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Hi All,
I'm in the UK doing the Annual Inspection, and here we don't have an experimental category, instead we have to comply with "an known and accepted international design standard"
In practice that means JAR or FAR.
So I'm looking for the canonical reference which states that alum AN fittings cannot be used in the engine bay, as I have "been told" by an inspector that they should all be steel.
I see that FAR23.1191(1) refers to firewall components being able to resist 2,000f but that specifically addresses the firewall, and makes no reference to the myriad components in the engine bay far away from the firewall.
I also see that AC42.13-1B 7.64(f) makes reference to the use of fiber or nylon self locking nuts not to be used when temps >250F, but makes no mention of AN fittings.
So I haven't found anything prescriptive about all the AN fittings in the fuel and oil lines in the engine bay.
I realise that in high vibration locations steel may be a better choice, but in more benign use, alum is both lighter and cheaper and easier to find.
I recall that we had this discussion some while back but can't find the thread - I think Marc Zeitlin had some aposite comments - maybe someone else can turn up a regulation that I can use to take down my inspector with, as changing all those fittings is a lot of time and money - even if I can find them.
Maybe I should just paint all my blue fittings black and say they're steel..... :^)
best,
Bill Allen
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On 6/4/2022 10:22 AM, Bill Allen wrote: Hi All,
I'm in the UK doing the Annual Inspection, and here we don't have an
experimental category, instead we have to comply with "an known and accepted
international design standard"
In practice that means JAR or FAR.
So I'm looking for the canonical reference which states that alum AN fittings
cannot be used in the engine bay, as I have "been told" by an inspector that
they should all be steel. Well, your engine has a bit of aluminum in it ... I see that FAR23.1191(1) refers to firewall components being able to resist
2,000f but that specifically addresses the firewall, and makes no reference to
the myriad components in the engine bay far away from the firewall.
I also see that AC42.13-1B 7.64(f) makes reference to the use of fiber or nylon
self locking nuts not to be used when temps >250F, but makes no mention of AN
fittings. The fiber can get hot, melt or soften, and the locking effect goes away. So I haven't found anything prescriptive about all the AN fittings in the fuel
and oil lines in the engine bay.
I realise that in high vibration locations steel may be a better choice, but in
more benign use, alum is both lighter and cheaper and easier to find. Correct, steel will most likely take more stress and vibration than aluminum. I recall that we had this discussion some while back but can't find the thread -
I think Marc Zeitlin had some aposite comments - maybe someone else can turn up
a regulation that I can use to take down my inspector with, as changing all
those fittings is a lot of time and money - even if I can find them.
Maybe I should just paint all my blue fittings black and say they're steel..... :^) You're the one in the front seat ... -- David Froble Tel: 724-529-0450 Dave Froble Enterprises, Inc. E-Mail: davef@... DFE Ultralights, Inc. 170 Grimplin Road Vanderbilt, PA 15486
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Bill,
Burt Rutan changed all fittings in Engine compartment must be steel. Published in CPS long ago. I used to check CP changes on Marc Broom website but since Marc passed away I cannot find his website anymore.
On Jun 4, 2022, at 9:22 AM, Bill Allen <billallensworld@...> wrote:
Hi All,
I'm in the UK doing the Annual Inspection, and here we don't have an experimental category, instead we have to comply with "an known and accepted international design standard"
In practice that means JAR or FAR.
So I'm looking for the canonical reference which states that alum AN fittings cannot be used in the engine bay, as I have "been told" by an inspector that they should all be steel.
I see that FAR23.1191(1) refers to firewall components being able to resist 2,000f but that specifically addresses the firewall, and makes no reference to the myriad components in the engine bay far away from the firewall.
I also see that AC42.13-1B 7.64(f) makes reference to the use of fiber or nylon self locking nuts not to be used when temps >250F, but makes no mention of AN fittings.
So I haven't found anything prescriptive about all the AN fittings in the fuel and oil lines in the engine bay.
I realise that in high vibration locations steel may be a better choice, but in more benign use, alum is both lighter and cheaper and easier to find.
I recall that we had this discussion some while back but can't find the thread - I think Marc Zeitlin had some aposite comments - maybe someone else can turn up a regulation that I can use to take down my inspector with, as changing all those fittings is a lot of time and money - even if I can find them.
Maybe I should just paint all my blue fittings black and say they're steel..... :^)
best,
Bill Allen
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As an A&P working for over 45 years, all fittings in the engine had to be steel. It was required because aluminum fittings fatigued and cracked from vibration. That was my understanding
On Jun 4, 2022, at 3:07 PM, Steve Beert <stephen.beert@...> wrote:
Bill,
Burt Rutan changed all fittings in Engine compartment must be steel. Published in CPS long ago. I used to check CP changes on Marc Broom website but since Marc passed away I cannot find his website anymore.
Steve On Jun 4, 2022, at 9:22 AM, Bill Allen <billallensworld@...> wrote:
Hi All,
I'm in the UK doing the Annual Inspection, and here we don't have an experimental category, instead we have to comply with "an known and accepted international design standard"
In practice that means JAR or FAR.
So I'm looking for the canonical reference which states that alum AN fittings cannot be used in the engine bay, as I have "been told" by an inspector that they should all be steel.
I see that FAR23.1191(1) refers to firewall components being able to resist 2,000f but that specifically addresses the firewall, and makes no reference to the myriad components in the engine bay far away from the firewall.
I also see that AC42.13-1B 7.64(f) makes reference to the use of fiber or nylon self locking nuts not to be used when temps >250F, but makes no mention of AN fittings.
So I haven't found anything prescriptive about all the AN fittings in the fuel and oil lines in the engine bay.
I realise that in high vibration locations steel may be a better choice, but in more benign use, alum is both lighter and cheaper and easier to find.
I recall that we had this discussion some while back but can't find the thread - I think Marc Zeitlin had some aposite comments - maybe someone else can turn up a regulation that I can use to take down my inspector with, as changing all those fittings is a lot of time and money - even if I can find them.
Maybe I should just paint all my blue fittings black and say they're steel..... :^)
best,
Bill Allen
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Bill.... paint them black LOL. That would work.
Hi All,
I'm in the UK doing the Annual Inspection, and here we don't have an experimental category, instead we have to comply with "an known and accepted international design standard"
In practice that means JAR or FAR.
So I'm looking for the canonical reference which states that alum AN fittings cannot be used in the engine bay, as I have "been told" by an inspector that they should all be steel.
I see that FAR23.1191(1) refers to firewall components being able to resist 2,000f but that specifically addresses the firewall, and makes no reference to the myriad components in the engine bay far away from the firewall.
I also see that AC42.13-1B 7.64(f) makes reference to the use of fiber or nylon self locking nuts not to be used when temps >250F, but makes no mention of AN fittings.
So I haven't found anything prescriptive about all the AN fittings in the fuel and oil lines in the engine bay.
I realise that in high vibration locations steel may be a better choice, but in more benign use, alum is both lighter and cheaper and easier to find.
I recall that we had this discussion some while back but can't find the thread - I think Marc Zeitlin had some aposite comments - maybe someone else can turn up a regulation that I can use to take down my inspector with, as changing all those fittings is a lot of time and money - even if I can find them.
Maybe I should just paint all my blue fittings black and say they're steel..... :^)
best,
Bill Allen
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