Tip: Static leak test

Reading up on this site I read where a fells used a syringe to create the vacuum for the static system leak check. The idea is you can check you system, find and correct leaks before you get the official check. I did not want to crawl into the tail to tap into the line there. What I came up with was this;



I drilled a hole in the center of the suction cup to take the 1/4" hose, I put it over the static port with the opposite one taped over. You have to hold the cup while pulling the plunger, once there is a good amount of suction the cup will stay in place. I taped the hose to the side then slowly set the altitude. I used a snake camera with a removable monitor to give me a view of the altitude window back by the static port.

Set the altitude to 1000 feet or nearly so and then left it for 5 minutes, no change in altitude. Now I have a new tool for my tool box.

Start of test: You can see the snake camera pointed toward the EFIS



After 5 minutes:



BTW The SafeAir kit is awesome, the connectors are kind of large but easy to use.

Not sure what your field elevation is but the static system test per 23.1325 requires the leak rate be tested at 1000 ft above field elevation, limit is 100 ft/min.

100 per minute or 100 per hour? I had the 100 per minute leak and pounded my head many times to fix it to pass a 100/ hr perceived requirement.
Either way, I now have zero leaks. It did cost me a heated pitot tube ($400 off ebay). I go for the offical IFR cert Monday in Columbus, Ga.

The Gretz I had, leaked where the copper tube was bonded to the body. Gretz is going to replace it, but I needed one now and did not want to wait for shipping to Austrailia. When I get the new one back, I will offer it up on VAF. BTW, the pitot tube off of ebay is certified and chrome. Chrome all by itself makes anything look faster while standing still.

From 23.1325:

(i) Unpressurized airplanes. Evacuate the static pressure system to a pressure differential of approximately 1 inch of mercury or to a reading on the altimeter, 1,000 feet above the aircraft elevation at the time of the test. Without additional pumping for a period of 1 minute, the loss of indicated altitude must not exceed 100 feet on the altimeter.

Garage elevation

I did not realize the official test was 1000' AFE but I was just interested in confirming I did not have a leak in the static lines since I just installed them. I don't think I can self certify the pitot static check so I will have to get an avionics shop to do the official one.

My garage elevation is 208' so I guess I needed to go to a higher altitude, easy to do with the little set up I made.

If anyone knows, can you do your own IFR pitot static check?

RVG8tor said:

I did not realize the official test was 1000' AFE but I was just interested in confirming I did not have a leak in the static lines since I just installed them. I don't think I can self certify the pitot static check so I will have to get an avionics shop to do the official one.

My garage elevation is 208' so I guess I needed to go to a higher altitude, easy to do with the little set up I made.

If anyone knows, can you do your own IFR pitot static check?

Click to expand...

This question comes up from time to time:
"Can the builder with a repairman certificate for the aircraft he built perform his own static system/altimeter check or transponder certification?"

Answer:
No. Although the CFR's do authorize the "manufacturer" of the aircraft to conduct the tests, the builder of an amateur-built aircraft does not meet the FAA's definition of a "manufacturer".

Confused

Walt, quick question if all instruments Were vented to the cabin why do a leak check ? Also I used a druck air data test set I had access to and conducted the test myself. Why do I not qualify as a manufacturer ? Not trying to be a pain but I would like to fly the aircraft to the avionics shop after the first series of flights. Is this not allowed per FARs ?
Thanks
I am new to this
Phelps

I figured I would just tack onto another useful thread:

It is that time again for us to do (have done) the static and transponder check. I figured I would setup to test the static for leaks before standing there at the avionics shop with a leaky system. This is mostly for those that might follow.

First, don't paint the edge of a stripe within 1.5" of the static ports. Geez, how silly of me to allow that to happen. It just makes the suction cup impossible to seal against the side of the airplane. I had to wet sand the edge of that paint way down in order to get things to seal up reliably. Second, all of the source of any/all of my static leaks have been at NPT threads of fittings. As far as I'm concerned, lots of teflon tape is required here. Sometimes more than you would think. Third, electrical tape over the other static port doesn't work for me in the 100deg hangar. The sure thing is aluminum tape.

