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Dedicated Eddy Current Unit

Dedicated Eddy Current Unit Dedicated Eddy Current Unit Inspection of Aircraft Fastener Holes With the Fasteners 'In Situ' A dedicated eddy current instrument, introduced by Staveley NDT Tech­ nologies is used to find flaws in aircraft fastener holes with the fastener remaining and a broad band Hall Effect sensor, in place. which results in much faster checking of the bolthole integrity. It also probes A faster and more sensitive system coil at the centre of the probe face and more deeply for smaller flaws, compared than conventional eddy current testing the Hall sensor rotating at its perimeter. with traditional eddy current methods, and offering considerable savings in If no defects are present, the system aircraft down time and costs by extending and provides more information about produces a virtual straight line on the the time between scheduled inspections, flaws, more graphically. It can be used CRT display. A defect alters the pulsed on any aircraft. the instrument is believed to be the only magnetic field, indicated by a rise of the one of its type for this application. In operation a square wave pulse is display waveform. This 'trace' indicates applied to a coil atop the fastener, both amplitude and radial position of Capable of finding flaws from the the flaw, its approximate depth is inducing eddy currents into the test part. surface to approximately 12.5mm deep determined by establishing the elapsed in aluminium, the unit displays both the The resulting magnetic field is then time of the returning pulse signal. radial position and approximate depth detected by a Hall Effect sensor, which generates a signal that translates to a of the flaw on the crt. measurement value. The Eddy Current The EDDYSCAN Nortec 30 as it is Staveley NDT Technologies, 18, Coil and Hall Effect sensor are integrated known, uniquely employs two different Buckingham Avenue, Slough. Tel: into a rotating scanner probe, with the electrical theories, Pulsed Eddy Current 0753 76216. nology. In June 1990, Scientific Atlanta, San Sikorsky, Bell Helicopters and West- Diego Operations signed a $9 million Scientific land are all well established users of production contract to supply the US RADS-AT, and developed diagnostic Army with helicopter rotor track and software for their aircraft. This latest balance equipment. This order is the Atlanta contract establishes RADS-AT as the first of a multi-year production contract. world leader in rotor track and balance, Since October, 186 RADS-AT equip­ 'Rads-At' and vibration problem solving. ments have been shipped to the US Army in Saudi Arabia. Stewart Hughes, based in Southamp­ ton, UK, is a research and development- Supplied to orientated company specialising in 1200 RADS-AT's vibration analysis technolgy and mach­ 'Desert The contract, issued by the US Army inery health management for helicopters. Aviation Systems Command (AVS- It pioneered the development of advan­ COM) in St Louis, covers the supply ced rotor track and balance technology Storm' and support of more than 1200 RADS- in the UK in the early 80's and has seen AT (Rotor Analysis and Diagnostic the development through to a product the user all the rotorhead adjustments System — Advanced Technology) sys­ set to become the market leader for the needed to bring vibration within limits tems to automate the maintenance task 90's. after only one flight. The system was of adjusting helicopter rotors to reduce jointly developed with Steward Hughes vibration. Ltd (UK) and is manufactured by Stewart Hughes Ltd, School Lane, Chandlers Ford, Eastleigh, Hampshire RADS-AT is a fully automatic system Scientific Atlanta using Steward Hughes' which uses 'expert' diagnostics to tell unique automatic blade tracking tech­ S0 5 3YG. Tel: (0753) 270027. 8 AIRCRAFT ENGINEERING — March 1991 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Aircraft Engineering and Aerospace Technology Emerald Publishing

Dedicated Eddy Current Unit

Aircraft Engineering and Aerospace Technology , Volume 63 (3): 1 – Mar 1, 1991

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Publisher
Emerald Publishing
Copyright
Copyright © Emerald Group Publishing Limited
ISSN
0002-2667
DOI
10.1108/eb037066
Publisher site
See Article on Publisher Site

Abstract

Dedicated Eddy Current Unit Inspection of Aircraft Fastener Holes With the Fasteners 'In Situ' A dedicated eddy current instrument, introduced by Staveley NDT Tech­ nologies is used to find flaws in aircraft fastener holes with the fastener remaining and a broad band Hall Effect sensor, in place. which results in much faster checking of the bolthole integrity. It also probes A faster and more sensitive system coil at the centre of the probe face and more deeply for smaller flaws, compared than conventional eddy current testing the Hall sensor rotating at its perimeter. with traditional eddy current methods, and offering considerable savings in If no defects are present, the system aircraft down time and costs by extending and provides more information about produces a virtual straight line on the the time between scheduled inspections, flaws, more graphically. It can be used CRT display. A defect alters the pulsed on any aircraft. the instrument is believed to be the only magnetic field, indicated by a rise of the one of its type for this application. In operation a square wave pulse is display waveform. This 'trace' indicates applied to a coil atop the fastener, both amplitude and radial position of Capable of finding flaws from the the flaw, its approximate depth is inducing eddy currents into the test part. surface to approximately 12.5mm deep determined by establishing the elapsed in aluminium, the unit displays both the The resulting magnetic field is then time of the returning pulse signal. radial position and approximate depth detected by a Hall Effect sensor, which generates a signal that translates to a of the flaw on the crt. measurement value. The Eddy Current The EDDYSCAN Nortec 30 as it is Staveley NDT Technologies, 18, Coil and Hall Effect sensor are integrated known, uniquely employs two different Buckingham Avenue, Slough. Tel: into a rotating scanner probe, with the electrical theories, Pulsed Eddy Current 0753 76216. nology. In June 1990, Scientific Atlanta, San Sikorsky, Bell Helicopters and West- Diego Operations signed a $9 million Scientific land are all well established users of production contract to supply the US RADS-AT, and developed diagnostic Army with helicopter rotor track and software for their aircraft. This latest balance equipment. This order is the Atlanta contract establishes RADS-AT as the first of a multi-year production contract. world leader in rotor track and balance, Since October, 186 RADS-AT equip­ 'Rads-At' and vibration problem solving. ments have been shipped to the US Army in Saudi Arabia. Stewart Hughes, based in Southamp­ ton, UK, is a research and development- Supplied to orientated company specialising in 1200 RADS-AT's vibration analysis technolgy and mach­ 'Desert The contract, issued by the US Army inery health management for helicopters. Aviation Systems Command (AVS- It pioneered the development of advan­ COM) in St Louis, covers the supply ced rotor track and balance technology Storm' and support of more than 1200 RADS- in the UK in the early 80's and has seen AT (Rotor Analysis and Diagnostic the development through to a product the user all the rotorhead adjustments System — Advanced Technology) sys­ set to become the market leader for the needed to bring vibration within limits tems to automate the maintenance task 90's. after only one flight. The system was of adjusting helicopter rotors to reduce jointly developed with Steward Hughes vibration. Ltd (UK) and is manufactured by Stewart Hughes Ltd, School Lane, Chandlers Ford, Eastleigh, Hampshire RADS-AT is a fully automatic system Scientific Atlanta using Steward Hughes' which uses 'expert' diagnostics to tell unique automatic blade tracking tech­ S0 5 3YG. Tel: (0753) 270027. 8 AIRCRAFT ENGINEERING — March 1991

Journal

Aircraft Engineering and Aerospace TechnologyEmerald Publishing

Published: Mar 1, 1991

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