HIRF
The term HIRF is English High Intensity Radiated Fields , German about strong electromagnetic fields , which in the context of electromagnetic compatibility test for a civil aircraft is employed. In an HIRF test, test generators irradiate the electronic or electrical equipment to be tested with non-ionizing radiation in the frequency range from 10 kHz to 40 GHz at high field strengths and check whether this results in an undesired malfunction or failure. In this case, further measures to prevent interference, such as additional shielding or the installation of appropriate filters , must be taken for devices to be qualified .
motivation
Due to their exposed position during flight, aircraft such as aircraft are also exposed to electromagnetic interference fields with a comparatively high field strength in certain situations, such as in the vicinity of powerful radar systems . These electromagnetic fields can lead to undesired malfunctions or failures in the flight control in aircraft increasingly equipped with electronic devices and components, which in extreme cases can lead to an uncontrolled crash. For example, the short-term pulse power of a ground-based pulse radar can be over 100 MW and generate interference signals on electrical cables inside an aircraft.
The limit values for the field strengths to be tolerated as part of the HIRF test are frequency-dependent and, depending on the qualification level, are set out in several tables in the relevant guidelines. The total of three different qualification levels set different high limit values depending on the expected damage and number of victims in the event of a failure of a flight-critical system triggered by an HIRF: The highest limit values apply to particularly critical electronic components, the failure of which can lead to an uncontrolled crash with a peak value for the component of the electric field strength of just over 7 kV / m.
The HIRF area is thematically linked to the area of lightning protection for aircraft, although the source of interference has a natural origin. To distinguish, the borrowed designation HIRF / L ( English HIRF and Lightning ) is sometimes used in the literature for lightning protection on aircraft .
literature
- David Wyat: Aircraft Electrical and Electronic Systems: Principles, Maintenance and Operation . Routledge, 2008, ISBN 978-0-7506-8695-2 , Chapter 19.4.3 .: Certification of aircraft for HIRF and lightning protection .
- SAE International (Ed.): ARP5583A: Guide to Certification of Aircraft in a High-Intensity Radiated Field (HIRF) Environment . 2010 ( online ).
Individual evidence
- ↑ a b U.S. Department of Transportation Federal Aviation Administration, FAA (Ed.): AC20-158A, The Certification of Aircraft Electrical and Electronic Systems for Operation in the High-Intensity Radiated Fields (HIRF) Environment . 2014 ( Online [PDF]).
- ↑ European Organization for Civil Aviation Electronics (Ed.): EUROCAE ED 107: Guide to Certification of Aircraft in a High-Intensity Radiated Field (HIRF) Environment . 2010 ( online ).