Ok, so the suction cups are from Home Depot "5lb picture hangar". Drill a hole, press fit some tubing. I used some 1/8" barb fittings that I clipped off as an expansion insert into the tubing. I rigged up a tiedown strap with a hole in it to maintain a secure press of the suction cup on the side of the airplane. I also used fuel lube as a positive sealing agent to overcome the remainder of the paint line. It doesn't take much movement of the syringe to do the trick. Much care is in order.

I have this really fun digital differential pressure instrument (manometer and more) that has a high precision that is perfect for this stuff. I used it for some plenum testing years ago and just had to drag it out for this project for the fun of it. It is nice having a second direct source leak down test instrument for diving into individual components. The syringe obviously has its own leak as the plunger is pulled back down, so crimping the tubing is critical for real results.

I'll say it again. Teflon Tape! Good times. Build on.

Scott, good info and photo spread.

One tip for your tip------when you do a hole in something like this strap, burn through it with a heated metal rod, the edges of the hole will not fray.

Mike S said:

Scott, good info and photo spread.

One tip for your tip------when you do a hole in something like this strap, burn through it with a heated metal rod, the edges of the hole will not fray.

Click to expand...

Well, of course, but I gnawed that hole with my teeth as there seemed not to be another sharp or hot tool in sight at the time. I think I did pretty good, don't you . I did think about heating up a phillips head screwdriver with the airplane battery... Ok, so I wasn't on a desert island after all.

Two things........ I placed a barbed "T" with a vacuum cap under the panel (well,behind and on top... tilt-up) for static tests. Now all I do is tape off the ports with electric tape and pull a suction from the test T as I sit inside.

I gave up on teflon tape to seal the 1/8" pipe threads on any gauge connection. I use GB (Gardner Bander) 1/2" X 7 mil electrical tape. It DOES NOT shred. But it is thin enough to couture to the threads and seal hand tight.

gasman said:

Two things........ I placed a barbed "T" with a vacuum cap under the panel (well,behind and on top... tilt-up) for static tests. Now all I do is tape off the ports with electric tape and pull a suction from the test T as I sit inside.

Click to expand...

That seems to be a common theme that has potential failure built in. My interest is in testing a closed system for certification in exactly the same configuration as the avionics shop that I'm going to take it to for their signature.

Do some shops really accept at "test port" that is opened for the test, then closed after validation?

s24789 said:

Walt, quick question if all instruments Were vented to the cabin why do a leak check ? Also I used a druck air data test set I had access to and conducted the test myself. Why do I not qualify as a manufacturer ? Not trying to be a pain but I would like to fly the aircraft to the avionics shop after the first series of flights. Is this not allowed per FARs ?
Thanks
I am new to this
Phelps

Click to expand...

Missed this question a long time ago, but the answer can also be found in CFR 23.1325: (I've never encountered an aircraft that could be certified for IFR without a static system)

(a) Each instrument provided with static pressure case connections must be so vented that the influence of airplane speed, the opening and closing of windows, airflow variations, moisture, or other foreign matter will least affect the accuracy of the instruments except as noted in paragraph (b)(3) of this section.

(b)(3) If a static pressure system is provided for any instrument, device, or system required by the operating rules of this chapter, each static pressure port must be designed or located in such a manner that the correlation between air pressure in the static pressure system and true ambient atmospheric static pressure is not altered when the airplane encounters icing conditions. An antiicing means or an alternate source of static pressure may be used in showing compliance with this requirement. If the reading of the altimeter, when on the alternate static pressure system differs from the reading of the altimeter when on the primary static system by more than 50 feet, a correction card must be provided for the alternate static system.

scard said:

I figured I would just tack onto another useful thread:

It is that time again for us to do (have done) the static and transponder check. I figured I would setup to test the static for leaks before standing there at the avionics shop with a leaky system. This is mostly for those that might follow.

Click to expand...

A simpler (and legal) way to do this is to block both static ports and connect to a connection or point in the static system that is easy to access and may be readily inpected when reconnected.

scard said:

That seems to be a common theme that has potential failure built in. My interest is in testing a closed system for certification in exactly the same configuration as the avionics shop that I'm going to take it to for their signature.

Do some shops really accept at "test port" that is opened for the test, then closed after validation?

