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Any Simple DIY test kit available to detect position of bleed air leak?


edwardlcy
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...a simple DIY design for a test set to pinpoint the location of a bleed air leak at nacelle or dry bay area...

NO

But it's ("test set") already built into the aircraft, bleed air pressure gauge (gage).

If you have a leak your bleed air leak check will be BAD pressure drops faster than allowed.

30psi to 15psi in no less than 8.5 sec's or 16sec's (or 20 sec's) depending on model and local requirements.

Close one engine bleed air valve recheack leak rate... if it is still BAD (too fast) leave the first valve closed and close the next engine and repeat until you get a "Good leak check" takes longer than 8.5 sec's or 16sec's (or 20 sec's) depending on model and local requirements.

If you get a good leak check "After" closing an engine your leak is in that nacelle.

If all engines are closed, divide your wing or close one (Lt or Rt) wing isolation valve and recheck; still bad?

Aircraft with divider valve your leak is on the left side start checking for the leak.

Aircraft with wing isolation valves... close remaining wing isolation valve...

BAD check your leak is in the center section

Good your leak is on the last wing to be isolated...

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Do you have nacelle overheat detectors in your drybay? (around the engine bleed air valve) We call this the horse collar area the engine to wing contured panel...

Do your bleed air check with only the engine in question.

If the leak check is good the leak is in the ducts from your diffuser to your engine bleed air check valve.

After that the only way to find the leak is to use your eyes...check clamps and the "ribbed" "accordian" areas of each duct the movement of the engine makes these areas crack.

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edwardlcy,

You could consider a "man on the stand run" if your regulations allow. I had the honor of troubleshooting the exact same problem you identified, Nacelle overheat in reverse. I found the leak at the tenth stage where the bleed air collector mounts to the compressor case at the 3 oclock position. Changed the gasket and never had the problem with that engine again!

Ron

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edwardlcy,

You could consider a "man on the stand run" if your regulations allow. I had the honor of troubleshooting the exact same problem you identified, Nacelle overheat in reverse. I found the leak at the tenth stage where the bleed air collector mounts to the compressor case at the 3 oclock position. Changed the gasket and never had the problem with that engine again!

Ron

yup we do "man on the stand run" too sometimes, but visual for bleed air leak is hard to spot, i'm looking for an easier solution by means of a DIY portable flexi-rod type of infrared or temperature sensor test kit that will light up or sound an alarm to pinpoint location where there is a bleed air leak.

if you have dye penetrant crack detection kit available, spray suspect area with developer and do a short run - also works great for oil and fuel leaks

dye penetrant can only be used on rigid pipelines to check for cracks right? can it be applied where connecting pipelines and worn gaskets are?

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dye penetrant can only be used on rigid pipelines to check for cracks right? can it be applied where connecting pipelines and worn gaskets are?

doesn't matter. if there is an air leak it will be blown off, same with fluid leaks, it will stain. i just use the developer powder spray in the suspect area

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  • 8 months later...

Good day guys, was wondering if there is a simple DIY design for a test set to pinpoint the location of a location of a bleed air leak at nacelle or dry bay area, please do share thanks!

Flir has come out with very reasonable Heat Guns. They have a Flir Rep "Dan" I worked with in the past. The guns can be bought with a GPC Card and show very accurate temp. changes. It gives you like a 6th sense of visual sight where you can see things like never before. The digital laser guns are worthless for troubleshooting. They can give you the temp. of a target the size of a sheet of plywood. The visual screen will allow you to find instantly where the problem is.

I think that every support section should have a Flir gun on hand. From a hot spot in wiring to brake checks these guns have potential. The industrial maintenance industry has used them for years.

Joe

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  • 3 weeks later...

I've always used an infared gun, but do the run at night so the plane is good and cold which allowes you to spot the leak quicker.

Another tool I like to use for fuselage pressure leaks (kind of off topic but kind of relates to air leaks) is simply baby powder puffed into the air from inside the plane.

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  • 3 weeks later...

I use a ruler with toilet paper taped to the end of it. Works good and it's cheap....budget crisis and all.

We used an inspection mirror or mechanical fingers with paper taped to the end. would also slice the paper so it had like brush bristles... Costs nothing. You always have paper, tape and the tool box...

Though maybe the thermo imaging camera would allow checking without doing the "Man On The Stand" turn...

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we use the tp for any pressurization leaks from inside the aircraft, and man on the stand is old school but seems to work well. I knew some guys from LM that used the thermal imaging device with little success. I can recall a long time ago trimming a Pratt N Whitney on a Boeing 707 standing beside and fighting the fan blow by, that was exciting stuff.

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