Interpretation of AC25-10 Non-required Electrical Equipment Guidance 1

[Onwing]

AC 25-10 is the guidance to certify those Non-required Electrical Equipment Guidance.

I wanna to install a FAX machine onto FAR-25 aircraft.

This Fax machine is classified as "Non-required" and is not an aircraft part.

AC 25-10 para 5.f. says EMI test, IF REQUIRED, must have been performed iaw DO-160.

How do I know what is IF REQUIRED situation, does DO-160 is mandatory?

 

[debodine]

Ultimately the decision of what is required is the province of the FAA team or their designees as to what is necessary to return the aircraft to service. However, some FAR references (not a comprehensive list) that would be good to review so you would know what they look for would be:

FAR 25.1301(a) Each item of installed equipment must be of a kind and design appropriate to its intended function. (My comment: If it radiates EMI like an antenna, maybe you don't want it on the aircraft.)

FAR 25.1301(d) Each item of installed equipment must function properly when installed. (My comment: If certain operational modes result in EMI release that could be consequential.)

FAR 25.1353(a) Electrical equipment, controls and wiring must be installed so that operation of any one unit or system of units will not adversely affect the simultaneous operation of any other electrical unit or system essential to the safe operation. (My comment: This one for electrical and the next one for electronic cover any situation where operation of the fax might interfere with onboard systems.)

FAR 25.1431(c) Radio and electronic equipment, controls and wiring must be installed so that operation of any one unit or system of units will not adversely affect the simultaneous operation of any other radio or electronic unit, or system of units, required by this chapter.

Any of the above FAR requirements may trigger an EMI test as well as a few other FAR references that I did not have close at hand.

Additional information: Equipment that is manufactured to an FAA TSO (Technical Standard Order) has passed DO-160 testing that verifies the item is within the limits of standardized testing categories. A fax machine that has not been manufactured specifically for aircraft use has not likely been tested to DO-160. This brings added pressure on the FAA/designee team to have a method to insure the fax machine complies with the above FAR references and others.

I am NOT a DER but I would guess in your case an EMI test would be mandatory. The only case where it might not be would be if the fax machine were installed in such a manner that it is impossible to activate it during flight and it can only be used on the ground. Even then if it radiates EMI it could possibly interfere with instrumentation checks during the flight crew preflight and flight deck setup prior to launch. So even in that case the FAA/designee may require an EMI test.

Again I am not a DER so the above is experience only from an outside viewpoint. Only an FAA person or an appropriately rated DER can give you authoritative info, probably from the FAA guidance handbooks which likely address such issues.

Installing faxes can be done (we have done it) but I don't recall a case where we could without an EMI test.

 

[Onwing]

Thanks for your reply.

For the Fax machine is to be installed to a VIP aircraft, it should be operational during cruise. And iaw AC25-10, such Fax machine should be housed in a metal enclosure. However, the metal enclosure cover/door may be opened during flight. So the EMI test is mandatory to fulfill the FAR 25.1353(a) and 25.1431(c).

The EMI test has component level (DO-160E Para 21.0 Emission of RF Energy) and aircraft level(within STC test plan). The latter is obviousely mandatory.

Now it seems the component level Category M EMI test is also required (Ref DO-160E Para 21.3 Conducted RF Emission and 21.4 Radiated RF Emission).

Onwing

 

[debodine]

It appears you have a clear grasp of the situation now. I am glad I was able to provide a bit of assistance.

 

[Onwing]

Thanks Debodine, after your guidance, I am clear of the direction. But some details of certification is still unknow, as indicated in my another thread.
Thanks again.
Onwing