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Posted

Hi guys,

This may be one of those "if you're asking it, then you already know that it's the hard way" questions, but I'll give it a shot..

Just put in G5-HSI. Haven't hooked it up to pitot static. My mechanic says either way is up to me. Now, if I do that and do a leak test on my pitot static lines, then is my 24 monthly test void? Or do the previously tested equipment still certified? You know, if the lines do not leak, pretty much nothing has changed for the pre-G5hsi-install equipment.. 

Please don't answer "just get it recerted. Not everyone does it and wife said no more plane time because I've been away from home too many evenings...

Thanks.

Posted (edited)

I’ve never heard of anything like this . I’m not sure why the Pitot static Cert would be void. The newly installed component must certainly be ops checked within the system.  Why would that void the previous certification? Sort of like wondering if your annual inspection is void because you install a new prop governor

Edited by Shadrach
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Posted

Do you intend to operate under IFR?  If so, I think the 91.411 requirement is pretty clear:  Per 91.411(2):

Except for the use of system drain and alternate static pressure valves, following any opening and closing of the static pressure system, that system has been tested and inspected and found to comply with paragraph (a), appendix E, of part 43 of this chapter;

Connecting a G5 to the static system certainly involves opening the static pressure system.  If you want to be strictly legal, a re-test is required.

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Posted
7 minutes ago, Vance Harral said:

following any opening and closing of the static pressure system,

There.... Thanks a lot man. I was hoping for a weasel-out but I guess there's none.  Alright, I have until next cert to decide whether I want it hooked up ...

Thanks again.

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Posted
13 minutes ago, Vance Harral said:

Do you intend to operate under IFR?  If so, I think the

15 minutes ago, FlyingDude said:

There.... Thanks a lot man. I was hoping for a weasel-out but I guess there's none.  Alright, I have until next cert to decide whether I want it hooked up ...

Thanks again.

requirement is pretty clear:  Per 91.411(2):

Except for the use of system drain and alternate static pressure valves, following any opening and closing of the static pressure system, that system has been tested and inspected and found to comply with paragraph (a), appendix E, of part 43 of this chapter;

Connecting a G5 to the static system certainly involves opening the static pressure system.  If you want to be strictly legal, a re-test is required.

Per the reg it DOES NOT void your Cert. It simply requires the integrity of the system be tested. Appendix E paragraph a is below. Anyone who believes what is outlined below constitutes an IFR certification has never participated in one.

a) Static pressure system: 

(1) Ensure freedom from entrapped moisture and restrictions. 

(2) Perform a proof test to demonstrate the integrity of the static pressure system in a manner acceptable to the Administrator. For airplanes certificated under part 25 of this chapter, determine that leakage is within the tolerances established by § 25.1325.

(3) Determine that the static port heater, if installed, is operative. 

(4) Ensure that no alterations or deformations of the airframe surface have been made that would affect the relationship between air pressure in the static pressure system and true ambient static air pressure for any flight condition.

 

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Posted
1 hour ago, Shadrach said:

Per the reg it DOES NOT void your Cert.

OK, I'll play.  If your point is that opening the static system doesn't void the altimeter or transponder checks described in FAR 43 Appendix E paragraphs (b) and (c), sure.  But it does require the static system checks described in paragraph (a), particularly clause (2).  The sub-clause about part 25 certification doesn't apply to Mooneys, but one must "Perform a proof test to demonstrate the integrity of the static pressure system in a manner acceptable to the Administrator".

I suppose one can envision all kinds of methods that might accomplish this, but the FAA literature - including specifically AC 43-6D - makes reference to the kind of equipment and trained personnel that only repair shops which provide full 91.411 certification have on hand.  If you are proposing there is some other "proof test", that your are confident is "acceptable to the Administrator", which requires only equipment and training the average A&P has in their shop, I'm all ears.

My basic point is, you can't just install a G5 or GI-275 and say, "the installer was careful when they tightened up the static system connections, and that's good enough".  The static system must be tested, using equipment designed to do so.

Posted

My understanding for 91.411 is that the full 24-month IFR certification must be performed by a repair station. Simply opening the static system requires a leak test that can be performed by an A&P. 

