What was found
DURING HEAVY MAINTENANCE: TAIL CONE SKIN BETWEEN FR83-84 & ABOVE S15L CORRODED, PERMANENT REPAIR; REFERENCES: /1/ A321 SRM TASK 53-51-11-50-A ITEM 5 /2/ A321 SRM TASK 53-51-11-283-006 /3/ SRM TASK 53-51-11-300-002. /5/ AIRBUS DOSSIER 81714282 /6/ ECA 331 /7/ MX/MCC EMAILS /8/ HOLE PITCH TEMPLATE /9/ TO ANNOTATE (ADDITIONAL DIMENSIONS). DESCRITIPTION: ON 12/22/2025, AIRCRAFT N903JB (MSN 05783) BOS WAS FOUND WITH CORROSION DAMAGE ON THE TAIL CONE SKIN BETWEEN FR83-84 & STGR 15L. SEE REF /4/ DAMAGE PICTURES FOR DETAILS. PER REF /1/ SRM FIGURE, THE SKIN PANEL IS 0.055” THICK AND MADE OF ABS5043A018/3.1364T42. AFTER BOS MX CLEANED THE AREA AND PERFORMED FURTHER INSPECTION, THE CORROSION DAMAGE IS CONFIRMED TO BE AFFECTING AN AREA OF 8.000” L X 1.6875” X W, THE EXTERNAL SKIN AND NO OTHER DAMAGE FOUND ON ANY OTHER STRUCTURAL COMPONENTS. THE REF /2/ SRM ADL WAS REVIEWED AND FOUND TO BE OUT OF LIMITS. THE REF /3/ SRM REPAIR WAS ALSO REVIEWED AND FOUND TO BE NOT APPLICABLE DUE TO THE REPAIR BEING AT THE EDGE OF THE SKIN PANEL. AIRBUS WAS CONTACTED VIA REF /5/ DOSSIER ALONG WITH A REPAIR PROPOSAL TO PERFORM A CUT OUT & INSTALL A REPAIR DOUBLER FOLLOWING REPAIR PRINCIPLE OF REF /3/ SRM REPAIR (SEE REF 4 PDF FOR DETAILS) AND AIRBUS APPROVED THE PROPOSED REPAIR SCHEME PER REF /5/ DOSSIER MSG /007. BOS MX CONFIRMED THEY CANNOT PERFORM THE FREEZE PLUG REPAIR ON HOLE #47 AS AIRBUS STATED IN REF /5/ MESSAGE /034. MCC DECIDED TO REPOSITION THE AIRCRAFT VIA MX-FERRY UNDER REF /7/ AFTER INSTALLING REPAIR PARTS (FILLER AND DOUBLER) PER A321 SRM 53-51-11-300-002 WITH THESE DEVIATIONS: 1. INSTALL FASTENERS PN CR3222-X-XX A.DO NOT INSTALL ANY FASTENER IN HOLE #47 2. OMIT SURFACE PROTECTION APPLICATIONS 3. APPLY SPEED TAPE OVER THE REPAIR AREA PER A321 SRM 51-77-12-911-001 .PER AIRBUS REF /5/ MESSAGE /054, IF THE PITCH BETWEEN HOLE 56-57 IS NO LARGER THAN 6D SPACING (0.954 INCHES), THEN THE CURRENT FASTENER LAYOUT IS ACCEPTABLE WITH THE FOLLOWING PROVISIONS AS: 1. FASTENER HOLES ARE WITHIN TABLE 3 (SOLID RIVETS) AND TABLE 4(BLIND RIVET) OF A321 SRM 51-44-11 GUIDELINES. 2. THE FREEZE PLUG REPAIR ON HOLE #47 IS COMPLETED AS PER REF/5/ MSG 042 GUIDELINES. 3. REPAIR CAN BE COMPLETED PER A321 SRM 53-51-11-300-002 WITH THE DEVIATION OF THE CUT OUT BEING AT THE EDGE OF THE SKIN AND THE FASTENER LAYOUT AS PRESENTED. NOTE THAT DOUBLER MATERIAL CLAD2024T3 WITH THICKNESS OF 0.063 INCH WAS CONSIDERED AS ACCEPTABLE IN REF/5/ MSG /019, IN CASE 0.56 GAGE WAS NOT AVAILABLE, AS PER REF/3/ SRM INSTRUCTIONS. EC A25-1179-01 ISSUED INSTALLING THE REPAIR PARTS WITH CR3223-*-** AT BOS TO GET THE AC READY FOR REPOSITION. EC A25-1179-02 IS ISSUED TO REMOVE THE TEMPORARY REPAIR (EC A25-1179-01), PERFORM BUSHING REPAIR ON HOLE #47 PER 51-73-12, AND COMPLETE ADDITIONAL AIRBUS-PROVIDED WORK VIA REF /5/. SUBSTANTIATION:THIS REPAIR IS ON THE TAIL CONE SKIN WHICH IS PRIMARY STRUCTURE & PSE PER SRM 51-11-12 TABLE 17 AND IS CLASSIFIED AS MAJOR. THIS EC IS APPROVED AS PER AIRBUS INSTRUCTIONS IN REF/5/ MSG /048 AND /054. AIRCRAFT IS NOT TO RTS UNTIL WE RECEIVE FINAL RDAF HARD COPY FROM AIRBUS.*** REV 01*** /10/ AIRBUS RDAF 81714282-004-2025 A /11/ EA 160-2025-012 REV IR DESCRIPTION: ON 12/31/2025 AIRBUS PROVIDED REF/10/ RDAF APPROVING THE PERMANENT REPAIR INSTRUCTIONS AS PER REF TD/81714282/081/2025#A COMPLETED BY STS ENGINEERING IN MLB WITHOUT DEVIATION. PERMANENT REPAIR INSTRUCTIONS INCLUDED EXTENSION OF THE CUTOUT TO REMOVE THE DAMAGED HOLE AS SHOWN IN DAMAGE REPORT AND A321 SRM 51-27-11. PERFORM HFEC OF THE SKIN TRIMMED EDGE AND SURROUNDING SURFACE PER SA NTM 51-10-08 TO CONFIRM NIL CRACKING. DVI PER SA NTM 51-90-00 TO CONFIRM NIL ADDITIONAL DAMAGES THAT NEED TO BE CONSIDERED. ENSURE EDGE MARGIN AND PITCH REQUIREMENTS PER A321 SRM 51-47-00 ARE MET, AND INSTALL OF EXTERNAL DOUBLER REPAIR AS PREVIOUSLY INSTRUCTED CONSIDERING THE LARGER CUT OUT. THIS REVISION OF EC A25-1179-01 IS ISSUED TO ACCOMPLISH PERMANENT REPAIR INSTRUCTIONS OF REFERENCE DAMAGE AS PER REF/10/ RDAF AND REF/11 STS EA. SUBSTANTIATION: THIS PERMANENT REPAIR IS APPROVED PER REF /10/ RDAF AND IS CLASSIFIED AS MAJOR. (E/C: A25-1179-02)