14 CFR Appendix D to Part 27 - Appendix D to Part 27—HIRF Environments and Equipment HIRF Test Levels

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Appendix D to Part 27—HIRF Environments and Equipment HIRF Test Levels

This appendix specifies the HIRF environments and equipment HIRF test levels for electrical and electronic systems under § 27.1317. The field strength values for the HIRF environments and laboratory 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

Frequency Field strength
(volts/meter)
Peak Average
10 kHz–2 MHz 50 50
2 MHz–30 MHz 100 100
30 MHz–100 MHz 50 50
100 MHz–400 MHz 100 100
400 MHz–700 MHz 700 50
700 MHz–1 GHz 700 100
1 GHz–2 GHz 2,000 200
2 GHz–6 GHz 3,000 200
6 GHz–8 GHz 1,000 200
8 GHz–12 GHz 3,000 300
12 GHz–18 GHz 2,000 200
18 GHz–40 GHz 600 200

In this table, the higher field strength applies at the frequency band edges.

(b) HIRF environment II is specified in the following table:

Table II.—HIRF Environment II

Frequency Field strength
(volts/meter)
Peak Average
10 kHz–500 kHz 20 20
500 kHz–2 MHz 30 30
2 MHz–30 MHz 100 100
30 MHz–100 MHz 10 10
100 MHz–200 MHz 30 10
200 MHz–400 MHz 10 10
400 MHz–1 GHz 700 40
1 GHz–2 GHz 1,300 160
2 GHz–4 GHz 3,000 120
4 GHz–6 GHz 3,000 160
6 GHz–8 GHz 400 170
8 GHz–12 GHz 1,230 230
12 GHz–18 GHz 730 190
18 GHz–40 GHz 600 150

In this table, the higher field strength applies at the frequency band edges.

(c) HIRF environment III is specified in the following table:

Table III.—HIRF Environment III

Frequency Field strength
(volts/meter)
Peak Average
10 kHz–100 kHz 150 150
100 kHz–400 MHz 200 200
400 MHz–700 MHz 730 200
700 MHz–1 GHz 1,400 240
1 GHz–2 GHz 5,000 250
2 GHz–4 GHz 6,000 490
4 GHz–6 GHz 7,200 400
6 GHz–8 GHz 1,100 170
8 GHz–12 GHz 5,000 330
12 GHz–18 GHz 2,000 330
18 GHz–40 GHz 1,000 420

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 percent 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 percent 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 percent duty cycle with a 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 percent.

(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.

[Doc. No. FAA–2006–23657, 72 FR 44027, Aug. 6, 2007]