RTCA/DO-160 Section 19: Induced Signal Susceptibility

RTCA/DO-160 Section 5 determines performance characteristics of the equipment during temperature variations between high and low operating temperature extremes. Note: The test is not intended to verify the behavior of the equipment in wet or icing conditions. In conducting this test, the test chamber may incorporate the capability of controlling or altering humidity to the extent that condensation is minimized or does not occur. The rates applicable to the temperature variation procedures defined in Subsection 5.3 are as follows: Category A – For equipment external to the aircraft or internal to the aircraft: 10 degrees Celsius minimum per minute. Category B – For equipment in a non-temperature-controlled or partially temperature controlled internal section of the aircraft: 5 degrees Celsius minimum per minute. Category C – For equipment in a temperature-controlled internal section of the aircraft: 2 degrees Celsius minimum per minute. Category S1 – For equipment external to the aircraft or internal to the aircraft: known rate of change greater than 10 degrees Celsius per minute. The rate of change shall be noted in the Qualification Form. Category S2 – For equipment external to the aircraft or internal to the aircraft: unknown rate of change greater than 10 degrees Celsius per minute.

Category A – Standard Humidity Environment Equipment intended for installation in civil aircraft, non -civil transport aircraft and other classes, within environmentally controlled compartments of aircraft in which the severe humidity environment is not normally encountered. Category B – Severe Humidity Environment Equipment installed in zones not environmentally controlled may be required to be operated under conditions such that it is subjected to a more severe atmospheric humidity environment for periods of time in excess of that specified for the standard humidity environment. Category C – External Humidity Environment Equipment may be required to be operated under conditions such that it is subjected to direct contact with outside air for periods of time in excess of that specified for the standard humidity environment.

RTCA/DO-160 Section 8 verifies that equipment can operate or will not be damaged when subjected to vibration levels depending on the installation and location in the aircraft. RTCA/DO-160 Section 8 has many categories of vibration (S, H, Z, and R for Fixed Wing; and R, U and U2 for Helicopter). Depending on the type of aircraft, the location of the unit in the aircraft, and proximity to the engines (based on ‘Zones’) the test levels and durations are determined. 

RTCA/DO-160 Section 10 analyzes how aircraft responds to water under normal conditions and consists of the following tests: Condensing Water Drip Proof Test (Category Y) Drip Proof Test (Category W) Spray Proof Test (Category R) Continuous Stream Proof Test (Category S) Of the four tests, ATEC rents chambers to complete testing for Category Y. This condensing water test requires the use of two temperature and humidity chambers; chamber 1 set to -10° C and chamber 2 set to 40° with 85% relative humidity. The equipment under test is placed (non-operating) into chamber 1 for three hours, then transferred to chamber 2 and operated for 10 minutes. Upon completion, the equipment is evaluated to determine compliance.     Equipment Categories Category Y Equipment that is installed in locations where it is subjected to condensing water in the course of normal aircraft operations. Category W Equipment that is installed in locations where it is subjected to falling water (generally the result of condensation) in the course of normal aircraft operations. Category R Equipment installed in locations where it may be subjected to a driving rain or where water may be sprayed on it from any angle. Category S Equipment installed in locations where it may be subjected to the forces of a heavy stream of fluid such as would be encountered in aircraft de-icing, washing or cleaning operations.

