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Transponder testing


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Go to your local LAME, (gympie aircraft maintenance)? Usually an avionics LAME will come to such places every few months to do a number of aircraft so travelling expenses are shared. 

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18 hours ago, skippydiesel said:

BillLipson,

 

Maaat! If you were in NSW I could help .

 

I suggest ;

You contact your local flying clubs.

Google radio/transponder services in Qld

Who do you use, @skippydiesel? Need to get the RV done.

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There was a service at Mudgee (Airborne Avionics) -no longer BUT they will refer you to their past employee/ technician, who has gone out on his own.

 

Last service (befor aircraft out of test flying) provided by Pacific Avionics , Bankstown - pricy but did the job.

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1 hour ago, skippydiesel said:

There was a service at Mudgee (Airborne Avionics) -no longer BUT they will refer you to their past employee/ technician, who has gone out on his own.

 

Last service (befor aircraft out of test flying) provided by Pacific Avionics , Bankstown - pricy but did the job.

Thanks Skip, have it in my mind a mate out at Narromine used the Mudgee folks for his test a couple years ago, I'll give 'em a call.

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I checked the calibration on mine once using a syringe tee'd into the static line, Iirc 5000' was the highest altitude I could replicate the vacumn force needed to even simulate this mediocre altitude was quite an effort.

 

actually that raises a question....what material are thestatic lines when they enter the pressurised section of an airliner, they must be rather stoutly engineered so as not to collapse with the pressure differential, thick walled stainless tubing I guess or something similar

Actually now I think about it in this day and age  they  are probably electronic pressure sensors outside the pressure shell with just wires to feed the instruments coming inside...but they couldnt do that in the olden day of first generation jetliners

Edited by Red
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Red, there's a somewhat surprising range of materials used in pitot-static lines, and I wouldn't be sure that purely electric/electronic arrangements are used in modern pressurised airliners, there would have to be physical line connections as part of fail-safe systems.

 

WWW.AVIATIONPROS.COM

Pitot-Static Systems Basic for flight By Jim Sparks March 2000 Air is one of the basics needed to support life. In fact for most of us, it is also the basis for our profession...

 

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it takes a bit of time to do because the altitude encoder needs to be walked at a reasonable rate (500 fpm) up AND down from peak altitude, and corresponding transmitter pressure altitude needs to be checked off.

Most seem to use a a climbing 9declining pressure) rate and just watch the dials on the transponder and the instrument pressure generator.   output of the encoder is 100 ft steps.  +/-50' / 125' error,

Per CAO100.5, section 14, refers to Appendix F of FAR part 43

eCFR :: 14 CFR Part 43 -- Maintenance, Preventive Maintenance, Rebuilding, and Alteration (FAR Part 43)

More advanced gear reads the  PA from the decoded, transmitted waveform, and checks for waveform fideltity, timing , which these days will be working, or not.

The two techs I have see use a little buggery box that generates a ping to the transponder next to the aircraft  (a few microwatts) and lists for the return and displays it.

 

for those interested in the other instrument requirements - how to check : and has requirements, tolerable errors etc

, subpart E

eCFR :: Appendix E to Part 43, Title 14 -- Altimeter System Test and Inspection (Appendix E to Part 43, FAR)

 

Edited by RFguy
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6 hours ago, onetrack said:

Red, there's a somewhat surprising range of materials used in pitot-static lines, and I wouldn't be sure that purely electric/electronic arrangements are used in modern pressurised airliners, there would have to be physical line connections as part of fail-safe systems.

 

WWW.AVIATIONPROS.COM

Pitot-Static Systems Basic for flight By Jim Sparks March 2000 Air is one of the basics needed to support life. In fact for most of us, it is also the basis for our profession...

 

Physical tubes are no more failsafe than cables.

I think you mean there needs to be redundancy.

There has to be a pressure tube to the sensor of course but I'm not convinced that any of the current glass cockpit setups use anything other than electronic pressure sensors that wouldn't need to have the sense tube enter the pressurised cockpit or display itself.

The efis in my microlight does have the sensor in the panel but that's non pressurised cockpit of course.

I honestly don't know though, just rambling

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Found this explanation, the presure sensors go to an ADC then from there its an electrical signal to the flight displays, so no need for pitot/static lines inside the pressure hull.

I think any backup instruments are also fully electronic these days

 

 

Oh hold on....further reading indicates the avionics bay that the ADC resides in actually pressurised so that throws out my theory of not needing really strong pressure lines from the static at some point inside the Pressure hull ...doh

 

Anyway Ill stop my rambling nonsense now as it has no relevance to our systems and Im just blurting out stuff as I learn it (shouldnt go posting before my second morning coffee)

Edited by Red
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