FUTURE TRENDS IN AEROSPACE EMC - Programme
TRW Conekt, Solihull, West Midlands
14th June 2006
As part of Conekt's centre of excellence for validation in the aerospace industry, it has announced a series of one-day seminars to be hosted at it head office in Solihull, West Midlands. The first seminar will focus upon 'future trends in aerospace electro-magnetic compatibility (EMC)' and is aimed at improving knowledge transfer across the aerospace industry.
Confirmed abstracts from the conference programme include:
The Need for "Good" Measurement from EMC Testing
By Dr Christopher C R Jones (BAE Systems, Warton, UK)
The emphasis in EMC testing is too often on testing and not sufficiently on measurement. This would be understandable for pass/fail, go/no-go testing, but for qualification testing where the measured data is used as part of the equation in a safe use clearance, the quality of the measurement and presentation of the data is all-important. In this paper, the author will present the kind of process that has to be applied to the latest electromagnetic hazards clearances, driven by the growing reliance on complex, inter-dependant electrical and electronic systems for safety, specifically in the aircraft industry for safe continued flight and landing. Examples will be drawn from the clearances for lightning, electrostatic discharge and EMP threats. It is intended that test houses and equipment suppliers will become more aware of the significance and need for rigour and quality in measurement of test and response parameters, and hoped that understanding precedes effect.
Aerospace EMC Qualification - Implementation of Recent Changes
By Dr Luke Turnbull (EMC Technical Manager, TRW Conekt)
EMC requirements for Aerospace testing are continually evolving. The largest changes in recent years are a step-change increase in the field strengths for radiated immunity testing and the requirement for lightning tests to be performed as multiple stroke and multiple burst waveforms.
The step-change of levels from typically 200 V/m to typically 3000V/m for radiated immunity (a nominal one-hundred-fold increase RF power requirement) has led to this test becoming known as High Intensity Radiated Field (HIRF). We will describe the work that our laboratory has performed to achieve this extreme capability as a frequency swept test using free-field methods.
We will also describe the work that we have done to attain capability for lightning testing at all levels of DO-160 Section 22, multiple-stroke and multiple-burst, also covering most other aircraft lightning specifications.
Programme timescales are also constantly being reduced in all aspects of engineering, and this pressure is being felt within the aerospace industry. We have been working with our customers on concepts to reduce time and cost of setting up the product for testing, which for a complex system can take weeks before testing can start. We will also be able to remove the system from a chamber for a pause in testing, and be able to reproduce a setup very accurately to improve testing reproduceability. We will discuss these concepts and the associated facilities.
Developments in the field of avionics testing Equipment relating to Indirect lightning events
By Nicholas Wright (Sales Manager, EMC Partner)
Aircraft design and assembly is a global phenomena. Today, systems can be designed, manufactured or tested in any country, only being shipped for final integration in the assembly plant.
This global process relies on a standardised set of test procedures being in place.
The process starts with equipment manufacturers who, logically, want their equipment to be fitted in as many different aircraft types as possible. There is, however, one small fly in the ointment. Aircraft manufacturers do not make identical aeroplanes. Each aircraft type is unique, with a specific set of test requrements that only the final system integrator can define. So where does this leave the poor old equipment manufacturer who wants to remain neutral and thus have the highest chance of commercial success. Enter DO160 to the rescue.
DO160, currently at issue E, is the answer to equipment manufacturers dreams. It provides a set of generic tests that provide an indication to system integrators of suitability for the task in hand. But that is all.
Competition is driving new developments in the design of aircraft, not least the desire to seek that competitive edge. To fly further, carry more passengers, be more fuel efficient or ideally a combination thereof.
The mammoth A380 will be the largest commercial jet when it enters service. But to achieve performance targets higher amounts of composite material than in any previous Airbus have been employed. Up to 26%. This will enable the A380 to deliver more passengers over a long distance. The world masters in composites for commercial aircraft are however, Boeing. The 787 will include a phenomenal 60% composites and will be the first fully electrical aircraft, no more hydraulics, no more bleed air.
Just taking these two examples, it is easy to see that lightning events will interact differently with the airframe and the electronics will experience unique interference. Both these aircraft have their own specifications, based on DO160, but taking into account the materials and equipment.
Airbus have written the ABD0100.1.2 and Boeing the D6-16050-5.
The single most significant deviation from DO160 is the need for waveform 5A to be induced into cable harnesses as a voltage waveform instead of the current waveform used for ground injection in DO160.
Airbus have also introduced specialist voltage waveform tests, but with waveform 4.
The pace of change is not slacking as competition increases on all fronts. Airbus have already announced the A350 as a competitor to the Boeing 787, and one thing is sure, the test requirements will continue to evolve.
A fourth paper will be given by Richard Baker of Goodrich Corporation.
The seminar is free of charge. If you would like to receive further information, please contact Jane Preece on Jane.Preece@trw.com.
