KR> broken fuel line and lessons learned

[John Martindale]

Hi Larry

The PMA nipple where that line attaches to the engine block should have a
very small orifice (pin holes size) to minimise oil loss in the event of a
breakage you describe. 

The theory is that the pressure, being equal in a system, is still
transmitted.  Trouble is when the oil is cold this can take some time and
your gauge is slow to register on start up when you really want to know
quickly that pressure is there. Sometimes a light machine oil is put in the
tube after the hole and provided it can't run out, that is, the tube goes
downhill to the gauge, the time lag can be reduced. 

Sometimes the orifice nipple is mistakenly replaced with a normal nipple and
then oil just pisses out.. head for the nearest strip quick :-). 


John Martindale
29 Jane Circuit
Toormina NSW 2452
Australia

ph:61 2 6658 4767
m:0403 432179
email:john_martindale at bigpond.com
web site: http://john-martindale-kr2.zxq.net
-Original Message-
From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Larry Howell
Sent: Friday, 26 July 2013 2:28 PM
To: KRnet
Subject: Re: KR> broken fuel line and lessons learned




"Jeff Scott"  wrote:

> I thought I would look that up in AC43.13.  It says surprisingly little
about the fuel lines them selves, so now I'm wondering where it is that I
learned that so many years ago?  
> 
> 


> 
> I remember a small copper line from my engine going to the oil pressure
gauge in my FAA certified factory built Mooney breaking and spewing oil onto
a friends legs just before we departed my airport years ago that caused us
to miss a day of flying. If I'm not mistaken I think I remember similar fuel
pressure lines in some of the other factory planes I have owned! I might be
mistaken about the fuel lines though.

> Larry H


>  

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KR> broken fuel line and lessons learned

[brian.kraut at eamanufacturing.com]

I just put on the new hose and I did use a small orifice in the fitting.
 Vans sells one with a .040" orifice for both oil and fuel pressure use.
 It is just a modified AN fitting with an aluminum plug with a small
hole in it.  I just finished making one on my lathe.  For fuel pressure
it is still very fast reacting.


 Original Message 
Subject: Re: KR> broken fuel line and lessons learned
From: "John Martindale" 
List-Post: krnet@list.krnet.org
Date: Thu, July 25, 2013 11:13 pm
To: "'KRnet'" 

Hi Larry

The PMA nipple where that line attaches to the engine block should have
a
very small orifice (pin holes size) to minimise oil loss in the event of
a
breakage you describe. 

The theory is that the pressure, being equal in a system, is still
transmitted. Trouble is when the oil is cold this can take some time and
your gauge is slow to register on start up when you really want to know
quickly that pressure is there. Sometimes a light machine oil is put in
the
tube after the hole and provided it can't run out, that is, the tube
goes
downhill to the gauge, the time lag can be reduced. 

Sometimes the orifice nipple is mistakenly replaced with a normal nipple
and
then oil just pisses out.. head for the nearest strip quick :-). 


John Martindale
29 Jane Circuit
Toormina NSW 2452
Australia

ph:61 2 6658 4767
m:0403 432179
email:john_martindale at bigpond.com
web site: http://john-martindale-kr2.zxq.net
-Original Message-
From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Larry
Howell
Sent: Friday, 26 July 2013 2:28 PM
To: KRnet
Subject: Re: KR> broken fuel line and lessons learned




"Jeff Scott"  wrote:

> I thought I would look that up in AC43.13. It says surprisingly little
about the fuel lines them selves, so now I'm wondering where it is that
I
learned that so many years ago? 
> 
> 


> 
> I remember a small copper line from my engine going to the oil pressure
gauge in my FAA certified factory built Mooney breaking and spewing oil
onto
a friends legs just before we departed my airport years ago that caused
us
to miss a day of flying. If I'm not mistaken I think I remember similar
fuel
pressure lines in some of the other factory planes I have owned! I might
be
mistaken about the fuel lines though.

> Larry H


> 

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-
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2013.0.3349 / Virus Database: 3209/6521 - Release Date:
07/25/13


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KR> broken fuel line and lessons learned

[Larry Howell]

"Jeff Scott"  wrote:

> I thought I would look that up in AC43.13.  It says surprisingly little about 
> the fuel lines them selves, so now I'm wondering where it is that I learned 
> that so many years ago?  
> 
> 


> 
> I remember a small copper line from my engine going to the oil pressure gauge 
> in my FAA certified factory built Mooney breaking and spewing oil onto a 
> friends legs just before we departed my airport years ago that caused us to 
> miss a day of flying. If I'm not mistaken I think I remember similar fuel 
> pressure lines in some of the other factory planes I have owned! I might be 
> mistaken about the fuel lines though.

