What was found
AIRCRAFT WAS TEST FLOWN AFTER ANNUAL INSPECTION. DURING FLIGHT AT AIRSPEED 10 KNOTS LESS THAN REDLINE, THE 6 LOWER COWL MOUNTS FAILED AT THE BONDED AREA TO THEIR BACKING PLATE. THE COWL CONTACTED THE SPINNER BULKHEAD WITH MINOR DAMAGE. STILL HAVE 2 NEW MOUNTS PURCHASED AT THE SAME TIME AS THE ONES THAT FAILED. THEY ARE STAMPED WITH THE PROPER NUMBERS AND CURE DATE, HOWEVER, THE LAST 2 DIGITS OF P/N ARE OF A LARGER SIZE NUMBER THAN THE REST OF THE P/N'S.