Click to expand...

Yes, and it is an acceptable means.

Walt said:

Yes, and it is an acceptable means.

Click to expand...

Excellent! Way easier than the alternative. I will take 10min. and make it easy for the next check.

Scott, and the next time you go to install fittings (pipe) in gauges, try the 7 mil electric tape i mentioned. It seals very well hand tight. ACE hardware has it.

And don't forget to test the pitot system for leaks also.

Walt,

Do you have a reference handy for "manufacturer"?

This is purely academic. The cost of keeping the required equipment certified makes doing it yourself not cost effective.

Unless you hold some type of manufacturing approval from the FAA (PC, PMA, STC etc) then you are not considered a "manufacturer".

CFR 21.6

21.6 Manufacture of new aircraft, aircraft engines, and propellers.
(a) Except as specified in paragraphs (b) and (c) of this section, no person may manufacture a new aircraft, aircraft engine, or propeller based on a type certificate unless the person?

(1) Is the holder of the type certificate or has a licensing agreement from the holder of the type certificate to manufacture the product;

Walt said:

CFR 21.6

21.6 Manufacture of new aircraft, aircraft engines, and propellers.
(a) Except as specified in paragraphs (b) and (c) of this section, no person may manufacture a new aircraft, aircraft engine, or propeller based on a type certificate unless the person?

(1) Is the holder of the type certificate or has a licensing agreement from the holder of the type certificate to manufacture the product;

Click to expand...

Walt...

I think the cite is really intended to say that no one "may manufacture based on a type certificate" rather than say "no one may manufacture." As I read it, I have an entirely different interpretation.

My sense is that the builder of an experimental aircraft can check the static system. The builder cannot do the tests required by 91.411 & 91.413 (altimeter / transponder). But solely static - I believe they can.

So, you have a RV that flies VFR only in airspace not requiring a transponder. There is no transponder aboard. 91.411 and 91.413 do not apply.

I think once you enter airspace requiring a transponder, say a Mode C, then the two regs kick in and an authorized shop has to do the required testing.

But ... I'm old now - seldom correct about anything.

Dan

EAA has a write-up on this:

http://members.eaa.org/home/homebuilders/faq/4Transponder and Pitot Static Tests.html


The FAR?s authorize the "manufacturer" of the aircraft to conduct the tests However, the builder of an amateur-built aircraft does not meet the FAA?s definition of a manufacturer. The FAA, in Order 8130.2, defines a manufacturer as a Production Approval Holder (PAH). Some examples of a PAH would be the holder of a Production Certificate (PC), a Parts Manufacturing Authority (PMA), and Technical Standards Order Authorization (TSOA). An amateur builder does not fit this definition. Thus, the amateur-builder cannot perform the transponder and pitot/static tests on his/her homebuilt.

Static test - Alternate Static Source

I placed a -4 AN 832 bulkhead union through the IP, tee'd it into the static system, and placed an AN929 screw cap on the end of the bulkhead fitting. The cap is lubed with fuel lube and tightened finger tight. Loosening the cap in flight provides alternate static source in the event that both static ports are plugged, and it also provides an easy connection for static system leak tests. - Roger

A flared fitting will not seal reliably unless it tightened with a wrench.

Do not use "fuel lube" on ANY flare fitting (especially true for fuel).

Fuel Lube question ??

Hi, Walt!

Thanks for the prompt reply. Not sure I understand your rationale...
In this application the Fuel Lube (actually EZ Turn) is used to create a seal at low torque values. Remember we are talking about air at less than one atmosphere here. The EZ Turn also prevents the cap from vibrating loose when it is open, and makes for more consistent torque when finger tightening it.

From personal experience, EZ Turn on flare nuts appears to prevent galling of the anodized aluminum nut and fitting. I do not use it to lubricate the flare.

I really would be glad to understand the rationale behind your cautions and learn from your vast experience.

