What was found
ON MAY 24TH 2019 A SECOND STAGE POWER TURBINE BLADE FAILED PN 3044183-01. WHEN THE BLADE PORTION LEFT THE 2ND STAGE POWER TURBINE DISK PN 3037313 IT DESTROYED THE NEXT 5 BLADES IN ROTATION OF THE BLADED DISK. THE SUBSEQUENT OUT OF BALANCE CONDITION DESTROYED THE POWER SECTION IN APPROX 9 SECONDS. IT APPEARS THAT THE BLADE HAD BEEN CRACKED FOR SOME UNKNOWN AMOUNT OF TIME AND FINALLY WHEN THE CRACK REACHED 30% OF THE FIR TREE THE BLADE PORTION LEFT THE DISK. THE ENGINE HAD BEEN TO COVINGTON AIRCRAFT WO #220319 FOR A POWER SECTION LIGHT OVERHAUL (IRAN) 11/2015, 5436 TOTAL TIME WHERE THE DISK WAS DE-BLADED, NONDESTRUCTIVE TESTED AND RE-BLADED WITH 5 OF THE 43 BLADES REPLACED. WITH THE HELP OF THE MECHANIC THAT PERFORMS THE MAINTENANCE ON MY AIRPLANES WE HAVE FOUND 5 OTHER BLADES WITH CRACKS IN THE SAME AREA OF THE FIR TREE ON THIS DISK. WITHOUT DISASSEMBLY IT IS UNCERTAIN IF THE CRACKS ARE A RESULT OF THE INITIAL FAILURE. I AM IN POSSESSION OF THE BLADED DISK AND THE 5 REJECTED BLADES. IN THE INTEREST OF SAFETY I HAVE REACHED OUT TO THE NTSB IN HOPES OF UNBIASED ASSESSMENT OF THIS PROBLEM. I AM AWARE OF 8 ENGINES THAT HAVE HAD 2ND STAGE PT BLADE FAILURES WITH TIME IN-SERVICE RANGING FROM 50 TO 7000 HOURS. THIS COULD HAVE BEEN A FATAL ACCIDENT HAD IT FAILED IN FLIGHT. I WAS LUCKY AS IT HAPPENED ABOUT 20 FEET INTO THE TAKE-OFF ROLL.