Skip

  • Like 4
Posted

Simple question…

If you fly in IMC… how comfortable are you with a simple leak test?

I’d be so inclined… that my leak test would include accuracy of the instrument readings…. Which is pretty much checking the calibration as if it were a pitot static system test…

Possibly saving the extra time required to adjust anything… unless the readings are off.

 

Wow, that probably didn’t help the conversation….  :)

PP thoughts only, my IR isn’t current…

Best regards,

-a- 

 

Posted (edited)
20 hours ago, Vance Harral said:

OK, I'll play.  If your point is that opening the static system doesn't void the altimeter or transponder checks described in FAR 43 Appendix E paragraphs (b) and (c), sure.  But it does require the static system checks described in paragraph (a), particularly clause (2).  The sub-clause about part 25 certification doesn't apply to Mooneys, but one must "Perform a proof test to demonstrate the integrity of the static pressure system in a manner acceptable to the Administrator".

I suppose one can envision all kinds of methods that might accomplish this, but the FAA literature - including specifically AC 43-6D - makes reference to the kind of equipment and trained personnel that only repair shops which provide full 91.411 certification have on hand.  If you are proposing there is some other "proof test", that your are confident is "acceptable to the Administrator", which requires only equipment and training the average A&P has in their shop, I'm all ears.

My basic point is, you can't just install a G5 or GI-275 and say, "the installer was careful when they tightened up the static system connections, and that's good enough".  The static system must be tested, using equipment designed to do so.

I'm not playing anything nor am I proposing some type of backwoods improvised testing method.   I've been present for every biannual IFR certification done on my bird over the last 15 years.  I know what's involved, I have been through failures, repairs and the rectification..  Satisfying the requirements of paragraph (a) in appendix E is not a recertification, it is not as involved as a certification nor does it cover all of the same components. If I gave the impression that I was suggesting what you're ascribing above, then forgive my clumsy wording. Nevertheless, the fact remains that the IFR certification is not voided. The OP specifically asked (typo notwithstanding) "Or do the previously tested equipment still certified?" I interpreted that to mean is the previously tested equipment still certified.  The answer to which is YES if it is still within the 24 month time period. 

Referencing the the Table A-3 in AC 43-6D where do you think plumbing the G5 into the system best fits?  While the G5 is a certified primary Attitude indicator it is not a certified as a primary Altimeter or ASI.  The FAA defines Pilot Reference Altimeter as the altimeter normally used to maintain flight altitude.  Are you suggesting that is something other than the primary Altimeter?

You've referenced the right regs and literature but it does not say what you've told the OP that it says. 

AC43-6D.jpg.bf555988243ea775c978cd052eca0690.jpg

 

Altimeter Other than pilot reference. 1. Field elevation verification. 2. Static leak test.

Edited by Shadrach
Posted (edited)
17 hours ago, carusoam said:

Simple question…

If you fly in IMC… how comfortable are you with a simple leak test?

I’d be so inclined… that my leak test would include accuracy of the instrument readings…. Which is pretty much checking the calibration as if it were a pitot static system test…

Possibly saving the extra time required to adjust anything… unless the readings are off.

 

Wow, that probably didn’t help the conversation….  :)

PP thoughts only, my IR isn’t current…

Best regards,

-a- 

 

Is there something wrong with a simple static leak test? None of the other components have been disturbed.  What exactly do you think happens to the other components when a new component is added?  Perhaps they get jealous and and refuse play on the team?

Edited by Shadrach
Posted
1 minute ago, Shadrach said:

Is there something wrong with a simple static leak test? None of the other components have been disturbed?  What exactly do you think happens to the other components when a new component is added?  Perhaps they get jealous and and refuse play on the team?

Thanks Ross.
 

My guess… (because it’s way outside my skill set)

1) I would be adding a line into both the pitot and the static system…

2) Possibly with a bad new fitting with a slow leak… crummy hardware, or improper assembly, or random mismatch of fitting parts…

3) Would the simple leak test find a small leak that would be a challenge to the airspeed indicator or the altimeter?

