EMI/EMC Test Matrix
Thread Starter
EMI/EMC Test Matrix
Greetings,
I have been given the opportunity to update our EMI/EMC flight test plans. We are required to demonstrate freedom from adverse interference between simultaneously operated systems. These systems include the installed avionics, cabin entertainment, galley and lavatory systems.
I have reviewed numerous ground/flight test plans (from our own organization) and they run the gamut; some are quite sparse while other are rather in-depth.
BTW, we install full interior completions in Part 25 airplanes. We certify/validate to both FAR/JAR requirements. As I mentioned, this is an opportunity to improve our process. My goal is to provide a repeatable procedure that meets the requirements without going overboard.
Any suggestions or matrix examples would be greatly appreciated.
Thanks much,
Tweedles
I have been given the opportunity to update our EMI/EMC flight test plans. We are required to demonstrate freedom from adverse interference between simultaneously operated systems. These systems include the installed avionics, cabin entertainment, galley and lavatory systems.
I have reviewed numerous ground/flight test plans (from our own organization) and they run the gamut; some are quite sparse while other are rather in-depth.
BTW, we install full interior completions in Part 25 airplanes. We certify/validate to both FAR/JAR requirements. As I mentioned, this is an opportunity to improve our process. My goal is to provide a repeatable procedure that meets the requirements without going overboard.
Any suggestions or matrix examples would be greatly appreciated.
Thanks much,
Tweedles
Moderator
Well Tweedles,
The lack of responses here would appear to be an indication of the lack of uniform soulution to this requirement. I am required to witness these tests frequently for the approval of modifications involving electronic equipment. I have yet to see a consistend approach. I have seen really advanced looking hand held wands used, but much more frequently, and my approach, just turning everything on and off in a documented sequence, and watching and listening for a preceptable change. I have asked Tranpsort Canada for guidance or a reference to what is a correctly conducted EMI test, and the answer was that there is no standard test. How then can I find compliance to a design standard, when there is no standard?!
The best I have seen was a completely thorough matrix of all systems, on an aircraft I recently modded in Hong Kong. That organization had put a lot of thought into it, but not relative to any standard for such a test.
So good luck... Avionics people (which I am most certainly not) will have a better idea than I, as to what a conclusive EMI test would be. As for a standardized one... I'll keep watching this thread, maybe I can learn something!
Pilot DAR
The lack of responses here would appear to be an indication of the lack of uniform soulution to this requirement. I am required to witness these tests frequently for the approval of modifications involving electronic equipment. I have yet to see a consistend approach. I have seen really advanced looking hand held wands used, but much more frequently, and my approach, just turning everything on and off in a documented sequence, and watching and listening for a preceptable change. I have asked Tranpsort Canada for guidance or a reference to what is a correctly conducted EMI test, and the answer was that there is no standard test. How then can I find compliance to a design standard, when there is no standard?!
The best I have seen was a completely thorough matrix of all systems, on an aircraft I recently modded in Hong Kong. That organization had put a lot of thought into it, but not relative to any standard for such a test.
So good luck... Avionics people (which I am most certainly not) will have a better idea than I, as to what a conclusive EMI test would be. As for a standardized one... I'll keep watching this thread, maybe I can learn something!
Pilot DAR
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I think one of the reasons why EMI testing doesn't have many rules is that it's so effected by the configuration & equipment fit of the aircraft. For example, analog aircraft with HF used to be an EMI nightmare but with digital instrumentation like EICAS, with its built-in filtering, and the "cleaner" modern transmitters I haven't had any significant EMI problems during test for years.
Some very general guidelines would include do a full ground EMI test, one in cruise and one on approach; cover the full range & modes of all your radios and don't forget to check you don't have any problems on FDR & CVR (download after flight). If you're doing completions, you probably know well that you can get as much or more interference from the entertainment system so wring that out as well - including using all the kit while tracking an ILS - you know the boss will do it even if the book says not to.
Some very general guidelines would include do a full ground EMI test, one in cruise and one on approach; cover the full range & modes of all your radios and don't forget to check you don't have any problems on FDR & CVR (download after flight). If you're doing completions, you probably know well that you can get as much or more interference from the entertainment system so wring that out as well - including using all the kit while tracking an ILS - you know the boss will do it even if the book says not to.
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I'm not pretending to be a Guru but the following standards may cover what you are looking for,
DO-160E, Environmental Conditions and Test Procedures for Airborne Equipment
Issued 12-09-04 s Supersedes DO-160D, Changes 1, 2 & 3 s Prepared by SC-135
Standard procedures and environmental test criteria for testing airborne equipment for the entire spectrum of aircraft from light general aviation aircraft and helicopters through the “Jumbo Jets” and SST categories of aircraft. The document includes 26 Sections and three Appendices. Examples of tests covered include vibration, power input, radio frequency susceptibility, lightning, and electrostatic discharge. Coordinated with EUROCAE, RTCA/DO-160E and EUROCAE/ED-14E are identically worded. This revision updates 22 Sections and adds one new Section – Fire, Flammability.
DO-160E is recognized by the International Organization for Standardization (ISO) as de facto international standard ISO-7137.