The RTCA/DO-160 Section 15 measures the magnetic effect of the equipment and its main goal is to determine the closest distance to compasses or compass sensors (flux gates) at which that unit is allowed to be installed. RTCA/DO-160 Section 15: Magnetic Effect ensures that equipment can function properly without interference which may affect the nearby equipment, determining equipment compliance with the applicable equipment performance standard or assisting the installer in choosing the proper location of the equipment in the aircraft. The magnetic effect of the equipment is determined in terms of the equivalent deflection of a free magnet in a uniform magnetic field (as produced by the earth) having a horizontal intensity of 14.4 A/m ±10% when the equipment under test is positioned on the east-west line through the pivot of a magnet. These measurements can be performed with either an uncompensated compass or an equivalent magnetic sensor. Category Y: D = 0.0 m. The deflection of the compass is ≤1˚ when measured immediately adjacent to the equipment. This category should be used for equipment whose installation is placed between 0.0 m and 0.3 m from the magnetic compasses or flux gates. Category Z: 0< D ≤ 0.3 m. The deflection of the compass is equal to 1˚ when measured >0.0 m to ≤0.3 m to the equipment. This category should be used for equipment whose installation is ≥ 0.3m to magnetic compasses or flux gates. Category A: 0.3< D ≤ 1 m. The deflection of the compass is equal to 1˚ when measured >0.3 m to ≤1.0 m to the equipment. This category should be used for equipment whose installation is ≥ 1 m to magnetic compasses or flux gates. Category B: 1 m < D ≤ 3 m The deflection of the compass is equal to 1˚ when measured >1.0 m to ≤3.0 m to the equipment. This category should be used for equipment whose installation is ≥3 m to magnetic compasses or flux gates. Category C: The deflection of

RTCA/DO-160 Section 16 test procedures are used to determine whether the EUT can operate during different AC and/or DC power variations that occur during normal and emergency aircraft operation. RTCA/DO-160 Section 16 tests verify whether the equipment will negatively affect the aircraft power system that would be harmful or degrade performance in other equipment. These tests cover both susceptibility (surge, dropout, frequency transients, etc.) and harmful interference (current harmonics, re-generated energy, power factor, etc.) of the EUT.   Tests: DC Input tests Steady-state over- and under-voltage conditions Ripple voltage Momentary power interruption Momentary sags and surges Exposed voltage decay time (270 V only) Inrush current AC Input tests Steady-state over- and under-voltage conditions Steady-state over- and under-frequency conditions Steady-state phase unbalance (three-phase power) Voltage and frequency modulation Voltage and frequency transients Momentary power interruption Momentary sags and surges DC offset and voltage distortion Harmonic current emissions Phase unbalance (3 phase inputs) DC current content Inrush current Current modulation Power factor Equipment Categories According to RTCA/DO-160 Section 16, there are four Equipment Categories (A, B, D, or Z) that indicate the type of power used by the equipment and the type of AC and/or DC power source with which the equipment is compatible. For AC powered equipment, an additional designator, placed in parenthesis following the Category designator, is a two-character code indicating that the equipment has been tested for use with Constant Frequency (CF), Narrow Variable Frequency (NF), or Wide Variable Frequency (WF). Up to four additional category designators are also used to indicate testing for: AC current harmonics (H) AC current modulation (L) AC power factor (P) DC current ripple (R) AC or DC inrush

RTCA/DO-160 Section 17, similar to MIL-STD-461F test method CS106, provides test procedures to determine if the EUT operates as required during and/or after voltage spikes are applied to the AC and/or DC power input(s). Equipment Categories: RTCA/DO-160 Section 17 applies to two categories. Category B test level is twice the AC (rms) and/or DC line voltage (or 200 volts, whichever is less). Category A test level is 600 volts. RTCA/DO-160 provides 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 tests outlined in RTCA/DO-160 Section 17 are performed to meet FAA and international regulations for electrical and electronic equipment installed on commercial aircraft. RTCA/DO-160 G is the current version of this standard. Coordinated with EUROCAE, RTCA/DO-160G and EUROCAE/ED-14G are identically worded. DO-160G is recognized by the International Organization for Standardization (ISO) as de facto international standard ISO-7137. View DO-160 Sec. 17 Set-up Calibration setup serial injection Test setup serial injection Calibration setup parallel injection Test setup parallel injection  