4) Looks like if everything goes to plan… the simple leak test works…

5) I’ve entered the too many what-ifs zone here…

6) If I flew in IFC…. I would want a pretty strong leak test… to show my new parts on the system haven’t caused a surprise in the system. :)
 

7) It’s possible the ordinary leak tests actually do all this… and I’m blissfully unaware.

Best regards,

-a-

Posted
3 minutes ago, carusoam said:

Thanks Ross.
 

My guess… (because it’s way outside my skill set)

1) I would be adding a line into both the pitot and the static system…

2) Possibly with a bad new fitting with a slow leak… crummy hardware, or improper assembly, or random mismatch of fitting parts…

3) Would the simple leak test find a small leak that would be a challenge to the airspeed indicator or the altimeter?

4) Looks like if everything goes to plan… the simple leak test works…

5) I’ve entered the too many what-ifs zone here…

6) If I flew in IFC…. I would want a pretty strong leak test… to show my new parts on the system haven’t caused a surprise in the system. :)
 

7) It’s possible the ordinary leak tests actually do all this… and I’m blissfully unaware.

Best regards,

-a-

Yes a static leak test would tell you if the system leaks.  An A&P can conduct such a test per 91.411

Altimeter system and altitude reporting equipment tests and inspections.

(b) The tests required by paragraph (a) of this section must be conducted by -

(3) A certificated mechanic with an airframe rating (static pressure system tests and inspections only).

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Posted

Maybe there's just a misunderstanding of language here.  FlyingDude originally asked, "is my 24 monthly test void?", and Shadrach references "IFR certification".  But those terms are not mentioned in the actual regulation.  There is not a single "24 monthly test", or "IFR certification" that can become invalid.  There are instead three separate testing requirements in the regulation, involving three separate systems.  Per 91.411, each static pressure system, each altimeter instrument, and each automatic pressure altitude reporting system must be tested and inspected.  Per 91.411(2), opening the static system requires a re-test of the static system.  I think we all agree that event doesn't trigger a required re-test of the altimeter(s) or transponder(s), but I hope we all agree it triggers a re-test of the static system, because the regulation is plain as day on that point.

Per part 43 Appendix E, that static system test must be in a manner "acceptable to the administrator".  My interpretation is that a simple A&P/owner-assist leak check done with something like a handheld vacuum pump, stopwatch, and VSI doesn't meet that standard.  I think the standard requires specific training and equipment that the average A&P doesn't have, e.g. equipment like this.  I understand others may disagree.

I agree with Shadrach that the altimeter in a G5 is not a primary, certified altimeter, and does not require altimeter testing per 91.411; but that's orthogonal to the OP's question.

Posted (edited)
2 hours ago, PT20J said:

My understanding for 91.411 is that the full 24-month IFR certification must be performed by a repair station. Simply opening the static system requires a leak test that can be performed by an A&P. 

Skip

This is what I experienced recently when a VSI was replaced.  A leak test performed by an avionics shop; not a recert.  Can only speak to experience; not regs. 

Edited by DCarlton
clarified that the leak test was performed by an avionics shop
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Posted (edited)
10 hours ago, Vance Harral said:

Maybe there's just a misunderstanding of language here.  FlyingDude originally asked, "is my 24 monthly test void?", and Shadrach references "IFR certification".  But those terms are not mentioned in the actual regulation.  There is not a single "24 monthly test", or "IFR certification" that can become invalid.  There are instead three separate testing requirements in the regulation, involving three separate systems.  Per 91.411, each static pressure system, each altimeter instrument, and each automatic pressure altitude reporting system must be tested and inspected.  Per 91.411(2), opening the static system requires a re-test of the static system.  I think we all agree that event doesn't trigger a required re-test of the altimeter(s) or transponder(s), but I hope we all agree it triggers a re-test of the static system, because the regulation is plain as day on that point.

Per part 43 Appendix E, that static system test must be in a manner "acceptable to the administrator".  My interpretation is that a simple A&P/owner-assist leak check done with something like a handheld vacuum pump, stopwatch, and VSI doesn't meet that standard.  I think the standard requires specific training and equipment that the average A&P doesn't have, e.g. equipment like this.  I understand others may disagree.

I agree with Shadrach that the altimeter in a G5 is not a primary, certified altimeter, and does not require altimeter testing per 91.411; but that's orthogonal to the OP's question.

