Advanced repairs increase service life and profitability

Engine Parts and Accessories Repair (EPAR)
PID tool with repair facts

The Engine Parts and Accessories Repair (EPAR) section of the Engine Services product division has an excellent pool of expertise. Customers can find a huge number of repairs for all the parts & accessories of an engine or APU in almost 180 special Product Information Documents (PID) – which offer enhanced performance and prolonged service life. 

Developing new methods and technologies

Lufthansa Technik has established itself as a well known independent provider for engine parts and accessories repair. To avoid scrapping of expensive parts during engine overhaul, the team of specialist engineers first of all asks themselves which parts of a given engine have been scrapped, how often and why. It is this approach which has led to ideas for developing new methods and technologies, driven by the comprehensive experience on the market need and thus tailored precisely to customers' requirements.
The result of many years of research and development is a comprehensive offer of repairs. These repairs are abstracted in the Product Information Documents (PID), in which the key facts relating on each repair are explained.
 

Some repair examples out of many

A few examples will illustrate the philosophy of the EPAR engineers. A Plasma Tip Repair is applied during the repair of high-pressure compressor blades on the CFM56 (stages 5 to 9). This special repair procedure developed by Lufthansa Technik as an alternative to welding processes offers the customer a number of benefits. First of all, elimination of heat treatment has the effect of prolonging the useful life of the blades, as for weld-repair parts an upper limit of four heat treatments is specified by the manufacturer. Moreover, the repair is less expensive because it may be performed on a whole set of blades rather than individual welds. And as the chord length is not compromised and not reduced by this EPAR Special Repair, the aerodynamic efficiency of the blade is retained.

The combustion chamber of the engine family V2500-A1/A5/D5 is another example for the Lufthansa Technik approach. Exposed to severe thermal stress, the combustion chamber fuel nozzle guide may exhibit cracking and severe oxidation over extended engine operation. If the thermal barrier coating bursts during this process, the nozzle guide may sustain damage which cannot be repaired. Again, to avoid scrapping – the OEM manual offers no repair here – Lufthansa Technik has developed a special repair method to restore the damaged nozzle guide. To increase the service life of the nozzle guide, future heat damage is prevented by proprietary enhancements such an extended thermal barrier coating. This repair has enabled the scrap rate to be slashed from 90 percent to 30 percent. As comparative tests have shown, the repaired parts deliver a longer service life than new parts.

As a third example, Lufthansa Technik has developed several repairs for damaged fuel manifold sections. By such section replacement repairs the original condition of the fuel manifold is fully reconstituted. The repair is applicable for almost all fuel manifolds with splits, cracks or kinks, etc. The repair procedure includes appropriate cleaning steps, a defined cut- off of the damaged area(s) followed by the insert of new tube section by specified welding processes. A comprehensive final quality control program is executed including visual and radiographic inspection, hydrostatic pressure test and fluorescent penetrant inspection (FPI) tests. Again customers may profit from these special repairs and Lufthansa Technik's long term repair experience to avoid unnecessary scrap by application of sophisticated repair technologies. 

What EPAR aims for

The examples cited above illustrate how EPAR aims not only to minimize the number of reasons why parts have to be scrapped but also to achieve the maximum cost-efficiency by prolonging the remaining service life of a given part beyond that of a new part – an additional efficiency gain. On top of this, in many cases the engineers succeed in improving the efficiency of the engine – an extra bonus. It goes without saying that the procedures offered have the necessary official Authorities certification. 

Where to find our information

The easiest way to access the PIDs is through the Lufthansa Technik homepage at www.lufthansa-technik.com/epar. Under ‘Special Repairs' a well organized and self-explanatory search tool enables the user to perform rapid searches by engine type, section, ATA-chapter or part number or to carry out a global search. One page summaries of the repairs offered can then be downloaded as a PDF file, which is supplemented by a query function.
On account of this combination of performance and cost-effectiveness, the EPAR product portfolio is constantly gaining popularity, a strong feedback for the Lufthansa Technik's engineers to explore new repair methods and technologies.