What was found
FLEXJET USA HAS REQUESTED, AMONG OTHER WORKS, . AD REQUIRES REPETITIVE INSPECTIONS ON ENGINES LPC ROTOR FAN DISK, DUE TO POTENTIAL CRACKS. DURING REVIEW OF THE FAA AD 2022-24-06, THE AD WAS FOUND NOT APPLICABLE, BY ENGINE S/N, TO THE ENGINES FITTED TO A/C N94FX (ENG#1 SN 12591 & ENG#2 S/N 12592). A FURTHER INVESTIGATION THEN REVEALED THAT, AS OF JAN 2022, ON BOTH ENGINES THE ORIGINAL LPC ROTOR FAN DISK P/N FW33927 (POST SB 72-101474 AND NOT AFFECTED BY AD) WERE REPLACED BY LPC ROTOR FAN DISK P/N BRR20791 S/N CTDK6092 (ENG1) & CTDK8144 (ENG2), PRE-SB 72-101474, TO WHOM THE INSPECTION REQUIREMENTS PROVIDED BY FAA AD 2022-24-06 ARE APPLICABLE. THIS CONFIGURATION IS NOT APPROVED SINCE, ACCORDING TO SB 72-101474, LPC ROTOR FAN DISK P/N FW33927, AS THOSE ORIGINALLY INSTALLED ON ESN 12591 & 12592, CANNOT BE REPLACED BY PRE-SB P/NS SUCH AS P/N BRR20791