A B737-300 WING INSPECTION WAS NOT ACCOMPLISHED DUE TO INTERP OF THE ENGINEERING ORDER STATING INSPECTION AT NEXT 'C' CHK OR 4000 CYCLES.

Narrative

ACFT X WAS REPAIRED AT THE ZZZ1 MAINT FACILITY PER ENGINEERING ORDER NO XXXXX. THE DATE OF THE ENGINEERING ORDER WAS MAR/XA/01. AT THE TIME THE ACFT TOTAL WAS 47122 HRS AND TOTAL CYCLES OF 33516. THE ENGINEERING AUTH CALLED FOR A REPETITIVE INSPECTION AT NEXT 'C' CHK OR 4000 CYCLES; WHICHEVER COMES FIRST. THE SUBSTANTIATION FOR THE ENGINEERING ORDER CAME FROM BOEING TELEX. WHEN THE ACFT CAME TO ZZZ ON OR AROUND MAY/MON/02 FOR ITS FIRST 'CX' CHK AFTER THE FIND THE ACFT HAD FLOWN 1807 CYCLES. MY INTERP OF THE TERM 'C' CHK; AS USED IN THE BOEING TELEX; MEANS FULL 'C' AS DESCRIBED IN B737 SRM 51-10-02 PAGES 11 AND 12. ACR X USES A 'CX' CHK; WHICH IS MADE UP OF A CX-1 AND A CX-2. (SEE ATTACHED ACR X 'ACFT MAINT PROGRAMS' DATED MAY/THU/02.) THE CX-1 THROUGH CX-6 IS SCHEDULED EACH 365 DAYS; OR THE ACCUMULATION OF 2530 HRS; WHICHEVER COMES FIRST. THE REF 'ACFT MAINT PROGRAMS' DOCUMENT SHOWS 'FULL 'C'' AT 5060 HRS. USING SRM 51-10-02 PAGES 11 AND 12; IT WAS DETERMINED THAT THE ACFT COULD CONTINUE OP UNTIL THE NEXT 'CX' OR ACCUMULATION OF 4000 CYCLES; WHICHEVER CAME FIRST; BEFORE THE REPEAT INSPECTION WOULD BE DUE. A DEFERRAL WAS ACCOMPLISHED USING ACR X DEFERRAL PROCS FOR BASE MAINT AS DESCRIBED IN ACR X 330-10. THAT ACFT CONTINUED OP UNTIL APPROX AUG/THU/02; WHEN AT THAT TIME THE ACR X PLANNING DEPT FOUND THE ITEM AND THOUGHT IT HAD BEEN MISSED DURING THE 'CX' CHK ACCOMPLISHED MAY/MON/02. ENGINEERING BECAME INVOLVED AND BECAUSE THEY ALSO BELIEVE THE ITEM HAD BEEN MISSED THEY OBTAINED ANOTHER BOEING TELEX WHICH AUTHORIZED THE FIRST OR 'INITIAL' REPEAT INSPECTION TO BE ACCOMPLISHED PRIOR TO THE ACCUMULATION FO 4000 CYCLES; FROM THE FIND; AND DROPPED THE 'C' CHK REQUIREMENT. AS OF THIS DATE; THE ACFT HAS ACCUMULATED A TOTAL OF 2787 CYCLES FROM FIND AND IS SCHEDULED FOR 'CX' IN FEB/03. IRONICALLY;; THAT IS MOST LIKELY WHEN THE RECHK WILL BE ACCOMPLISHED. THIS CHANGE TO THE ORIGINAL ENGINEERING AUTH CAME ABOUT DUE TO A DIFFERENCE OF INTERP OF THE TERM 'C' CHK AND 'WHEN IS A 'C' CHK ITEM DUE?'