The problem in Plant X is failure of the boiler pipe. The failure of the pipe that occurred is known by the indication of leakage in the boiler unit 7 in the form of sound abnormality in the area of the economiser and with the leak in the area Soot Blower No. 7 - 11 Secondary Superheater (SSH out) area with make up water has reached 20-22 Ton./Jam. Field observations indicate deformation and rupture in the SSH Out pipeline. The purpose of this research is to know the main cause of boiler pipe failure and its failure mechanism, and to know the solution to overcome it so that similar failure does not happen again. The method of this research using Root Cause Failure Analysis (RCFA) method. The results of this reseacrh indicate that the leakage of the boiler pipe caused by the failure of the pipeline in the form of overheating. Overheating is known by the evidence in the form of pipe shapes such as fish mouth. On checking visually as well as checking using a boroscope on the inside surface of the pipe, indicates the presence of a fouling attached to the outer and inside surface of the boiler tube of SSH unit 7. In Scanning Electron Microscope (SEM) testing, there were also 619 um of oxidation process crust. In addition, an Electron Dispersive Spectroscopy (EDS) scan (spectrum 9) was performed, proving that the crust was the result of oxidation at high temperatures with a Fe content of 6.2 wt%. The presence of a crust attached to the pipes causes the transfer of heat from fire to water or steam in the superheater to be disturbed. No smooth heat transfer causes the pipe wall to be very high in temperature and the material softens so that the pipe rupture and leaks. The solution to pipe failure does not occur by cleansing the pipe on the superheater pipeline by operating the sootblower periodically, performing the excess water control according to the SOP, and performing the lab test.