Do I need new IFR Certs after installing a new VSI?

poadeleted21

poadeleted21

Touchdown! Greaser!
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Aug 18, 2011
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My plane is in the shop right now getting a CDI overhauled, compass swing and an encoder adjustment. In a week or two I'll be putting in all new gyros and a new VSI. My IFR Certs run out next month, so I was just going to have him do the static test and transponder test monday. But my concern is, will I have to do it all over again if I install a new VSI in a couple of weeks?
 
bartmc said:
My plane is in the shop right now getting a CDI overhauled, compass swing and an encoder adjustment. In a week or two I'll be putting in all new gyros and a new VSI. My IFR Certs run out next month, so I was just going to have him do the static test and transponder test monday. But my concern is, will I have to do it all over again if I install a new VSI in a couple of weeks?
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no,,,
 
Tom is correct as far as he went (you don't have to do it all over), but did not give the full answer. Here's the relevant portion of the rule:
Sec. 91.411

Altimeter system and altitude reporting equipment tests and inspections.

(a) No person may operate an airplane, or helicopter, in controlled airspace under IFR unless--
(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;
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If you do the full 91.411 and 91.413 tests now, the altimeter and Automatic Pressure Altitude Reporting Equipment and ATC Transponder System Integration tests will not have to be repeated in two weeks when you install the new VSI. However, since the VSI is hooked up to the static pressure system, you're going to have to open and close the system to hook up the VSI. Therefore, the following part of the 91.411-required test will have to be repeated at that time:
(a) Static pressure system:
(1) Ensure freedom from entrapped moisture and restrictions.
(2) Determine that leakage is within the tolerances established in Sec. 23.1325 or Sec. 25.1325, whichever is applicable.
(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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Replacing an instrument isn't considered opening the system, removing and replacing lines, fittings, etc, is opening the system.
 
Tom-D said:
Replacing an instrument isn't considered opening the system, removing and replacing lines, fittings, etc, is opening the system.
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So tell me how you replace the VSI without removing the fittings that connected the static system to the old VSI. Or provide some written guidance on point. And if nothing else, you don't know for sure if the new VSI case leaks until you test it.
 
Maybe I'll just go get my plane before he adjusts the encoder, it's on the edge of legal and take it back for all the tests after the new VSI arrives and have him install it, do the encoder adjustment and all my tests at once. Bout to start hanging out in the clouds and want my system well oiled.

Encoder is brand spanking new, the dude that installed it, never bothered to calibrate it and never bothered to do the trasponder/static tests but he did bother to bill me for it.
 
Ron and R&W agree! It's GOT to be true!

<P.S. I've made note of the date and sent Satan a pair of ice skates>

And my tongue-in-cheek humor is not meant as a sign of disrespect towards either of the two.
 
bartmc said:
Maybe I'll just go get my plane before he adjusts the encoder, it's on the edge of legal and take it back for all the tests after the new VSI arrives and have him install it, do the encoder adjustment and all my tests at once. Bout to start hanging out in the clouds and want my system well oiled.

Encoder is brand spanking new, the dude that installed it, never bothered to calibrate it and never bothered to do the trasponder/static tests but he did bother to bill me for it.
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That sounds like an efficient idea.
 
Rotor&Wing said:
Replacing an instrument is considered opening the system.
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Well Well different views from different FSDOs again.

There are a whole lot of aircraft out there that need big red tags

AC 43-6B page 3 para 1,
(1) That required test equipment, technical data, and qualified personnel are available to perform a static system leak check and other testing as required by § 91.411(a)(2), to verify the integrity of the newly installed or altered system.

Tell me what was altered, or how much system you installed
 
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Ron Levy said:
So tell me how you replace the VSI without removing the fittings that connected the static system to the old VSI. Or provide some written guidance on point. And if nothing else, you don't know for sure if the new VSI case leaks until you test it.
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Call your local FSDO for guidance, I do.
AC 43-6B page 3 para 1,
(1) That required test equipment, technical data, and qualified personnel are available to perform a static system leak check and other testing as required by § 91.411(a)(2), to verify the integrity of the newly installed or altered system.

Tell me what was altered, or how much system you installed.
AS far as how do you know the case doesn't leak? don't buy junk get the certified instrument repair station maintenance release/ work order, or what have you. that it was tested on the bench.
 
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If a person was actually trying to use some of these threads as a way to learn about something the only thing they'd learn is nothing appears to be black & white.
 
EppyGA said:
If a person was actually trying to use some of these threads as a way to learn about something the only thing they'd learn is nothing appears to be black & white.
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You can look this stuff up at "faa.gov" they give us the AC and the Regulations and if you doubt you can't understand them you can ask for guidance at OKC. Or you can ask your A&P-IA we are actually required to know this sh-t.
 
