What was found
DURING BASIC CHECK, INSPECTION DISCOVERED CORROSION ON THE AFT CABIN RT AFT BEAM AND ALSO ON A PREVIOUS REPAIR DOUBLER ON THE SUBJECT FLOOR BEAM. COMPASS REQUESTED AND RECEIVED RELIEF IN THE FORM OF ETD2015-170-034677A WHICH PROVIDES A PERMANENT REPAIR BY INSTALLING A REPAIR DOUBLER AND REPLACING THE PREVIOUSLY INSTALLED REPAIR DOUBLER. THE CORROSION DAMAGE (NEW BEAM DAMAGE) APPROXIMATE DIMENSIONS ARE 2.41 INCHES X .97 INCH TO DEPTH GREATER THAT 50% ORIGINAL MATERIAL LOSS IN MULTIPLE AREAS (REF FIGURES 1 AND 2). THE PREVIOUS REPAIR DOUBLER CORROSION DAMAGE APPROXIMATE DIMENSIONS ARE 2.0 INCHES X 6.0 INCHES TO DEPTH GREATER THAT 50% ORIGINAL MATERIAL LOSS IN MULTIPLE AREAS (REF FIGURE 1). COMPASS ENGINEERING HAS CLASSIFIED THIS REPAIR AS A MAJOR REPAIR. EO E175-53MR-175.1 WILL BE ISSUED TO ACCOMPLISH FOLLOW UP INSPECTIONS. INSPECTION INSTRUCTIONS: TASK 53-23-005-0001 (INTERNAL GVI THRESHOLD OF 20,483FC OR 27,242FH, INTERVAL OF 10,133FC OR 13,476FH PER ETD2015-170-034677A ANAC DER FORM ATTACHED) IS SUFFICIENT AND IS MET USING THE INSPECTION REQUIREMENTS: MPG/MRBR REVISION NR 10. THRESHOLD IS COUNTED SINCE NEW. ACCOMPLISHMENT OF THIS MAJOR WAS ON EO E175-53MR-175.