91.411 as I referenced above states that A&Ps can perform Static Pressure system checks and inspections (and no more)

The AC 43-6D advises what kind of test is advised in table 3.  Per the AC a field elevation verification and a static leak test.

Agree there is some confusion on the wording wrt IFR cert vs Pitot/Static test but I thought it was clear that his bird was IFR current and he was worried that having the G5 plumbed in would require a recert.  It seemed you read it the same way when you asked if he planned on flying IFR.  None of the three tests you mention are voided by plumbing the G5 into the P/S system.

All that is required is that the G5 be installed IAWPATTA and static leak test be performed. In addition to being legal, this is a perfectly reasonable and safe practice.

Edited by Shadrach
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Posted

Peanut gallery warning!

I'd also point out a leaky static system in a non-pressurized plane is not going to kill you in IMC.  It's hard to imagine that specialized equipment beyond what an A&P had or could do would be required.

A BLOCKED static system could kill you in IMC, though, and I imagine that also does not require any specialized equipment...  

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Posted
10 hours ago, carusoam said:

If you fly in IMC… how comfortable are you with a simple leak test?

I think MY answers depends on the noise introduced by the modification into the system: G5s have piezoelectric sensors. They don't really move, so if there's no leak in the system, they should be ninja-stealthy to other components. So I think I'll be ok. 

If I were replacing any of the mechanical instruments (like altimeter), then I'd be wary because they have mechanical moving parts, which might maybe alter the pressure in the system as they move (like what if it starts leaking at lower pressures because the bellows hit a punctured spot only after they've moved this many mm which happens only at 10000' and above? In that case, I'd get a re-cert even if it's not mandatory. 

That's just me.

Posted
8 hours ago, Shadrach said:

I thought it was clear that his bird was IFR current and he was worried that having the G5 plumbed in would require a resert

Confirm ;)

Posted
10 hours ago, Shadrach said:

What exactly do you think happens to the other components when a new component is added?  Perhaps they get jealous and and refuse play on the team?

That's my point in saying that G5 has a piezoelectric sensor that's just as stationary as the plastic tubes. So I agree that leak test would cover the only disruption that this plumbing may introduce.

In the case of my co-mooniac above who had a VSI installed, I'd be cautious and ask if that VSI had been tested in a system where it was connected to a primary altimeter which passed the IFR cert. That would show that it doesn't introduce any errors as its parts move above field elevation.

Thank you all for your help. This was a great discussion.

 

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Posted
7 hours ago, FlyingDude said:

I think MY answers depends on the noise introduced by the modification into the system: G5s have piezoelectric sensors. They don't really move, so if there's no leak in the system, they should be ninja-stealthy to other components. So I think I'll be ok. 

If I were replacing any of the mechanical instruments (like altimeter), then I'd be wary because they have mechanical moving parts, which might maybe alter the pressure in the system as they move (like what if it starts leaking at lower pressures because the bellows hit a punctured spot only after they've moved this many mm which happens only at 10000' and above? In that case, I'd get a re-cert even if it's not mandatory. 

That's just me.

Replacing a primary altimeter would entail a correspondence test in addition to the other tests. The reality is that a static system in an unpressurized airplane is about the least stressed plumbing on the whole aircraft. Maintaining and testing the instruments within the system is far more important to safety. 

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Posted
2 hours ago, Shadrach said:

Replacing a primary altimeter would entail a correspondence test in addition to the other tests. The reality is that a static system in an unpressurized airplane is about the least stressed plumbing on the whole aircraft. Maintaining and testing the instruments within the system is far more important to safety. 

This is true.  As an experiment, I recently took two altimeters for a ride recently in our C.   They sat in a box on the cabin floor so I could watch them.   Climbed to 7000' and at no point did they differ by more than a needle width from the panel mounted altimeter that passed IFR cert. in May.   One was a relic bought to adorn my desk, and the second was a really nice one that I was thinking about swapping out next time I visit my A&P.  My current altimeter says "Beechcraft" on its face and has a tiny 10'000 ft hand that hides behind the 1000' pointer when at 11,000.   This suggests that a leak in the static system behind the panel would have a negligible effect on the altimeter reading, in my aircraft at least.

