As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN FLIGHT, CREW FELT SLIGHT TO MODERATE VIBRATION FROM NR 2 ENGINE. AFTER LANDING FURTHER INSPECTION FOUND APPROX ONE INCH OF ONE OF THE 3 LPT DISK BLADES MISSING. REASON FOR FAILURE AT THIS TIME UNDER INVESTIGATION BY MFG, SB 72-3689. (K)