TMAB
DO-160E, Environmental Conditions and Test Procedures for Airborne Equipment
Issued 12-09-04 s Supersedes DO-160D, Changes 1, 2 & 3 s Prepared by SC-135
Standard procedures and environmental test criteria for testing airborne equipment for the entire spectrum of aircraft from light general aviation aircraft and helicopters through the “Jumbo Jets” and SST categories of aircraft. The document includes 26 Sections and three Appendices. Examples of tests covered include vibration, power input, radio frequency susceptibility, lightning, and electrostatic discharge. Coordinated with EUROCAE, RTCA/DO-160E and EUROCAE/ED-14E are identically worded. This revision updates 22 Sections and adds one new Section – Fire, Flammability.
DO-160E is recognized by the International Organization for Standardization (ISO) as de facto international standard ISO-7137.
TMAB
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Balloon,
DO-160 is a guide/standard for bench testing individual avionics units - EMC deals more with the interaction between units & systems. Unfortunately equipment can meet every test in DO-160 but still be a bad source of interference.
DO-160 is a guide/standard for bench testing individual avionics units - EMC deals more with the interaction between units & systems. Unfortunately equipment can meet every test in DO-160 but still be a bad source of interference.
Thread Starter
Thank you Pilot DAR, ICT SLB and TMAB for your replies. I apologize for not getting a reply out to you sooner.
I have incorporated much of what you have suggested, Pilot DAR and ICT SLB. TMAB, in referencing DO-160, I too believe that it is geared towards laboratory testing of airborne equipment. My task is to verify how all the equipment acts when operated together.
Our legacy test plan format had us turn everything on and provided little direction once that was done. I borrowed a format that has been used elsewhere in our organization; this format segregated our completion equipment into sections of the cabin. This allows us to check for EMI in a somewhat logical manner.
We check newly installed completion systems against flight deck systems, the new systems against each other, and also check for interference in completion systems due to flight deck system operation. I added directions on modes of operation to be checked as well as space to record transmit frequencies where appropriate. I believe these changes will make this procedure more thorough and also easier to use – time will tell.
I also found AC25-7A and AC25-10 to be helpful in determining just what is required - or more appropriately, what methods have previously been found to be acceptable.
Regarding downloading FDR and CVR data - I'm looking into this as that is something I have not seen done here. Currently the CVR mic is monitored via headset.
Again, I appreciate your taking the time to reply. Your insights helped give me the confidence that I wasn't "all wet" with some of my suggested changes.
Take care,
Tweedles
I have incorporated much of what you have suggested, Pilot DAR and ICT SLB. TMAB, in referencing DO-160, I too believe that it is geared towards laboratory testing of airborne equipment. My task is to verify how all the equipment acts when operated together.
Our legacy test plan format had us turn everything on and provided little direction once that was done. I borrowed a format that has been used elsewhere in our organization; this format segregated our completion equipment into sections of the cabin. This allows us to check for EMI in a somewhat logical manner.
We check newly installed completion systems against flight deck systems, the new systems against each other, and also check for interference in completion systems due to flight deck system operation. I added directions on modes of operation to be checked as well as space to record transmit frequencies where appropriate. I believe these changes will make this procedure more thorough and also easier to use – time will tell.
I also found AC25-7A and AC25-10 to be helpful in determining just what is required - or more appropriately, what methods have previously been found to be acceptable.
Regarding downloading FDR and CVR data - I'm looking into this as that is something I have not seen done here. Currently the CVR mic is monitored via headset.
Again, I appreciate your taking the time to reply. Your insights helped give me the confidence that I wasn't "all wet" with some of my suggested changes.
Take care,
Tweedles
You should give consideration to validating the operational conditions of all components prior to running the test matrix. If a particular item is defective or component/wiring prevents operation at rated power, the results would be inconclusive.
I have been involved with an aircraft that had significant EMI/EMC issues. Execution of the actual matrix was quick and easy, however the setup/troubleshooting took weeks.
I have been involved with an aircraft that had significant EMI/EMC issues. Execution of the actual matrix was quick and easy, however the setup/troubleshooting took weeks.
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MIG,
So would I! My guess is that the majority of current installations are STCs and thus often held to a lower standard than a system installed as OEM. This has been a bone of contention with the authorities - especially when they just don't have the expertise available at the local level.
Not strictly aircraft EMC, but I once got involved with an ILS interefence issue at a European airport. When the Flight Inspection checks were carried out after hours, there were no effects recorded but aircraft had glideslope issues (backed up by data analysis) during peak periods. My suspicion was that a mobile phone tower was causing the problem, which disappeared as phone traffic wound down.
So would I! My guess is that the majority of current installations are STCs and thus often held to a lower standard than a system installed as OEM. This has been a bone of contention with the authorities - especially when they just don't have the expertise available at the local level.
Not strictly aircraft EMC, but I once got involved with an ILS interefence issue at a European airport. When the Flight Inspection checks were carried out after hours, there were no effects recorded but aircraft had glideslope issues (backed up by data analysis) during peak periods. My suspicion was that a mobile phone tower was causing the problem, which disappeared as phone traffic wound down.
