What was found
THE CRACK EMANATES FROM THE 5TH RIVET OUTBOARD OF THE LOWER FORWARD WING BOLT FITTING, 4TH RIVET FROM END OF SPAR CAP, IN THE FRONT ROW OF RIVETS, AND EXTENDS TO THE LEADING EDGE OF CAP. THE A/C PASSED 2-400 HOUR WING SIRM INSPECTIONS. 181 HRS INTO NEXT INTERVAL WAS WHEN CRACK WAS DETECTED DURING ROUTINE MAINTENANCE. BEECH HAS REDUCED INTERVAL FOR EDDY CURRENT INSP OF SPAR CAP TO 200 HRS DUE TO RECURRENCE OF THIS PROBLEM REF 8110-4 FOR N692M FOR SIMILAR DETAILS. A/C IS ON USFS CONTRACT.