Interesting Ice formation

[Mark89114]

I was coming out of Chicago the other day and temps were in the high single digits in Celcius and after I got through all of the visible moisture I looked out at my right wing and saw this white looking stuff building up behind the apparently now leaking fuel tank cap.  Confounded me for a while as I was 100% sure it wasn't there when I left and then I looked back and it was gone.  Best I can figure is the moisture coming off the gas cap combined with the evaporation of the fuel dropped the temperature locally enough to freeze what water was there.  I just thought it was interesting.

Now the fuel tank leaking is a new phenomenon, the line guys did really fill it up and I was able to push the cap down just a tiny smidge after I landed.  That was on me, as I did visually check the quantity.  I looked the gasket over and nothing looked odd, will just continue to monitor and see if this occurs again.  Any advice appreciated.  I did lose a couple of gallons I think.  

 

[flight2000]

It could be just the picture, but the cap looks like it's canted forward slightly, meaning it's not seated properly.  That would cause the gas to flow out exactly where the ice formed.  Been there, done that....

Brian

[Bryan]

"Been there, done that..."  too!

However, if the cap is sealed, could it be condensation, or moisture that collected inside the top of the fuel cap and got sucked out and down the wing.  Based on the picture, it does look like it came from the fuel cap but no hint of Blue from 100LL.

[kmyfm20s]

Could just been from water puddle up in the fuel cap recess. As you picked up airspeed it blew backward and froze. Just a thought?

[MARZ]

Any fuel Mist at Mooney speed should evaporate the liquid (fuel) - that evaporation would lower the ambient temp - think MEK on your shop rag - that lower ambient temp would be the tipping point of actually freezing the moisture in the air.....

just some thoughts... 

[thinwing]

Plus the canted cab created a burble so as the escaping fuel vaporized ,lowered temp below dew point ,ice accumulated in the shadow of that burble

[Mark89114]

Again it was just a random event I thought was reasonably interesting.

Good catch on the fuel cap.....it was leaking a bit, I will make sure it is properly installed next time.  Makes sense as I have had no issues with leakage in the past.

Fly safe everybody.

 

[Yetti]

If it was not hard to close and you can cant it like that without hammering down the lever, then it probably is not adjusted properly or your big oring is beyond its useful life.

[carusoam]

That sure is an interesting ice formation...

The cap is in need of attention... it is not flush like it supposed to be...

The ice formation... Most likely caused by the cap interfering with the airflow locally... breaking up the protective boundary layer at that spot...

as far as temperature goes... so much air going over the wing getting it’s pressure dropped does two things...

The low pressure environment ...

• Drops moisture out of solution... allowing it to freeze...
• Drops the temperature into the freezing range...

If fuel exited the tank... there would be a significant amount of blue to accompany that...

If fuel is evaporating in the tank, the blue is being left behind, concentrating in the rest of the fuel...

If your orings hold water above the caps or it is raining...and the caps aren’t sealing... you may see bubbles forming showing how much air is leaking out...

 

To get fuel evaporation to drop that much moisture and freezing... think carb ice... that would be a lot of fuel dissapearing....

Great pics, mike!

Best regards,

-a-