Tom-D said:
You can look this stuff up at "faa.gov" they give us the AC and the Regulations and if you doubt you can't understand them you can ask for guidance at OKC. Or you can ask your A&P-IA we are actually required to know this sh-t.
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And different A&P-IA(s) will say different things even in the same district.
 
jesse said:
And different A&P-IA(s) will say different things even in the same district.
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True, some know how to look it up, some simply go with what they were told.
 
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Tom-D said:
True, some know how to look it up, some simply go with what they were told.
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I'm curious how you'd know that the re-attached fittings and new VSI didn't leak enough to fail the leakdown test unless you actually performed the test?
 
Again, it's up to the individual signing off the work to make the determination.

In the instance of the OP, if it's the same shop doing the IFR certs that will be installing the VSI I would assume they would advise their client to wait and do it all at once for the reason's cited in Mr. Levy's post #3.

If Tom was doing the work and he believes his interpretation is correct then he can sign off the work as he sees fit.

My reasoning for following Mr.Levy's post #3 as an A&P is I believe once the system is "opened" (any part) then the appropriate test equipment should be hooked up to insure the integrity of the system has not been compromised, such as a defective instrument, broken or loose fitting, or cracked line. It's not uncommon, especially in older aircraft to crack a line or fitting when R&Ring an instrument. An I have seen instruments off the shelf have a defect. Without doing the test it would be hard to tell if the system integrity has been maintained. (As asserted in Lance's post #13 above)

While a small leak in a pitot/static system will cause errors in the non pressurized aircraft, it will make a huge difference if the aircraft is pressurized. That's why pressurized aircraft have specific maintenance instructions pertaining to opening a pitot/static line inside the pressure vessel and do require the system be tested anytime the system is opened.

YMMV.
 
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gismo said:
I'm curious how you'd know that the re-attached fittings and new VSI didn't leak enough to fail the leakdown test unless you actually performed the test?
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It's a static system, the pressure inside is the same as the pressure on the outside. any leakage will be very minor.

AS R&W has pointed out, pressurized aircraft have different required tests.

Read the AC I pointed out, If the FAA thought a test was required they would have written it in there. The AC is an excepted method of compliance, but not the only way to do the action, the first post asks if the test is required, It is not.
 
Rotor&Wing said:
Again, it's up to the individual signing off the work to make the determination.

Buy using the guidance given in AC I pointed out written and approved by the FAA.

In the instance of the OP, if it's the same shop doing the IFR certs that will be installing the VSI I would assume they would advise their client to wait and do it all at once for the reason's cited in Mr. Levy's post #3.

Unless the test is required by the aircraft maintenance manual, the FAA does not require it either, and that was the question by the first post.

If Tom was doing the work and he believes his interpretation is correct then he can sign off the work as he sees fit.

My reasoning for following Mr.Levy's post #3 as an A&P is I believe once the system is "opened" (any part) then the appropriate test equipment should be hooked up to insure the integrity of the system has not been compromised, such as a defective instrument, broken or loose fitting, or cracked line. It's not uncommon, especially in older aircraft to crack a line or fitting when R&Ring an instrument. An I have seen instruments off the shelf have a defect. Without doing the test it would be hard to tell if the system integrity has been maintained. (As asserted in Lance's post #13 above)

While a small leak in a pitot/static system will cause errors in the non pressurized aircraft, it will make a huge difference if the aircraft is pressurized. That's why pressurized aircraft have specific maintenance instructions pertaining to opening a pitot/static line inside the pressure vessel and do require the system be tested anytime the system is opened.

YMMV.
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Read the AC your boss approved it and you should follow it. that test is not required or it would state the requirement in the AC.
Just remember, what's safe, isn't always legal, what's legal, isn't always safe.
 
Rotor&Wing said:
An I have seen instruments off the shelf have a defect.
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I hope as a agent of the FAA you jambed them with their 8130-3 and brought their Quality control up to standards, isn't that your job? Otherwise why do we have the FAA, CRSs, and the form.?????
 
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Tom-D said:
I hope as a agent of the FAA you jambed them with their 8031-3 and brought their Quality control up to standards, isn't that your job? Otherwise why do we have the FAA, CRSs, and the form.?????
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So an instrument is damaged in shipping, or damaged after it leaves the shop that signed off the repair and you want to hang them for something outside of their control? :dunno:

Remember, it's up to the installer to determine airworthiness. You do remember that don't you?
 
Rotor&Wing said:
So an instrument is damaged in shipping, or damaged after it leaves the shop that signed off the repair and you want to hang them for something outside of their control? :dunno:

Remember, it's up to the installer to determine airworthiness. You do remember that don't you?
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Yep, and when I receive a damaged product I don't install it.
 
Rotor&Wing said:
Then without doing a proper test with the proper equipment how would you know? Not all damage is visible to the eye, hence the requirement for test equipment and procedures.
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It's called a functional check called out in the AC.
 
Rotor&Wing said:
As far as I know, my "boss" hasn't approved any AC's that I'm aware of. He's the manager of my office and deals with our local issues. :dunno:
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Ultimately all Federal employees have a boss. I know because I were one too. :)
 
Rotor&Wing said:
I agree.

