What was its description?
SELECT T1.fault_log_entry_id ,  T1.fault_description FROM Fault_Log AS T1 JOIN Fault_Log_Parts AS T2 ON T1.fault_log_entry_id   =   T2.fault_log_entry_id GROUP BY T1.fault_log_entry_id ORDER BY count ( * )  DESC LIMIT 1
its description refers to the description of the fault with the most associated parts;