cracking noise during fueling

blueskyMD

blueskyMD

Pre-takeoff checklist
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Mar 26, 2015
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Bigfoot297
When I fuel the airplane ( Piper Lance II with 2 interconnected tanks on each side ) especially if the tanks ( left side only ) is almost empty , I start hearing cracking noise as tanks starts filling half way. Noise is not really loud its just faint crackle but you can hear it. This has been happening for a quite a while at least 5 + years that I remember. Now before there are calls to ground the airplane , 2 mechanics looked at the spar and other wing structures and said there is nothing to worry about. Just curious if anyone else out there had this kind of issue.
 
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are you sure you're not just hearing the hot fuel in the lines making funny noises?
 
Just a bit of static electricity... no worries, generally there’s not enough O2 to support combustion with all those gas fumes.

...just joking, no idea.


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Could be the gear struts compressing as the fuel load increases. The struts may be experiencing a condition known as “sticktion”, where the seals tend to hang up a tiny bit before they move. The tiny movement as the seals move in increments rather than smoothly is transmitted through the airframe. That’s probably what you’re hearing.
 
Brad Smith said:
Could be the gear struts compressing as the fuel load increases. The struts may be experiencing a condition known as “sticktion”, where the seals tend to hang up a tiny bit before they move. The tiny movement as the seals move in increments rather than smoothly is transmitted through the airframe. That’s probably what you’re hearing.
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I was going to say the struts too. Mine do it as I fill the tanks.
 
Riveted aluminum panels creak and pop as weight is added. My Cessa has fuel bladders and does the same thing.
 
Fuel truck is loud enough I don't think I could hear anything like that..
 
AKBill said:
Fuel truck is loud enough I don't think I could hear anything like that..
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That might be the reason I don't hear it on right side because I am close to the pump while filling right side
 
If you have wet wings it could also be movement from adding cold fuel into a warm wing.
 
Brad Smith said:
Could be the gear struts compressing as the fuel load increases. The struts may be experiencing a condition known as “sticktion”, where the seals tend to hang up a tiny bit before they move. The tiny movement as the seals move in increments rather than smoothly is transmitted through the airframe. That’s probably what you’re hearing.
Click to expand...

This is what I was thinking also. One of the club's Cherokees is so bad the left strut will stay at full extension, even after fueling. I've sat and watched a crew pre-flight and climb in. Then, they look surprised when the strut collapses to its normal extension. I wonder if they even noticed how much higher the left wing was on preflight.

Almost every Piper low wing I see has nasty struts. Wipe those things down with a lint free cloth and some Mil-H-5606 (the shiny part and any exposed seals).
 
That's the lead in the fuel hitting the bottom of the tank. Don't sweat it.
 
I don't understand..... the fuel guy fills it. I'm in the FBO eating cookies and telling the desk girl about my "to mins" approach and how I punched through a nasty storm with ADSB on board. I've never heard my Lance make any noise like that.
 
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