> Larry H


>  

KR> broken fuel line and lessons learned

[Jeff Scott]

Good write up Brian. ?I'm sure you probably already know this, but copper fuel 
lines are typically not an OK thing to do. ?The only exception to that is the 
little 1/8" primer lines as they only have fuel pressurized in them momentarily 
when you stroke the primer (or only when priming if you have an electric 
primer). ?As you found this week, even with loops in them, copper lines are 
prone to breakage due to vibration and work hardening from the vibration. ?The 
rule of thumb here is that you don't use a copper line where it always has 
either fuel flow through it, or fuel pressure that could become a flow should 
the line break. ?

I thought I would look that up in AC43.13. ?It says surprisingly little about 
the fuel lines them selves, so now I'm wondering where it is that I learned 
that so many years ago? ?However, I would count this as a very valuable lesson 
to builders, as we could very well have been reading about Brian disappearing 
in a ball of flame.

-Jeff Scott
Los Alamos, NM




> - Original Message -
> From: brian.kraut at eamanufacturing.com
> Sent: 07/24/13 01:27 PM
> To: KRnet
> Subject: Re: KR> broken fuel line and lessons learned
> 
> Hopefully will actually work this time.
> 
> 
> Just returned from a flight to Mobile yesterday and back near
> Jacksonville, FL today. Was going to make my normal stop about 20 miles
> south of the airpark for fuel, but after my decent I found that it was
> broken at 3,000' and a thin scattered layer around 600' after showers
> just moved through the area. I made a non-eventful landing with the
> normal electric boost pump on in downwind and turned off just after
> landing. During taxii back I noticed a fuel flow going way up and
> stopping about 20 GPM. Made a quick taxii for the hanger and noticed a
> slight fuel smell so shut down quickly just before the hanger. After
> pulling it inside starter to take the cowl off and noticed a small fuel
> puddle under the plane. The builder of this plan was smart to put about
> a 1/8" drain hole in the low part of the cowl to keep any leaking fuel
> from pooling in the bottom of the cowl and I strongly recommend that
> everyone do that.
> 
> After I got the cowl off I noticed that the copper fuel line that runs
> from a fitting on the mechanical fuel pump to the firewall mounted fuel
> pressure sender was broken off right where it comes out of the AN flare
> fitting from the mechanical fuel pump. A quick blip on the electric
> boost pump that is right before the mechanical pump confirmed my fear
> that it shoots out of the small hole inside the copper line like a
> squirt gun and much of it winds up spraying on the exhaust pipe. That
> was enough to make me cringe.
> 
> I will admit that I did not look at the fuel pressure gauge during my
> pre-landing check. Skating around the low clouds on downwind had me
> looking outside which was probably the best place for me to be looking
> at the time. Not sure if I would have seen the lack of pressure on the
> gauge because I don't know if the break occured when I turned on the
> boost pump or maybe right as I landed or during taxii.
> 
> It was a fairly smooth landing so I really don't that that small bump is
> what broke the line. I generally don't notice much of an increase in
> fuel pressure with the electric pump on, but I do see an increase on the
> flow meter from the pulsing of the pump. I do regularly check for fuel
> leaks in fuel system by turning on the boost pump while the engine is
> not running and confirming that it holds pressure for several minutes
> with no fuel flow showing on the meter after the pumps is shut off. I
> did that just a few weeks ago and thoroughly checked for leaks with the
> electric pump on during the condition inspection, so might have been a
> small crack leaking a bit, but not not for very long. Anyway, I am
> always looking at my fuel flow and it did not go up until just after
> landing.
> 
> I am very thankful that the line did not break and start a fire in
> flight. Nothing like a small fuel line becoming a spraying blowtorch
> with low ceilings and visibility.
> 
> 
> Several lessons learned.
> 
> The solid copper line did have several loops in it to make it flexible,
> but no more solid lines in the pressurized section of the fuel lines for
> me. It will be replaced with a flexible stainless armored aircraft fuel
> line before the next flight with fire braid over it. All my other fuel
> lines are this way with the exception of the aluminum primer line, but
> that line is not under constant pressure. If I built this plane it
> would have been that way from the start because I would have thought
> about it when I installed it. Being as it was already there I never
> really thought about it.

KR> broken fuel line and lessons learned

[Robert Boyd]

Don't fly when you're passing gas!!!



