What was found
ALTERNATOR TO STARTER STRUT CRACKED. SUSPECT DUE TO ENGINE VIBRATION. SUBMITTER NOTICED THIS ON 4 OTHER AIRCRAFT ON MORE THAN ONE OCCASION. ALSO, ELONGATED BOLT HOLES THROUGH ALTERNATOR BRACKETS ON THE SAME (PA28-161) TYPE AIRCRAFT. THESE ELONGATED HOLES CANNOT BE DETECTED WITHOUT REMOVING THE BRACKETS AND ALTERNATOR FROM AIRCRAFT. SUBMITTER RECOMMENDS INSPECTING BY REMOVAL EVERY 100 HOURS.