MOC 2 VTOL.2500(b) Electromagnetic compatibility

• n/a found in: Small Category VCA (Revision 0) SC-VTOL (Oct 2024)

MOC 2 VTOL.2500(b) Electromagnetic compatibility n/a **1. Introduction and scope** This MOC provides an accepted means of compliance related to Electromagnetic Compatibility (EMC) between different equipment and also between equipment and its interconnecting cabling. It is applicable to VTOL capable Aircraft in Categories Basic and Enhanced. **2. Electromagnetic compatibility** Electromagnetic compatibility tests should be conducted on the ground and in- flight as necessary. Any electromagnetic interference (EMI) noted on the ground should be repeated in- flight at the frequency at which the EMI occurred on the ground, unless the problem could be analysed and resolved beforehand. Since some systems are difficult to operate on the ground (e.g. air data system, etc.), the effects of EMI should be evaluated with all systems operating in- flight to verify that no adverse effects are present in the engine, energy supply system control, battery management, brake antiskid and other systems. When electromagnetic interference and radio frequency interference (EMI and RFI) protection is required, special attention should be paid to the termination of individual and overall shields. Back shell adapters that are designed for shield termination, connectors with conductive finishes, and EMI grounding fingers are available for this purpose as are many other suitable solutions. Electromagnetic interferences can exist between systems, but also between wires, and between wires and systems. Electromagnetic interference can be introduced into aeroplane systems and wiring by coupling between electrical cables or between cables and coaxial lines or other aeroplane systems. The correct functioning of systems should not be affected by EMI generated by adjacent wires. EMI between wiring which is a source of EMI and wire susceptible to EMI increases in proportion to the length of parallel runs and decreases with greater separation. Wiring of sensitive circuits that may be affected by EMI should be routed away from other wiring interference or provided with sufficient shielding to avoid system malfunctions under operating conditions. Regardless of the function performed, the equipment and its interconnecting wiring will unavoidably generate and be exposed to various types of electrical transients, electrical and magnetic fields, and spurious noise, spanning over a wide range of frequencies and amplitudes. For sure, EMI should be limited to negligible levels in wiring related to systems that are necessary for continued safe flight, landing and egress. A comprehensive victim and source testing is typically expected to ensure the proper functioning of the systems on the aircraft (unless another way is agreed with the Agency). The following sources of interference should be considered: (a) Conducted and radiated interference caused by electrical noise generation from apparatus connected to the busbars. (b) Coupling between electrical cables or between cables and aerial feeders. (c) Parasitic currents and voltages in the electrical distribution and grounding systems, including the effects of lightning currents or static discharge. (d) Different frequencies between electrical generating systems and other systems. EUROCAE ED-248 is an accepted means of compliance with [VTOL.2500](#_DxCrossRefBm1877490409)(b) concerning electromagnetic compatibility, except that the note in its Table 3, paragraph 6.2, for helicopters or small aircraft with HF radio transmitters installed does not apply to VTOL capable aircraft.