EMC

What is an Upset?. A permanent impairment of system operation that requires manual reset. A momentary impairment of system operation not requiring manual reset. An impairment of system operation. E.g. change from digital to analog state. An impairment of system operation, either permanent or momentary, which may or not require manual reset.

High-intensity Radiated Fields (HIRF) Protection according to FAR 25.1317 is applicable to: Each electrical and electronic system that performs a function whose failure would reduce the capability of the airplane or the ability of the flight crew to respond to an adverse operating condition. Each electrical and electronic system that performs a function whose failure would prevent the continued safe flight and landing of the airplane. Each electrical and electronic system that performs a function whose failure would prevent completing with primary mission. Each mechanical system that performs a function whose failure would prevent the continued safe flight and landing of the airplane. Not applied to mechanical systems. Each mechanical system that performs a function whose failure is not related to the continued safe flight and landing of the airplane.

With respect HIRF Protection iaw FAR25.1317(a), each electrical and electronic system that performs a function whose failure would prevent the continued safe flight and landing of the airplane must be designed and installed so that: The system is not adversely affected during and after the time the airplane is exposed to HIRF Certification Environment. 🡪 The function not the system. The system automatically recovers normal operation of that function, in a timely manner, after the airplane is exposed to HIRF Environment. 🡪 HIRF Environment I & II and it is only I. It does not matter if electrical and electronic systems are adversely affected. The function is not adversely affected during and after the time the airplane is exposed to the HIRF environment I. The system automatically recovers normal operation of that function, in a timely manner, after the airplane is exposed to HIRF environment I, unless the system’s recovery conflicts with other operational or functional requirements of the system. The system is not adversely affected during and after the time the airplane is exposed to HIRF environment II.

Regarding E3CPP document, indicate which of the following(s) statement(s) is(are) true: E3CPP collects all the requirements on EM Hazards (EMH) of a particular program. E3CPP details how EMH activities are being managed during a particular program. E3CPP declares which are the EMH test facilities and EMH analytical tools that will be used during a particular program. E3CPP must be approved by the Airworthiness Authority. E3CPP details how to deal with development, GFE, CFE and COTS equipment during a particular program. E3CPP is referred to in the Certification Program Plan as the main Means of Compliance for protection against EMH.

Design Margin of Electromagnetic Protection is. The difference between the demonstrated level of upset and worst case environment. The difference between the targeted design level and worst case environment.

Protection against External Environment is achieved through this main complementary means, in the following order: Cable installation, airframe and equipment. Equipment and airframe. Airframe, internal installation, systems equipment and electronic components.

According to the signal sensitiveness of onboard aircraft systems, which statements are true: A coupling could lead to interference. The cross coupling between wiring inside a same route or between two routes is not important to be taken into account.

If you follow recommendations of FAA AC20.136B for certifying the protection of electric/electronic systems against the indirect effects of lightning you can use equipment qualification without specific aircraft-level test or analyses (mark the correct option(s)): For Level B and C systems. For Level X Control and Display Systems. For Level A Display System. For any system. Aircraft test or analysis is mandatory in any case.

Which are the most relevant EM coupling phenomena that, according to guidance material of RTCA and EUROCAE, an EMH Compliance Engineer must consider to control the EM effects of airborne Transmitter Portable Electronic Devices: CEI, CCT and NIRT. IRA, NIRA, IRU and IRC.

Definition of lightning zone 1B: Lightning zone 1B does not exist. Those areas where first return stroke is likely during lightning channel with high expectation of flash hang on. Those areas where first return stroke of reduced amplitude is likely during lightning channel with low expectation of flash hang on. Those areas where subsequent return stroke of reduced amplitude is likely to be swept with low expectation of flash hang on. Those areas where subsequent return stroke of reduced amplitude is likely to be swept with high expectation of flash hang on.

What is the preferred electrical bonding method taking into account risk of corrosion?. Either face to face bonding or bonding by fasteners, but avoiding bonding jumpers when possible. There is not a preferred method providing that electrical conductivity is ensured. Bonding by fasteners. Face to face bonding.

The massive use of composite materials (CFC) in new aircrafts: Represents an improvement of the electrical properties of the aircraft structure. Improves the protection that the aircraft structure provides to the systems installed inside. Increases the local damage resulting from a lightning strike with regards to an equivalent metallic structure. Increases the probability that the aircraft receives a lightning strike.

The purpose of a bronze mesh protection implemented in the external face of a composite (CFC) laminate is: Protect the laminate against corrosion problems and external environment. La malla metálica en los fuselajes de material compuesto sirve para aumentar la conductividad eléctrica del material y así disipar mejor la energía absorbida en el impacto de un rayo.

Which of the following statements is correct for conducted interference and for the connectors and cables used in electronic devices?. The optical fiber does not attenuate the conducted interference. The connectors do not make any influence on the conducted interference. The possibility to have conducted interference is higher at lower frequencies. Cable impedance grows with frequency. Capacitive and inductive coupling can occur.

Regarding EMC Equipment Testing, indicate which of the following statements is (are) true: Equipment software can have effect on test results. EMC test setup does not need representative installation and interconnection, only adequate interference test levels. Limits in MIL-STD-461 and RTCA-DO-160 represent test levels necessary to show the equipment capability to maintain the required performance of critical functions when exposed to the expected EM environment. Test levels do not depend on equipment location and criticality. Test levels depend on equipment location and criticality.

Which of these protections are applicable at equipment level?. Overbraiding. Shielded cages. EMI filters.

When an equipment is installed in a protected zone (e.g a closed avionics bay), and you specify the required protection levels regarding HIRF Conducted threat for its wiring, you have to ask for: Exposed zone levels. Protected zone levels. Semi protected zone levels. Any of the former levels (a, b, c). It depends on where the other equipment that interfaces with your equipment are located, ant therefor where the wiring that connect them is routed. It must be the same zone as requested for the equipment location regarding HIRF radiated fields.