What was found
WHILE AC WAS IN FOR HVY CK CORROSION FOUND ON CENTER FUSELAGE 2 LH LATERAL SEAT TRACK BTWN FR43 AND 59 ON UPPER CROWN. REPLACED SEAT TRACK PN 170-02056-007 IAW SRM 51-21-01, 51-41-01, 51-43-03, 51-43-04. SEE AAR NRC# 4500917-1000-0040 FOR DETAILS OF WORK PERFORMED. AC RTS'ED.