RTCA/DO-160 Section 18 provides test procedures to determine if the EUT will operate as specified when audio frequency interference is applied to the AC and/or DC power input. RTCA/DO-160 Section 18 is similar MIL-STD 461F test method CS101 with the only difference being test level and frequency range. The EUT must be tested while operating at both minimum and maximum current draw (if applicable), and at the AC power frequency extremes if designated for use with Variable Frequency systems when testing to RTCA/DO-160 Section 18 requirements. Equipment Categories There are three DC power Equipment Categories (R, B, and Z) that indicate the type of power used by the equipment and the type of DC power source with which the equipment is compatible. AC Power Equipment Categories are specified as R and K. Category R is used with an additional designation (a two-character code), placed in parenthesis following the Category designator, indicates that the equipment has been tested for use with Constant Frequency (CF), Narrow Variable Frequency (NF), or Wide Variable Frequency (WF). Category K designates that the EUT has been tested for use with any type of AC power input, and tested to a higher level of voltage distortion than category R. RTCA/DO-160 provides 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 tests outlined in this standard are performed to meet FAA and international regulations for electrical and electronic equipment installed on commercial aircraft. RTCA/DO-160 G is the current version of this standard. Coordinated with EUROCAE, RTCA/DO-160G and EUROCAE/ED-14G are identically worded. DO-160G is recognized by the International Organization for Standardization (ISO) as de facto international standard ISO-7137.  

RTCA/DO-160 Section 20 provides test procedures to determine if equipment will operate when the EUT and its interconnecting cables are exposed to Radio Frequency interference. Continuous Wave (CW), Square Wave AM (SW), and Pulse Modulated (PM) RF signals are required. A Line Impedance Stabilization Network (LISN) must be inserted in series with each power lead and ungrounded power return lead, with a 10 uF capacitor connected between the power input of the LISN and the ground plane. RTCA/DO-160 Section 20 has been updated to reflect the requirements of the new FAA rule for High Intensity Radiated Fields testing, also known as HIRF Testing, which is a form of EMC testing applicable to equipment that is subject to extreme electromagnetic environments and/or mission-critical equipment whose failure would be hazardous to human safety. HIRF requirements are applied to ensure that the aircraft electrical and electronic systems can continue safe operation without interruption, failure or malfunction.   Conducted Susceptibility Similar to MIL-STD-461F test method CS114, the RF conducted susceptibility test has the RF interference coupled into the EUT interconnecting cables and power leads using an injection probe calibrated (in a 50 ohm fixture) to the required test level before performing the test. During testing, the RF current induced into the cable or lead under test is monitored with a calibrated RF current probe, and the RF power applied to the injection probe is increased until the appropriate current level (as defined by the applicable Equipment Category used) is reached.   Radiated Susceptibility Similar to MIL-STD-461F test method RS103, the EUT and its interconnecting cables and power leads are exposed to RF radiated fields in the frequency range of 100 MHz to 18 GHz. There two RF radiated susceptibility test methods specified in RTCA/DO-160 Section 20. The first method uses a standard semi-anechoic chamber as in MIL-STD-461F test

The tests in RTCA/DO-160 Section 21 are performed to ensure that the Equipment Under Test (EUT) does not emit Radio Frequency interferences that exceed the specified limits. Conducted RF emissions exposed to interconnecting cables and power leads are measured. Radiated RF emissions from the EUT, power leads and interconnecting cables are also measured.  Measurements must be made with an instrument using a peak detector, and with IF bandwidths, frequency step size, and dwell time as specified in RTCA/DO-160 Section 21, Table 1, for the frequency range being scanned. A Line Impedance Stabilization Network (LISN) must be placed in series with each power lead and ungrounded power return lead, with a 10 uF capacitor connected between the power input of the LISN and the ground plane.  Interconnecting cables should be at least 3.3 meters in length, and power leads will be no more than 1 meter in length for these tests unless otherwise specified.  Ambient emission levels must be at least 6 dB below the applicable limit and must be measured and recorded if any signals are found to be within 3 dB of the applicable limit.   Conducted Emissions Clamp-on current probes are used to measure conducted RF current on interconnecting cables and power leads. The current probe is to be positioned 5 centimeters away from the EUT and measurements are recorded over the frequency range of 150 kHz to 152 MHz.   Radiated Emissions A linearly polarized antenna is used to measure Radiated RF fields over the frequency range of 100 MHz to 6 GHz. As seen in RF radiated susceptibility testing in Section 20, there are two RF radiated emissions test methods allowed in RTCA/DO-160 Section 21: The Reverberation Chamber Method and the Anechoic Chamber method. The Reverberation Chamber method which requires a Field Uniformity Validation from Section 20. After the EUT is installed in the chamber, EUT Loading is measured, and this data is used as a