Copied from Spruce's description of EZ Turn...
"EZ Turn is a specialty lubricant/sealant used for fuel and oil line valves & is resistant to high temps. Especially effective where high octane fuels and aromatics are present. EZ Turn is also extremely efficient as a gasket paste & anti- seize agent. EZ Turn will not gum, crack or dry out. Each shipment is independently tested. Excellent for tapered plug valves, aircraft engine manufacturing, and marine applications. EZ Turn is the functional equivalent of fuel lube. 1 Lb. can "

Well, personally, I've not found a good use for fuel lube except to make a sticky mess on anything you use it on. It also won't clean up with any solvent I use and will not desolve in fuel or oil, hence my caution on using it around fuel systems. I'm really just not sure what it's ideally suited for.

My philosphy is simple, use "hardware" for it's intended purpose, don't try to invent a new way of doing things (refer to the bible 43-13).

Flared fittings don't need sealant or antisieze, they just need to be properly torqued to seal (and so they won't fall off).

If you want an alternate air source, use an alternate air switch available from many sources.

Thanks, Walt,
Yes, it's messy. IIRC, isopropyl alcohol cuts it. Other uses >> ??... use as a temporary adhesive to hold small gaskets in place against gravity until the mating part can be installed and secured?? ...?? helps determine who has been fiddling with your toolbox after hours?? (fingerprints everywhere) ?? sticks four AN washers together when adjusting control horn bolt spacing. Baby oil works better on the waterbed, but is almost as hard to clean off. So I hear.

I use it to hold washers to my fingertip when installing them in particularly difficult places.

Oh, and we used some sunday when someone's cessna ended up in a ditch, on a piece of tape to tape up his fuel vent which was leaking

Denatured Alcohol kills Fuel Lube

RKellogg said:

Thanks, Walt,
Yes, it's messy. IIRC, isopropyl alcohol cuts it. Other uses >> ??... use as a temporary adhesive to hold small gaskets in place against gravity until the mating part can be installed and secured?? ...?? helps determine who has been fiddling with your toolbox after hours?? (fingerprints everywhere) ?? sticks four AN washers together when adjusting control horn bolt spacing. Baby oil works better on the waterbed, but is almost as hard to clean off. So I hear.

Click to expand...

Excellent! You just sent me running to the shop. I don't know about isopropyl, but I have quarts of denatured alcohol in the shop (also good for cleaning and not killing our canopies), and I do use fuel lube for stuff that would probably appall Walt, like temporarily sealing a static suction cup. Denatured alcohol does cut it. New to me. A gob stuck or smeared on a big piece of RV8 fuselage aluminum, all the way down to, "Oh, no, I just accidentally stuck my finger in this 1lb can of fuel lube that my grand children will still be trying to use up." No more sticky fingers.

Fuel lube + Alcohol = good buddies! Alcohol + fuel lube = ?? too much alcohol ?? The kind banter provides value.

Oops, I didn't get it all off, now my keyboard is sticky, I wonder what alcohol does to abs plastic, wait, I know that answer already .

scard said:

Fuel lube + Alcohol = good buddies! Alcohol + fuel lube = ?? too much alcohol ?? The kind banter provides value.

Oops, I didn't get it all off, now my keyboard is sticky, I wonder what alcohol does to abs plastic, wait, I know that answer already .

Click to expand...

Good info, my usual cut everything solvent MEK won't touch the stuff so I usually just end up repeatedly wiping it on my pants then when I get home: "Honey can you wash these for me, I got something on them that just won't come off"

Fuel lube

Makes a dandy plug in your injectors if you leave a small booger of it anywhere in the fuel system.
Seals real well and won't dissolve!
Anything that needs fuel lube on it in the fuel system should have a very thin film only.
Tim

Paid 2013!

Fuel Lube plugs small orfices in fuel system... yikes!

Tim's point about Fuel Lube not dissolving in fuel, and plugging fuel system orifices is ironclad rationale for Walt's Rule about never using Fuel Lube (or EZTurn) on the flare of tubes / hoses for fuel or oil systems. Every fuel system has small orifices, plugging one with a small booger of Fuel Lube could certainly ruin your entire day... Thanks, Tim! Thanks, Walt, for sharing your knowledge base!
?? It's puzzling/scary that both of these products were developed for sealing and lubricating tapered plug valves in fuel systems... perhaps with care to minimize amount used it doesn't create problems.??
- Roger

Well I thought I would throw in my 2 cents just to help out a bit.

here is the full 14 cfr 91.411 regulation if anybody is interested...it is pretty clearly stated what can and cannot be done regarding static systems/transponders

?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?