On Wed, Jul 24, 2013 at 1:56 PM,  wrote:

> So, what is the lesson?  Don't have a broken fuel line?
>
> On Wednesday, July 24, 2013 1:28 PM, brian.kraut at eamanufacturing.comwrote:
>
> =
>
>
>
>
> ___
> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search.
> To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org
> please see other KRnet info at http://www.krnet.org/info.html
> see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change
> options
>

KR> broken fuel line and lessons learned

[danrh at windstream.net]

So, what is the lesson?  Don't have a broken fuel line?

On Wednesday, July 24, 2013 1:28 PM, brian.kraut at eamanufacturing.com wrote: 

=

KR> broken fuel line and lessons learned

[brian.kraut at eamanufacturing.com]

Hopefully will actually work this time.


Just returned from a flight to Mobile yesterday and back near
Jacksonville, FL today.  Was going to make my normal stop about 20 miles
south of the airpark for fuel, but after my decent I found that it was
broken at 3,000' and a thin scattered layer around 600' after showers
just moved through the area.  I made a non-eventful landing with the
normal electric boost pump on in downwind and turned off just after
landing.  During taxii back I noticed a fuel flow going way up and
stopping about 20 GPM.  Made a quick taxii for the hanger and noticed a
slight fuel smell so shut down quickly just before the hanger.  After
pulling it inside starter to take the cowl off and noticed a small fuel
puddle under the plane.  The builder of this plan was smart to put about
a 1/8" drain hole in the low part of the cowl to keep any leaking fuel
from pooling in the bottom of the cowl and I strongly recommend that
everyone do that.

After I got the cowl off I noticed that the copper fuel line that runs
from a fitting on the mechanical fuel pump to the firewall mounted fuel
pressure sender was broken off right where it comes out of the AN flare
fitting from the mechanical fuel pump.  A quick blip on the electric
boost pump that is right before the mechanical pump confirmed my fear
that it shoots out of the small hole inside the copper line like a
squirt gun and much of it winds up spraying on the exhaust pipe.  That
was enough to make me cringe.

I will admit that I did not look at the fuel pressure gauge during my
pre-landing check.  Skating around the low clouds on downwind had me
looking outside which was probably the best place for me to be looking
at the time.  Not sure if I would have seen the lack of pressure on the
gauge because I don't know if the break occured when I turned on the
boost pump or maybe right as I landed or during taxii.

It was a fairly smooth landing so I really don't that that small bump is
what broke the line.  I generally don't notice much of an increase in
fuel pressure with the electric pump on, but I do see an increase on the
flow meter from the pulsing of the pump.  I do regularly check for fuel
leaks in fuel system by turning on the boost pump while the engine is
not running and confirming that it holds pressure for several minutes
with no fuel flow showing on the meter after the pumps is shut off.  I
did that just a few weeks ago and thoroughly checked for leaks with the
electric pump on during the condition inspection, so might have been a
small crack leaking a bit, but not not for very long.  Anyway, I am
always looking at my fuel flow and it did not go up until just after
landing.

I am very thankful that the line did not break and start a fire in
flight.  Nothing like a small fuel line becoming a spraying blowtorch
with low ceilings and visibility.


Several lessons learned.

The solid copper line did have several loops in it to make it flexible,
but no more solid lines in the pressurized section of the fuel lines for
me.  It will be replaced with a flexible stainless armored aircraft fuel
line before the next flight with fire braid over it.  All my other fuel
lines are this way with the exception of the aluminum primer line, but
that line is not under constant pressure.  If I built this plane it
would have been that way from the start because I would have thought
about it when I installed it.  Being as it was already there I never
really thought about it.

I can't reach my fuel shutoff in flight without taking off the seatbelt.
 I had been planning on adding some type of remote actuation to the
lever.  That will be done before I leave for Oshkosh.  Been in a burning
aircraft on the ground before.  Don't want to be in a burning aircraft
in the air(nor on the ground again, but certainly not in the air).

Next time I notice a weird indication I will take action immediately.  I
should have shut down the engine and turned off the fuel as soon as I
noticed the high flow rate.  Taxiing back to the hanger thinking "hmmm,
flow meter acting funny again, but just flew 400 miles so plane must be
fine" was not the right move, especially when it would have been very
easy for me to walk a thousand feet to my house and tow the plane back
with my truck.

Hopefully others can learn something from this and prevent a story
without a happy ending.

KR> Broken Fuel line and lessons learned

[brian.kraut at eamanufacturing.com]

KR> broken fuel line and lessons learned

[brian.kraut at eamanufacturing.com]

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