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Posted
20 hours ago, Vance Harral said:

Per part 43 Appendix E, that static system test must be in a manner "acceptable to the administrator".  My interpretation is that a simple A&P/owner-assist leak check done with something like a handheld vacuum pump, stopwatch, and VSI doesn't meet that standard.  I think the standard requires specific training and equipment that the average A&P doesn't have, e.g. equipment like this.  I understand others may disagree.

AC 43.13 doesn't even describe the "how to" part of doing the leak check, I think because it is pretty trivial.  This is it:

12-57. SYSTEM LEAK TEST.
a. Pitot-static leak tests should be made with all instruments connected to assure that no leaks occur at instrument connections. Such tests should be accomplished whenever a connection has been loosened or an instrument replaced.
b. After the conclusion of the leak test, return the system to its normal flying configuration. Remove tape from static ports and pitot drain holes and replace the drain plug.

That's the entirety of the direction for a leak test and following it is "acceptable to the administrator" in the absence of any guidance from the factory.   In other words, if the Mooney S&M includes directions, then that's what's "acceptable to the administrator", otherwise, use the above from AC 43.13.  So take the tape off when you're done.

People often want to assume this stuff is harder or more complicated than it needs to be, which helps keep maintainers in business, but certainly isn't required.

The "System Test" stuff goes beyond the simple pitot/static leak tests and do require Repair Station status and the funky test box (which isn't really very sophisticated, either, it just has to be calibrated).

 

6 minutes ago, 0TreeLemur said:

This is true.  As an experiment, I recently took two altimeters for a ride recently in our C.   They sat in a box on the cabin floor so I could watch them.   Climbed to 7000' and at no point did they differ by more than a needle width from the panel mounted altimeter that passed IFR cert. in May.   One was a relic bought to adorn my desk, and the second was a really nice one that I was thinking about swapping out next time I visit my A&P.  My current altimeter says "Beechcraft" on its face and has a tiny 10'000 ft hand that hides behind the 1000' pointer when at 11,000.   This suggests that a leak in the static system behind the panel would have a negligible effect on the altimeter reading, in my aircraft at least.

The checks for the altimeter really mostly check for blockage, because a bare altimeter works fine as you've seen, but should read a little high in the cabin compared to the in-panel altimeter.   If the static alternate air is opened, which would bypass a block in the external static ports or plumbing, cabin pressure will indicate a little higher than full static pressure while in flight.   A loose altimeter inside the cabin will behave the same, and should agree with the in-panel altimeter if the alternate static air source is used (if you have one).   For these reasons the altimeter leak check tests the static plumbing for both blockage as well as for leaks so that the proper external static reference is used instead of internal cabin pressure.

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Posted
1 hour ago, EricJ said:

If the static alternate air is opened, which would bypass a block in the external static ports or plumbing, cabin pressure will indicate a little higher than full static pressure while in flight.   A loose altimeter inside the cabin will behave the same, and should agree with the in-panel altimeter if the alternate static air source is used (if you have one).

They agreed on the ground with the same altimeter setting.  They agreed in flight with or without the alternate static source on.   Opening the alternate static source caused a little change, but less than the width of the 100' needle.  I was surprised.  The panel-mounted altimeter passed IFR cert. in May.

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Posted

So based on this thread. A repair station can sign off the 91.413 transponder test with their test Equiptment. Myself as an A&P can sign off the .411 static test? 
I’ve always thought that the 91.411 was required for IFR certification to be done by the repair station.
 

So basically, when Sandia Fixes their software glitch. I can reinstall the sandia, leak test and sign the .411. And be legal for IFR flight.
Thus eliminating the expense and signature from the avionics shop? 
 

Cool!

-Matt

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Posted
7 hours ago, MB65E said:

So based on this thread. A repair station can sign off the 91.413 transponder test with their test Equiptment

No, this is NOT what this thread or the comments are saying. The gist is: if you have a system with current 91.413 and open/close the P-S system or add a new instrument, then a leak test is all you need to return to service. The 91.413 remains valid through the end of the original 24 month period from the previous test.

Two separate concepts...

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