Aircraft Maintenance Technology

APR 2014

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Page 26 of 35 | 27 to inconsistent material removal rate and a higher chance of goug- ing the part. W henever part of the sander lifts off the surface, the vacuum seal (if the sander is connected to a vacuum) fails, spewing dust everywhere. Many aircraft paints and primers contain lead, cadmium, or hexavalent chromium, exposure to which is dangerous to people and the environment and regulated by OSHA, subjecting noncompliant shops to fines which can be significant. The ergonomic stress associated with manual sanding causes fatigue, which impacts process time, finish con- sistency, and schedule predictability. It is important to note that these many challenges are not the fault of the personnel assigned to sanding — they're diligent and know exactly how a surface needs to look to be ready to take paint. Nor are they the fault of the sanding tools they are using, which are efficient and long-lasting. The real problem that needs fixing is that a human being has to hold the tool, orient it f lat on the surface being sanded regardless of orienta- tion, and apply pressure. Ergonomically, humans simply aren't built to do those things very well. Solution: What would it look like? A successful technology which can, and should, displace tradi- tional aerospace maintenance sanding will prevent exposure to vibration and dust, will help the operator sand faster and more consistently, and allow them to stand or sit comfortably while allowing their experience to guide and control the sanding rate — yielding the best possible finish in the least amount of time. By boosting productivity, such a technology will make each worker more valuable to the enterprise, and will also save on insurance costs, absenteeism, retraining costs, and cost of rework, repair, and scrap (COR RS). By making the sanding process faster and less expensive, such a technology can make it affordable to take off more of the old paint than current manual sanding operations, which could reduce weight by hundreds of pounds, and thus have a significant effect on fuel consumption. A major airline would save more than $5 mil- lion each year, and reduce CO2 emissions by 28,000 tons, if each plane in its f leet was 200 pounds lighter. This calculation is based on fuel consumption; a reduction of 80 kg saves 4,400 gallons of fuel per year. 200 pounds is 91 kg, and thus would save 4,990 gallons/year on each of a typical large airline f leet's 500 planes (figures on f leet size of the top 10 U.S. airlines range from 1,189 (United) to 225 (UPS), and the top 10 average is 557 aircraft) — for a f leet-wide savings of $7,209,859 at today's jet fuel price of $2.89. Thus, the $5 million seems conservative as this would apply to a f leet of 347 aircraft. One possible solution is the EMM A (Easily Manipulated Mechanical A rm) ergonomic sanding system from Temple A llen Industries in Rockville, MD. EMM A is an entirely pneu- matic arm that wields sanders or other tools at the direction of an operator via a joystick interface. An auto-adjust feature allows EMM A's operator to dial in the appropriate sanding pressure for each operation, and the joystick allows the sander at the end of the arm to sweep back and forth at whatever speed generates the best resulting surface. The free-rotating wrist on the end of the EM M A arm guarantees that the sander at the end is always f lat on the surface being sanded, and thus the vacuum seal is maintained, abrasives last longer, and fewer paper changes are required. Productivity improvements drive some customers, while for others, ergonomic improvements and improved dust capture are the primary motivations for updating their processes. The EMM A Belly System solves the greatest ergonomic challenge in surface preparation — sanding overhead. EMM A allows the operator to comfortably sand the belly of an aircraft, underneath a wing, or any other overhead horizontal surface. The operator sits in the adjustable reclining chair and controls the system via the joystick box. Deployed widely throughout aerospace manufacturing operations, there are EMM A systems installed at Boeing, A irbus, Embraer, Triumph, and Spirit, among others. Units are also used for commercial and military de-paint opera- tions at British Airways (all aircraft), Robins A FB (C-17s), and the U.S. Nav y (T-45s). The military customers in particular value the technolog y's ability to prevent worker exposure to hexavalent chromium and vibration, to address the chal- lenges of chemical agent resistant coating (CA RC) paint, and to reduce f lowdays. It also reduces process variance and the risk of damaging composite substrates. There is a great deal of sanding required by aircraft main- tenance operations, and it presents ergonomic, safety, and schedule issues which raise costs and threaten worker health. Using such a solution could capture some of the extra value the improved sanding productivity allows by getting planes back to their owners sooner, having taken off a few hundred pounds more of the old paint than they could have done oth- erwise. Airlines win, MRO contractors win, workers win, and the environment wins. For more information visit With the ability to position the technician in a more comfortable position, sanding operations with EMMA reduce worker fatigue and injury from repetitive stress injuries. TEMPLE ALLEN AMT_26-27_MilitarySanding.indd 27 4/3/14 1:57 PM

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