with a small web cam taped to it. Drained the tank first.

Last edited by baldwinm; 26th Oct 2014 at 19:06. Reason: Duplication
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Old 26th Oct 2014, 21:31
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I have just purchased a Borascope from Aldi for 60 and has a colour screen , one meter long flexi approx 10 mm wide with built in internal Led lights at camera end , comes with a few hook attachments but you could adapt your own or use in conjunction with a three claw grabber .

Just had a though " how about using suction if you can locate it in the tank"
Use a fuel pump to suck it out ?


Good luck Austerwobbler
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Old 27th Oct 2014, 07:36
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Is this a crisis ? Most club Cessna 152's have at least one fuel measuring tool in the tank and they don't seem to fall out of the sky !
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Old 27th Oct 2014, 09:08
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I helped a friend remove the tank from his Jodel yesterday. He appeared quite surprised when I shook it and it rattled. Most older aircraft have "stuff" in the tank. My old AA5 had quite a bit in one side and nothing in the other. A check in the paperwork showed it had had a seep and been removed not long before I got it.

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Old 27th Oct 2014, 10:25
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first question is does it need to be removed?

If the outlet pipe stands up say 1 cm and has a mesh covering, I would suggest it is safe to leave it.
Otherwise I would say it should be removed as a low tank could pull the pencil in.

In theory it should float, but once fully saturated, it may lose most of its floatation ability.

Seems to me one could be lucky with the floatation method mentioned above. I would be cautious of expecting success.
Otherwise drain the tank, vent it as best one can and use a borascope/ mirror and claw.
A further alternative is to slide the tank out of the wing. This is not such a big job as one may think.

I would avoid switching the lights on or off while in the presence of fuel or fuel vapours (the switch spark is the danger).

Good luck

Flyme
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Old 27th Oct 2014, 10:55
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first question is does it need to be removed?

If the outlet pipe stands up say 1 cm and has a mesh covering, I would suggest it is safe to leave it.
There is a lot of practical truth in this. This type of "in the tank" thinking stretches our tolerance of the relationship between "safe" and "airworthy".

Would I fly a plane home with a pencil in the fuel tank? Yup, without a worry in the world. Would I try to get it passed during a scheduled inspection that way? Nope, it just would not pass!

Yes, I too, have found some rather surprising things in fuel tanks, and between them and structure. The plane had flown safely up to that point, but not "airworthy".
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Old 27th Oct 2014, 11:03
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If you can't find a torch to look for the pencil you could use a lighter or a match.
The Aerial Arts Chaser POH included this: "WARNING - Smoking can be bad for your health - Do not smoke while refuelling."
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Old 27th Oct 2014, 11:19
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Extract from AAIB Special bulletin 01/2008 G-YMMM incident:-

In the area of the left main tank water scavenge pump inlet:A piece of black plastic tape (3M 226HD) approximately 52 mm x 50 mm (2 inch tape). The tape had a number of circular marks similar in size and layout to the holes on the water scavenge pump inlet. It was likely that the tape was left in the tank during the construction of the aircraft.
A piece of brown paper the same shape and size as the black plastic tape. The paper had two circular marks similar to those on the plastic tape and is believed to be the adhesive backing for this piece of tape.A piece of yellow plastic approximately 10 mm x 12 mm. The plastic was similar in appearance to electrical cable identity tape.


A small piece of fabric/paper was found in the inlet gate/guillotine valve of the right centre OJ pump.

flyme

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Old 27th Oct 2014, 11:42
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Does a pencil float on avgas? Anyone tried it?
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Old 27th Oct 2014, 13:26
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Does a pencil float on avgas?
Good question.

According to How pencil is made - material, manufacture, making, history, used, processing, steps, product, machine, Raw Materials, The Manufacturing Process of pencil, Colored pencils, Quaility Control, pencils are typically made from Cedar wood. Dry Cedar has a SG of .38 (Specific Gravity Of Wood Table).

The SG of the graphite core is less readily available, but is apparently between 1.9 and 2.3. (Graphite: The mineral Graphite information and pictures)

The thickness of a pencil is 6mm (radius 3mm) so by a first approximation the cut-through area is 3^2*pi = 28.3 mm2. The lead core has a diameter of 2mm (radius 1mm) so that area is 3.14 mm2.

This means the worst-case SG of the pencil is approximately ( (.38 * (28.3-3.14)) + (2.3 * 3.14) ) / 28.3 = .59. The SG of avgas is .72 so the pencil should float. But this does not take into account the weight of the varnish and a possible eraser. Or what happens when the wood soaks up the avgas, or the effects of a potential chemical reaction between the graphite core and the avgas. Or the fact that if you sharpen the pencil, you remove relatively more wood than graphite core so the SG goes up.

So I would not automatically assume a pencil floats in avgas.
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Old 27th Oct 2014, 14:17
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you could drop one in a pa38 fuel tank and see.
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Old 27th Oct 2014, 14:21
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Believe it or not, there is a Pencil Museum in the UK, somewhere around the Lake District as I recall.

If you do manage to fish the pencil out, I suspect it could become the museum's star attraction
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Old 27th Oct 2014, 14:33
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I have been to said Museum its not bad actually.
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Old 27th Oct 2014, 14:51
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"Does a pencil float on avgas? "

I think we know a man who will have an answer to that

Rod1
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Old 27th Oct 2014, 19:09
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Will a pencil break down over time ? Bung up any gauze fuel pipe filters or even block a jet , I'd fly it home but I'd want it out ASAP , heaven forbid anything happend to the aircraft and the AAIB found it in the tank , the insurance company would love that " any excuse not to pay"
Austerwobbler
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Old 27th Oct 2014, 19:13
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Trouble us that the paint will flake off.
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Old 27th Oct 2014, 21:27
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The engineers extricated said pencil today - not sure how but will ask them - they didn't take long!

Thanks for all the help and suggestion.
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Old 27th Oct 2014, 21:39
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Hurrah!

(But do tell, did it float?)
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Old 27th Oct 2014, 21:43
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So you got your fuel draw back









I'll get my coat.....
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