787 engine failure in Charleston, SC

[Data Guy]

Those pesky Mid-Shafts

7 Other Mid Shaft failures. Dec 1995 to April 2007.
Notes; Other engine models CF-6s, CF6-50s, CFM56s and CF6-90s.
Only two may be found in NTSB records (Safety Letters, or Accident/Incident database).
Only two (8/18/00 and 12/6/95) had a finding to a cause.
4/1/07. Continental CF6 - 90 series. No Cause. Shop Tear down Report (by QEMY). Source; ASRS report 733184 and SDR # 2007FA0000350 “Upon inspection of the engine, the fan rotated freely, but the LPT did not rotate. BS1 of the engine showed that the HPT was clean, but the LPT was heavily damaged. The engine was shipped to MFG. Initial inspections showed that the fan mid shaft was separated in the axial plane of the HPC S3 disc. The center vent tube was separated in 3 places all aft of FMS separation. An investigation is on going. Shaft Part 1767M75G03." Continental SDR, number and Link > CALA0700137 on 3/20/07. SDR also said investigation by engineering and GE concluded that an omni seal was not installed during engine buildup and that this caused accelerated corrosion of the FMS and subsequent failure. Ed. Note; ASRS Report 733184. No NTSB Accident/Incident rpt --------------------
6/8/06. A-319. CFM56 series. Uncontained Failure. HPT Rear Shaft. No Cause. Source; SDR # 2006FA0000635. “REF: MRD/001/06 - AC suffered an aborted takeoff. Investigation revealed failure and liberation of the HPT rear shaft where a section of material measuring 3.5 inch circumference had liberated around the 3 seal tooth rack. Similar failures have been experienced on engine. Parts are returned to MFG for investigation. Shaft P/N # 9514M71PO4”. Ed Note; No NTSB Accident/Incident Rpt. -------------------------
8/18/00. Carrier UIEA, 747. CF6 -50. Uncontained Failure. Fan Mid Shaft and Stage 4 Disk departed. Cause; air duct. Source; SDR # UIEA0018 . “FLT 7150 - GYE - On takeoff at 400 AGL, Nr 1 engine exploded and had aircraft vibration. Leveled aircraft at 817 feet. Advised tower had an engine fire and declared an emergency. Dumped 30K fuel and returned to GYE. On arrival, determined that Nr 1 engine had an uncontained failure. Analysis of failure indicated airduct failure in area of seventh stiffener. Airduct machined into fan mid-shaft. Fan mid-shaft separated, resulting in uncontained engine failure and stage 4 disk and related hardware departed the engine/aircraft. Duct Part # 9081M40G11”. Ed. Note; No NTSB Accident/Incident Rpt. ---------------------
3/9/98. United DC-10. CF6 - 6. Fan Mid Shaft (FMS) Separated. No Cause. Source; SDR # 98UAL900110 “shut down Nr 3 engine due to aircraft vibration and high temperature indication. Diverted to HNL landed under amber alert. *S/D* the Fan mid-shaft in the engine separated. The primary cause of failure is still under investigation by General Electric”. Ed Note; no further ‘supplemental’ SDR filed. No NTSB Accident/Incident Rpt . ----------------------
10/7/97. Carrier LY2R. 737. CFM56 series. Shutdown On Takeoff. (HPT) Shaft Failed At Seal Teeth. No Cause. Source; SDR # 98ZZZX1899 . “HPT aft shaft failed on takeoff roll at 80 percent N1. HPT aft shaft failed at seal teeth causing extensive damage down stream in the turbine 2nd LPT areas. P/N 9514M71P04.” Ed. Note; No NTSB Accident/Incident Rpt --------------------.
2/22/96. Continental DC-10. CF6 -50. Uncontained failure. Fan Mid Shaft Sheared Off. No Confirmed Cause. Sources; NTSB Safety Letter A-98-125-126, page 4, and SDR # CAL960187 . “A IAH - FLT 0010 - Takeoff was rejected at 100 knots after the Nr 3 engine experienced loss of power. The SDR will remain open for part information pending investigation. Supplement: Preliminary investigation revealed uncontained failure in LPT rotor area. Shop inspection found the fan mid-shaft sheared off. Submitter stated the suspected cause of failure was the HPC rotor air duct failed and rubbed on fan mid-shaft. (x)”. Ed Note; No further ‘supplemental’ SDR and No NTSB Accident/Incident Rpt. -----------------------------
12/6/95. CF6-50. Uncontained Failure. Fan Mid Shaft Failure, rubbing. Cause; Previous Bearing Failure. Sources; NTSB Safety Recommendation Letter A98-125-126. Link > ;http://www.ntsb.gov/recs/letters/1998/A98_125_126.PDF Also a NTSB Accident/Incident Report # NYC96IA036. “The National Transportation Safety Board determines the probable cause(s) of this incident as follows: failure of the number two engine fan mid shaft, due a fatigue fracture caused by a previous bearing failure, and failure of the operator's maintenance personnel to detect the cracks during subsequent inspections”. NTSB Accident/Incident Report. Link > NYC96IA036 Ed. Note; The only NTSB report of a engine bearing Failure. 43 others were SDR Reports.
Source Notes; NTSB Accident/Incident database Link > N T S B - Aviation Accidents - Index of Months search by date.
FAA’s Service Difficulty database and query search; Link > FAA :: SDR Reporting [Service Difficulty Report Query Page] search by SDR # (control number).