(1) Within the preceding 24 calendar months, each static pressure system, each altimeter instrument, and each automatic pressure altitude reporting system has been tested and inspected and found to comply with appendices E and F of part 43 of this chapter;

(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; and

(3) Following installation or maintenance on the automatic pressure altitude reporting system of the ATC transponder where data correspondence error could be introduced, the integrated system has been tested, inspected, and found to comply with paragraph (c), appendix E, of part 43 of this chapter.

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

(1) The manufacturer of the airplane, or helicopter, on which the tests and inspections are to be performed;

(2) A certificated repair station properly equipped to perform those functions and holding?

(i) An instrument rating, Class I;

(ii) A limited instrument rating appropriate to the make and model of appliance to be tested;

(iii) A limited rating appropriate to the test to be performed;

(iv) An airframe rating appropriate to the airplane, or helicopter, to be tested; or

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

(c) Altimeter and altitude reporting equipment approved under Technical Standard Orders are considered to be tested and inspected as of the date of their manufacture.

(d) No person may operate an airplane, or helicopter, in controlled airspace under IFR at an altitude above the maximum altitude at which all altimeters and the automatic altitude reporting system of that airplane, or helicopter, have been tested.

As I have said before I am not that familiar with regulations of homebuilts...however it very clearly states in this regulation and the ac43.13 that you cannot arbitrarily install a test fitting in a static system and use it as an acceptable point of test. However if that point were considered a drain it would be ok.

Now all of that being said I doubt many shops are gonna care about that much...it is sort of a gray area

Now if for some reason you did not want to install a test point in your static system. One way to slightly improve upon your idea RVG8tor if you are having problems getting a good seal. We use a very similar method to attach our test set to static ports on aircraft that either the adapter is not available or when the adapter is it just plain sucks lol. If you go to a tac and feed store or a tractor supply they will have injection needles in different sizes. A 20 guage fits in almost all static ports. Grind the tip to flat using a sander (do not cut it off with cutters of any sort). Buy plummers putty or something similar. Shove the needle into the same clear tube that you are already using. Put aluminum tape over the port and poke a small hole in the tape. put plummers putty around the hose and needle. Place the needle through the hole in the aluminum tape and form the puddy to the hose and the aircraft in a cone shape. Like a volcano erupting your test hose out of the static port. Work all of the putty with your fingers until the hose and needle are firmly in place and if you did it right you have a leak free static adapter that is reusable. Next time just reform the putty to the aircraft (or whatever you are leak testing) just be sure not to get any putty in the needle tip and clog it up.

What about...?

I didn't see any mention regarding the original post of the need to draw the same vacuum on the pitot system when doing a static check - at least if you have an analog a/s indicator. I found this out the hard way. I did my original testing with the EAA manometer, drawing on the static port only. Since the analog a/s indicator is just a differential pressure gauge reading between static and pitot pressures, I drove the needle negative and ruined the instrument. By drawing the same vacuum (with a tee to the pitot) on both pitot and static, you protect your ASI (it shouldn't move) and still get the same static check. You also get a check of the integrity of your pitot system. I don't know if the same thing is true for the glass panel pressure transducers, but since I do it this way every time, it doesn't matter.

You make a good point that I am sure has caught out many.

OK to do a AGL +1000' or so, static only leak test.
However it wont drive "the needle negative" on the ASI. It should cause the ASI to read (from memory) about 148 knots. (At about sea level pressures)

As you say, the Pitot and Static must be balanced/tee'd together for higher tests. IE, Transponder/Mode C outputs. Otherwise kiss goodbye your (steam) ASI.

Pitot/Static test sets have a "cross bleed" control/tap to equalize the two pressures, as the system is evacuated.

Paul.

Pitot pressure increases relative to static to read an increase in airspeed. So if you draw a vacuum on the static and leave the pitot at atmospheric, you should read an increase in airspeed. If you read a negative airspeed and damaged a gauge, you must have pulled a vacuum on the pitot line, not the static line.

Yup

You are right. It pegged the asi, which is what ruined it. It's been a while so I misremembered.