What was found
THE RIGHT WING REAR SPAR IS CRACKED AT THE BUTT END OF THE SPAR INTO THE SPAR/FUSELAGE FITTING FASTENER ATTACH HOLES. CRACKS ARE AS ILLUSTRATED IN SERVICE LETTER 406, REV A. THE REAR SPAR WAS REPLACED WITH A RAINBOW FLYING SERVICE SPAR, PN RFS5-26. A FORM 337 HAS BEEN FILED WITH THE ACFT OWNER AND FAA TO DETAIL THE REPAIR AND WING COVERING. THE SPAR HAD NO INDICATION OF ANY DAMAGE THAT WOULD ACCOUNT FOR THE CRACKS. THE BUTT END OF THE SPAR HAD VERY LITTLE VARNISH WHICH MAY NOT HAVE PROTECTED THE END OF THE SPAR FROM WEATHERING.