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least as good as a riveted joints.
FSW reduces the weight of the plane by at least 50 lbs; this weight reduction comes not from the
loss of rivets, but from the stronger structures obtained by using FSW. Unlike laser or fusion
welding, FSW enables the use of high strength 7XXX aluminum alloys to supplement the 2XXX
series used throughout the plane. The stronger alloys permit thinner, lighter wall sections and
reduced flange widths.
In addition to enabling stronger alloys, FSW shortens process cycle time, and decreases costs.
Work time was reduced by 40% from traditional riveting. While manual riveting operations have
speeds below 2 inches/min, and automated riveting tops at 6 inches/min, FSW enables speeds
greater than 20 inches/min, up to around 40 inches/mm in the laboratory, The fast, highly
automated FSW saves between $50,000 and $100,000 per plane, requires less space on the factory
floor, and its easier to cleanup.
Airbus A380
In 1997, BAE developed a small-scale FSW research program. The positive results encouraged the
acquisition of a FSW machine. This process is being studied by BAE Systems for possible
application to the manufacture of components for the Airbus A380.
Space Shuttle
The state of the art for welding the new super lightweight external tank two years ago was VPPA;
today, that technology is slated for replacement by FSW. The viability of the technology was
demonstrated when NASA’s Marshall Center used a retractable pin tool to weld a full-scale
External Tank hydrogen barrel.
The External Tank project will implement FSW on the longitudinal barrel welds on both the liquid
oxygen and hydrogen tanks. External Tank 134—scheduled to fly in January 2005—will be the
first tank to incorporate the process.
Delta IV
Two years ago, we expected VPPA to gain share in aeronautical applications; however, with the
introduction of the retractable pin FSW, VPPA is likely to be used less instead of more. Propellant
tank segments for the Delta IV are joined into a barrel using the FSW, and the finished barrel
sections are joined using VPPA. Barrel segments range up to 40 feet in length with multiple barrels
joined to form the largest tank at more than 77 feet in length. The ends of these tanks consist of
domes joined to the barrels using VPPA. It is likely that the retractable pin FSW will eventually
replace the VPPA welds.
Conclusions
FSW has made spectacular advances in the last two years, enabling joining the main components of
a commercial jet, parts of rockets, and displacing VPPA for the welding of the external tank of the
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Space Shuttle. FSW can now join complex curved surfaces, sections of variable thickness, and
circular sections without leaving a keyhole. This is possible because of the recent introduction of a
revolutionary tool with a retractable pin. FSW is likely to continue increasing its share of welding
in the aeronautic industry. It is likely that it will completely replace VPPA in the welding of
rockets, and possibly laser welding in airplanes. Arc welding processes will continue to decrease in
relevance for the aeronautic/aerospace industry. Even specially-tailored processes such as VPPA
will lose ground to FSW for aluminum alloys.
References
1. Mendez, P.F. New Trends in Welding in the Aeronautic Industry. in New Trends for the
Manufacturing in the Aeronautic Industry. 2000. San Sebastián, Spain.
2. Eagar, T.W., Energy Sources Used for Fusion Welding, in ASM Handbook. 1993, ASM
International. p. 3-6.
3. Robinson, I.B. Aluminum and Its Alloys: Weldability. in Welding Technology for the
Aerospace Industry. 1980. Las Vegas, NV: American Welding Society.
4. Berggreen, J. Economical Manufacturing and Inspection of the Electron-Beam-Welded
"Tornado Wing Box". in Advanced Joining of Aerospace Metallic Materials. 1985.
Oberammergau, Germany: Advisory Group for Aerospace Research & Development
(NATO).
5. Shaw, C.B. Welding Research for Aerospace in USA. in International Congress on Welding
Research. 1984. Boston, MA.
6. Eclipse Aviation. www.eclipseaviation.com
7. American Welding Society and Edison Welding Institute, Welding-Related Expenditures,
Investments, and Productivity Measurement in U.S. Manufacturing, Construction, and
Mining Industries. 2002.
8. Schubert, E., M. Klassen, and G. Sepold, High Power Laser Applications for the Transport
Industry. Welding in the World, 1999. 43(Supplementary Issue): p. 154-162.
9. The Welding Institute. http://www.twi.co.uk
10. NASA Marshall Space Flight Center. www.msfc.nasa.gov
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EASA AIRWORTHINESS DIRECTIVE
AD No.: 2006 - 0174
Date: 21 June 2006
No person may operate an aircraft to which an Airworthiness Directive applies, except in accordance with the
　
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