The first FAA Supplemental Type Certificate (STC) for Low Plasticity Burnishing (LPB) has been granted to Delta Air Lines’ maintenance division, Delta TechOps, to mitigate fretting induced fatigue cracking in the high pressure compressor section of the CFM56-7. The initial STC, SE03036CH, allows the use of LPB on the first stage blade. LPB was shown to increase the fatigue life of a damaged surface to more than ten times that of the undamaged baseline. The STC is the culmination of the collaboration between Delta TechOps and Lambda Technologies, the company that created LPB.
Significant performance and life improvements have been documented with the use of LPB in other applications. Thousands of engine and structural components have been treated with LPB in military applications. SBIR contracts with NAVAIR have led to full production to reduce processing costs for the P-3 Orion propeller bore, and to mitigate FOD in the F402 engine used in the AV-8B Harrier. With issuance of the STC, Delta TechOps can begin providing benefits to the commercial fleet’s most popular engine.