Aerospace and MIL-STD EMC (MIL-STD-461, DO-160)
How EMC requirements for MIL-STD-461 and airborne equipment differ from commercial ones: MIL-STD-461 test codes, MIL-STD-464, RTCA DO-160 and EUROCAE ED-14.
MIL-STD and aerospace EMC differs from commercial EMC in three ways: the requirements are contractual rather than legal, the frequency ranges and levels are broader, and the consequences of interference (loss of a mission, a flight-safety event) are more severe.
MIL-STD-461: equipment level
MIL-STD-461 (current revision G) sets the interface and requirement limits for the electromagnetic interference characteristics of subsystems and equipment, and the test methods. Requirements are identified by codes with a prefix that tells the type:
- CE conducted emissions, CS conducted susceptibility,
- RE radiated emissions, RS radiated susceptibility.
Examples (the exact applicability depends on the platform and is chosen in the contract):
| Code | Subject (summary) |
|---|---|
| CE101 / CE102 | Conducted emissions on power leads (low frequency and 10 kHz–10 MHz) |
| CS101 | Conducted susceptibility, power leads (low-frequency ripple) |
| CS114 | Bulk cable injection (RF current on cable bundles) |
| CS115 / CS116 | Impulse excitation and damped sinusoidal transients on cables and power leads |
| RE101 / RE102 | Radiated emissions of magnetic field (low frequency) and electric field (up to 18 GHz) |
| RS101 / RS103 | Radiated susceptibility to magnetic fields and to electric fields |
Test set-ups use a 5 µH line impedance stabilisation network and a ground plane; cables are specified by length and routing.
MIL-STD-464: system level
MIL-STD-464 covers electromagnetic environmental effects for complete systems: platform-level compatibility, lightning, electrostatic charge, electromagnetic pulse and spectrum considerations, bonding and grounding, and hazards of electromagnetic radiation to ordnance, fuel and personnel.
RTCA DO-160 and EUROCAE ED-14: airborne equipment
RTCA DO-160 (identical in intent to the European EUROCAE ED-14) defines environmental conditions and test procedures for airborne equipment. Its EMC sections include:
- magnetic effect (the effect of a device on a compass),
- power input, voltage spike, audio-frequency conducted susceptibility and induced signal susceptibility,
- radio-frequency susceptibility (radiated and conducted) and emission of radio-frequency energy,
- lightning-induced transient susceptibility and lightning direct effects,
- electrostatic discharge.
Test categories (letters and numbers) classify the equipment by installation location and the severity required; the airframe manufacturer and the certification authority state which apply.
Differences from commercial EMC
| Commercial | MIL-STD/aerospace | |
|---|---|---|
| Legal basis | Regulation in the market | Contract or certification basis |
| Frequency range | Mainly 150 kHz–6 GHz | From low frequencies (power-frequency harmonics) to 18 GHz and beyond |
| Immunity levels | Chosen for the environment | Often higher, with defined fields and currents |
| Cables | Typical cable lengths | Defined lengths, routing, shielding and bonding |
| Bonding and grounding | Safety grounding | Defined bonding resistance and procedures |
Where to check
The contract or certification basis names the standard, the revision and the tailoring. Use the official sources (the US government’s ASSIST standards database, RTCA and EUROCAE) for the current revisions.