Have any extra?
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I do, but Northrop Grumman policies forbid me from sharing it with you, lest it be construed as an inappropriate attempt to influence the Gov't.:D

And, no, I'm really NOT making this up. I've had to "register" all the feds with which I have a pre-existing personal relationship, so that if we exchange gifts or go fly together or otherwise interact it doesn't run the risk of having us debarred.

If you think the Federal Aviation Regulations (FAR) is bad, try the Federal Aquisition Regulations (FAR)...
 
Tom-D said:
Well Well different views from different FSDOs again.
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I know that sometimes FSDO Inspectors give guidance that isn't consistent with HQ policy or guidance from other FSDO's, but I'd like to see in writing the guidance from any Airworthiness Inspector in any FSDO in the country that says disconnecting the static line from an old VSI and connecting the static line to a new VSI doesn't constitute "opening and closing of the static pressure system."
 
Ron Levy said:
I know that sometimes FSDO Inspectors give guidance that isn't consistent with HQ policy or guidance from other FSDO's, but I'd like to see in writing the guidance from any Airworthiness Inspector in any FSDO in the country that says disconnecting the static line from an old VSI and connecting the static line to a new VSI doesn't constitute "opening and closing of the static pressure system."
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Me too. I would also like to see that in writing from an official. I am in school to be an A&P, and am not very far in, but to me, it would most definitely seem that putting in a new VSI requires an opening of the system. Installing a new one without, would be a neat trick.
 
Ron Levy said:
I know that sometimes FSDO Inspectors give guidance that isn't consistent with HQ policy or guidance from other FSDO's, but I'd like to see in writing the guidance from any Airworthiness Inspector in any FSDO in the country that says disconnecting the static line from an old VSI and connecting the static line to a new VSI doesn't constitute "opening and closing of the static pressure system."
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As you know you are again looking for some rule that does not exist, read the AC and tell where the FAA says it is required. If it is required they certainly would say it is in the AC, and they do not.

The AC is an except able means of compliance, and the AC says a functional check is all that is required. Other wise every time you opened and closed the alternate source valve you would be required to do the static test required by FAR 91.
 
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denverpilot said:
Do we really need yet another Advisory Circular for common sense? :(
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No we already have one that covers this topic.. AC 43-6B. it is all about the transponder system and the static system driving the digitizer for the mode C/A and other instruments, it is very detailed and considered the method of compliance for testing the system.
 
Now now, kids.

He's got a point with the Alternate Static thing...

And there's always those Cessnas that had the Alternate Static port that had a sticker on it with the part number or some-such, that over time, slid over and blocked BOTH ports and became an AD... since the very device that was supposed to give you an Alternate had now blocked BOTH systems...

Usually the sticker would move when you went to pull the Alternate Static, at an inopportune time.

Murphy lives. Stuff happens.

Static being just the world outside for the most part in the non-pressurized stuff we all fly... the errors aren't going to be too massive if there's a leak into the cockpit area. No more than if the Alternate Static port is open, anyway... yeah, cockpit is slightly lower pressure... but not a huge difference.

Tom's point is decent in showing that it won't make a heck of a lot of difference, and that probably explains the ambiguity in the regs, too. Not important enough to the FAA for them to get too uptight about it.

We could do a test and yank the hose off the blind encoder somewhere nice and well hidden behind their panel, of someone's airplane who's freaking out in this thread here, and see if they notice the difference on their next flight. :rofl: :popcorn:
 
denverpilot said:
Tom's point is decent in showing that it won't make a heck of a lot of difference, and that probably explains the ambiguity in the regs, too.
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Tom is wrong, and there is no ambiguity in the reg. It requires the check whenever the system is opened or closed, and that happens when you disconnect the hose from one instrument and connect it to another. The fact that there's an AC that says the check must be performed when certain conditions exist does not mean it is not required in other circumstances.

Not important enough to the FAA for them to get too uptight about it.
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Really? And which FAA Inspector told you that in writing? Tell you what -- you call any FSDO and ask the question, and see if you get any answer other than what R&W and I said.
 
Ron Levy said:
Tom is wrong, and there is no ambiguity in the reg. It requires the check whenever the system is opened or closed, and that happens when you disconnect the hose from one instrument and connect it to another. The fact that there's an AC that says the check must be performed when certain conditions exist does not mean it is not required in other circumstances.
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What other circumstances ?

The AC is well written and proves to all the maintenance types that I am right.

When you read the maintenance regs as well as you do the IFR regs they will give you your IA ship.

The term "Opening the System" is not defined in any regulations simply because the FAA isn't going to write a broad statement that will contradict the manufactures manuals written by a dozen different manufacturers.

You continually call me wrong yet the AC says different on page 3 para 1 it says the test is required when the SYSTEM is newly installed or altered.
Now tell the readers which it is, when you install a new gauge does that alter the SYSTEM? or did you remove and install the whole system in doing so.
 
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