RTCA/DO-160 Section 22 offers test procedures to determine whether the EUT can operate as specified during and/or after various lightning induced transient waveforms are injected into connector pins, interconnecting cables, and power leads using pin injection, and/or cable bundle tests. The pin injection method is normally used to show damage tolerance, while the cable bundle tests are normally used to show upset tolerance. Pin Injection During pin injection testing, the EUT is normally powered, so that the circuits being tested are biased as they would be in normal operation. The test level is defined as an open circuit voltage (Voc) with a specified source impedance from the generator. Cable Bundle Tests Cable Bundle Tests are performed using either Cable Induction or Ground Injection to couple the transient waveforms into the interconnecting cable bundles and power leads. The cable induction test method uses an injection probe to induce the transient waveforms into interconnecting cables and power leads. The ground injection method is very similar to the cable induction method, except that the transient waveform is applied between the EUT case and the ground plane. Cable Bundle tests for RTCA/DO-160 Section 22 may be performed using the Single Stroke method only or using a combination of the Single Stroke, Multiple Stroke, and Multiple Burst methods. The Single Stroke test method is designed to represent the internal aircraft wiring response to the most severe external aircraft lightning strike. The Multiple Stroke test method is designed to represent the induced effects to internal aircraft wiring in response to an external aircraft lightning strike that is composed of a first return stroke immediately followed by multiple return strokes. The Multiple Burst test method is designed to represent the induced effects to internal aircraft wiring in response to an external aircraft lightning strike of a multiple burst nature. Equipment

The tests in RTCA/DO-160: Section 23 are intended to determine the ability of externally mounted equipment to withstand the direct effects of a lightning strike. The term “externally mounted equipment” refers to all equipment mounted externally to the main skin of the aircraft and includes all such equipment that is covered only by a dielectric skin or fairing that is an integral part of the equipment. It also includes connecting cables and associated terminal equipment furnished by the equipment manufacturer as a part of the equipment. The tests described in RTCA/DO-160 Section 23: Lightning Direct Effects specifically exclude the effects on the tested equipment of voltages and currents induced into the externally mounted equipment and its associated circuitry utilizing magnetic or electric field coupling. Some examples of equipment covered by this section are exterior lights, antennas, external sensors, air data probes, and anti-ice and de-ice equipment, each of which are mounted external to the structure (i.e. electrically heated anti-ice boots), magnetic fluid level indicators, fuel filler caps, and drain valves. Examples of equipment typically not covered by this section are equipment that is integral to the aircraft structure (i.e., heated or unheated windshields, electrically de-iced leading edges where the de-ice system is an integral part of the leading edge structure or is enclosed by the leading edge structure), and externally mounted equipment that is protected by aircraft nose radomes or dielectric coverings which are specific to the aircraft structure and are not integral with the equipment itself. Components such as these typically are to be addressed and/or tested as a part of the air-frame lightning certification program specified by the aircraft manufacturer, or by other test method(s) appropriate to the component being qualified. Two types of direct effects tests are contained in the section: High voltage strike

This test determines whether the EUT can operate as specified during and after being subjected to an electrostatic air discharge event. Both the test procedure and test generator used are similar to most other international ESD standards, except that the EUT is bonded to the ground plane and only air discharge is specified. Test points are chosen based on their accessibility to personnel, with 10 positive and 10 negative polarity discharges at 15 kV applied to each one. Equipment Categories There is only one category (A), with a test level of 15 kV. RTCA/DO-160 provides 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 tests outlined in this standard are performed to meet FAA and international regulations for electrical and electronic equipment installed on commercial aircraft. RTCA/DO-160 G is the current version of this standard. Coordinated with EUROCAE, RTCA/DO-160G and EUROCAE/ED-14G are identically worded. DO-160G is recognized by the International Organization for Standardization (ISO) as de facto international standard ISO-7137.   Changes between DO-160 D, E, F, and G From C to D From D to E From E to F From F to G A new section was added to address device level susceptibility issues for ESD. No significant changes were made. No significant changes were made, except correcting typographical errors in the figures.   Added note that ESD connection point is not applicable to connector pins. Added expansion of type and of the list of test points to be considered. Address case of no discharge.   More On ESD Testing     Recommended Bundle For All 30kV Regulated