CS-27 D27 HIRF Environments and Equipment HIRF Test Levels

This Appendix specifies the HIRF environments and equipment HIRF test levels for electrical and electronic systems under CS 27.1317. The field strength values for the HIRF environments and equipment HIRF test levels are expressed in root-mean-square units measured during the peak of the modulation cycle. (a) HIRF environment I is specified in the following table: Table I — HIRF Environment I 10 kHz–2 MHz 2–30 MHz 100–400 MHz 400–700 MHz 700 MHz–1 GHz 1–2 GHz 2–6 GHz 6–8 GHz 8–12 GHz 12–18 GHz 18–40 GHz FIELD STRENGTH (V/m) PEAK AVERAGE 50 50 100 100 100 100 700 50 700 100 2000 200 3000 200 1000 200 3000 300 2000 200 600 200 In this table, the higher field strength applies to the frequency band edges. (b) HIRF environment II is specified in the following table: Table II — HIRF Environment II 10–500 kHz 500 kHz–2 MHz 2–30 MHz 30–100 MHz 100–200 MHz 200–400 MHz 400 MHz–1 GHz 1–2 GHz 2–4 GHz 4–6 GHz 6–8 GHz 8–12 GHz 12–18 GHz 18–40 GHz FIELD STRENGTH (V/m) PEAK AVERAGE 20 20 30 30 100 100 10 10 30 10 10 10 700 40 1300 160 3000 120 3000 160 400 170 1230 230 730 190 600 150 In this table, the higher field strength applies to the frequency band edges. (c) HIRF environment III is specified in the following table: Table III — HIRF Environment III 10–100 kHz 100 kHz–400 MHz 400–700 MHz 700 MHz–1 GHz 1–2 GHz 2–4 GHz 4–6 GHz 6–8 GHz 8–12 GHz 12–18 GHz 18–40 GHz FIELD STRENGTH (V/m) PEAK AVERAGE 150 150 200 200 730 200 1400 240 5000 250 6000 490 7200 400 1100 170 5000 330 2000 330 1000 420 In this table, the higher field strength applies at the frequency band edges. (d) Equipment HIRF Test Level 1 (1) From 10 kilohertz (kHz) to 400 megahertz (MHz), use conducted susceptibility tests with continuous wave (CW) and 1 kHz square wave modulation with 90 % depth or greater. The conducted susceptibility current must start at a minimum of 0.6 milliamperes (mA) at 10 kHz, increasing 20 decibels (dB) per frequency decade to a minimum of 30 mA at 500 kHz. (2) From 500 kHz to 40 MHz, the conducted susceptibility current must be at least 30 mA. (3) From 40 MHz to 400 MHz, use conducted susceptibility tests, starting at a minimum of 30 mA at 40 MHz, decreasing 20 dB per frequency decade to a minimum of 3 mA at 400 MHz. (4) From 100 MHz to 400 MHz, use radiated susceptibility tests at a minimum of 20 volts per meter (V/m) peak with CW and 1 kHz square wave modulation with 90 % depth or greater. (5) From 400 MHz to 8 gigahertz (GHz), use radiated susceptibility tests at a minimum of 150 V/m peak with pulse modulation of 4 % duty cycle with 1 kHz pulse repetition frequency. This signal must be switched on and off at a rate of 1 Hz with a duty cycle of 50 %. (e) Equipment HIRF Test Level 2. Equipment HIRF Test Level 2 is HIRF environment II in Table II of this Appendix reduced by acceptable aircraft transfer function and attenuation curves. Testing must cover the frequency band of 10 kHz to 8 GHz. (f) Equipment HIRF Test Level 3 (1) From 10 kHz to 400 MHz, use conducted susceptibility tests, starting at a minimum of 0.15 mA at 10 kHz, increasing 20 dB per frequency decade to a minimum of 7.5 mA at 500 kHz. (2) From 500 kHz to 40 MHz, use conducted susceptibility tests at a minimum of 7.5 mA. (3) From 40 MHz to 400 MHz, use conducted susceptibility tests, starting at a minimum of 7.5 mA at 40 MHz, decreasing 20 dB per frequency decade to a minimum of 0.75 mA at 400 MHz. (4) From 100 MHz to 8 GHz, use radiated susceptibility tests at a minimum of 5 V/m.