EMI/EMC Requirements for

Part 23/25 Airplanes

Jean Cartier Avionics Workshop

TCCA Aircraft Certification November 27, 2003

AEA 03-03 Item

EMI/EMC Testing

of

Avionics Modifications

Statement of Issue

AEA recommends TCCA to provide guidance material to ensure EMI/EMC testing of avionics installations are conducted in a manner appropriate to the type and criticality of equipment being installed and its potential effects on the aircraft

AEA Issues

Level of EMC Testing for Non-required Equipment Installations

DO-160D Section 20/21 Test Category/Data for Criticality of Equipment and Functions

Compliance to HIRF Certification Standards Requirements for EMC Test Plans Acceptability of Equipment Test Data VS

Installation Test Data

§ 23.1431(b)Electronic Equipment

(b) Radio and electronic equipment, controls, and wiring must be installed so that operation of any 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.

§23.1431(b) parallels the requirement of §23.1309(a) The intent of § 23.1431(b) is exactly the same as

§25.1431(c) Issued 11/03/64 & CAR 4b.650, 31/12/53

Level of EMC Testing for NRE Installations

General guidelines for EMC are provided in:AC 25-10 “Guidance for Installation of Miscellaneous, Non-required Electrical Equipment”

MIL-STD 464 “Electromagnetic Environmental Effects Requirements for Systems”

AC 43.13-1B “Guidance for Installation of Miscellaneous, Non-required Electrical Equipment” Chapter 11, Paragraphs 106/107

Level of EMC Testing forNRE Installations (Cont’d)

The following factors should be addressed as part of the EMC requirements:Verify by inspection that the installed equipment/system conforms to

the specified installation drawingsDevelopment of the source/victim operational check matrix should

consider potential EMI conditions between transmission and harmonic frequencies of required equipment such as radios and navigation systems, Etc…

All reasonable combinations of control settings and operating modes should be assessed

Communications and navigation equipment should be operated on low, mid-band, and high frequencies

Level of EMC Testing forNRE Installations (Cont’d)

The following factors should be addressed as part of the EMC requirements (Cont’d):All electrically operated equipment and systems must be fully

functional In-Flight EMC testing should be assessed to validate flight

operated functions which cannot be assessed on-groundOn-Ground EMC testing should be conducted with the equipment

powered by the airplanes’s electrical generating system

Level of EMC Testing forNRE Installations (Cont’d)

The following factors identify installation design considerations which may directly contribute to the quality of EMC between non-required and required A/C systems:Equipment location and installation

Harness routing

Shielding integrity

Wiring segregation

Potential ground loops

Inter-channel communication interference

Antenna Radiation

Level of EMC Testing forNRE Installations (Cont’d)

The source/victim testing level for non-required equipment is the same as for required equipment.However, our concern is much less for the functionality of non-required equipment

DO-160D Section 20 Test Category/Data for Criticality of Equipment and Functions

RF Susceptibility (Radiated & Conducted)

The purpose of section 20 is to determine that the equipment functions will not be adversely affected when the equipment and its interconnecting wiring are exposed to specified HIRF levels

The declared equipment test category level should comply with the HIRF’s Special Condition (SC) requirements

Applicable to systems which perform critical functions

DO-160D Section 21 Test Category/Data for Criticality of Equipment and Functions

Emission of RF Energy (Radiated & Conducted)

The purpose of section 21 is to determine that the equipment does not emit undesired RF noise in excess of the specified test category level.

DO-160D section 21 provides guidance for selecting appropriate category levels

The test category levels are declared by the equipment manufacturer

DO-160D Section 21 Test Category/Data for Criticality of Equipment and Functions

(Cont’d)

DO-160 provides guidance to assist the manufacture in selecting the appropriate test category. However, it is the responsibility of the installer to resolve any incompatibilities between the new installation and previously installed equipment

Compliance to HIRF Certification Standards

The following are applicable guidance/advisory material:– FAA Notice N8110.71 “Guidance for the Certification of Aircraft

Operating in HIRF Environments” 4/2/98– AC/AMJ 20-1317 “The Certification of Aircraft Electrical and

Electronic Systems for Operation in the HIRF Environment” – “Final Draft” March 1999

– Users Guide for AC/AMJ 20-1317 “The Certification of Aircraft Electrical and Electronic Systems”

– SAE ARP5583 “Guide to Certification of Aircraft in a HIRF Environment” January 2003

– DO-160D Section 20 “RF Susceptibility (Radiated and Conducted)14/12/00 Change No. 1

Compliance to HIRF Certification Standards(Cont’d)

The requirement for certification to HIRF is addressed by a Special Condition (SC), and is applicable to systems which perform critical (Level A) functions

Compliance to the HIRF SC requires that the applicant submit the following:Compliance Plan outlining the method of compliance to HIRF Aircraft Hazard/Safety Analysis (FHA) and a HIRF/Lightning

Criticality Assessment to substantiate the systems/equipment criticality levels and test data

Compliance to HIRF Certification Standards(Cont’d)

The FAA/TCCA HIRF SC requirements are applicable only to systems which perform critical functions (Level A)

The JAA HIRF SC requirements are applicable to systems which performs critical and essential functions (Levels A,B,C)

Compliance to HIRF Certification Standards (Cont’d)

Also applicable to the HIRF SC is the requirement to provide Instructions for Continued Airworthiness (ICAW) in accordance with the requirement of §23/25.1529.

The ICAW should include all necessary maintenance actions to assure that the continued integrity of structural shielding, wire shields, connectors, and equipment protection components are maintained

Need for EMC Test Plans

An EMC test plan is required to document:The source/victim functional test matrix

(Evaluation of all potential system victims must be assessed)The equipment/system installation conformity

(A/C equipment/system configuration must be representative; model and part number of the installed equipment should be identified)

The Pass/Fail criteria (as applicable)All reasonable combinations of control settings and operating

modes (All foreseeable EMC worst case conditions should be considered)

Need for EMC Test Plans (Cont’d)

An EMC test plan is required to document: (Cont’d)

Communication and navigation equipment operating frequencies

On-ground and In-flight test configurations

The test plan should provide adequate detail to assure repeatability

Acceptability of Equipment Test Data VS Installation Test Data

DO-160 Section 20 equipment test data would be acceptable providing that the test category levels comply with the HIRF SC requirements (Category W; 100V/M - 150mA)

DO-160 Section 21 equipment test data would not be sufficient(section 21 qualification test data provides some degree of confidence to the installer that the equipment will be compatible with installed systems) However, EMC A/C installation test data would be required to demonstrate compliance to §23/25.1431

Conclusion

All new installations must address the requirements of §23.1431(b)/§25.1431(c)

Recommended guidance material is provided in AC 25-10, MIL-STD 464, AC 43.13-1B, and the HIRF users guide

TCCA intends to address EMI/EMC concerns at the internal TCCA workshop