As to confidence long term, would it not be better if the failure had a common cause?

As in, "The GEnx has a tendency to come apart, for varied reasons..."

Or, "Common cause, remedied...."

Carry on....

More trouble ahead?

Investigators find cracks in second Dreamliner engine - CNN.com

The CNN story is ambiguous as to whether the second 787/GEnx-1B event is a new failure mode -

But post #8 in this thread allows that it is siimilar (FMS crack) to the first. To date, only the 748/GEnx-2B Shanghai case is different, and I don't think teardown results have yet been released for that case.

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).

As of yesterday, 10-04-12, Reuters is reporting that GE has located the problem that disabled the 2B GEnx on the 747 in Shanghai, Atlas.

It appears the LowPressure Turbine nozzle was installed incorrectly. No damage forward of the nozzle, and the incident seems isolated to this occurrence.

I apologize for not linking the story here, operator malfunction.

GE Engine Failure Caused by Assembly Error
 

By KATE LINEBAUGH - WSJ
General Electric Co. GE +0.86% said the failure of an aircraft engine on a Boeing Co.BA +1.52% 747-8 in Shanghai was caused by an assembly error, adding a second source of concern about the company's newest engine.

GE told aircraft operators to complete a one-time, hour long inspection of its fleet of 120 GEnx engines in the next 90 days. The inspection will check whether a part that directs air into the rotating blades of the (LP) turbine was properly installed.

The initial findings indicate that "a stage-one nozzle may have been improperly assembled and became dislodged," a spokeswoman for the National Transportation Safety Board said. "Efforts are continuing to determine the reason for these observations."

The problem is the second found by GE with the GEnx, which is fitted on Boeing's Dreamliner and 747s and whose design is at the heart of the company's coming generation of aircraft engines. The mishaps are a black eye for the world's largest jet-engine maker at a time when the aircraft market is booming and the battle among engine makers is fierce.

Unless these issues are "resolved relatively soon and decisively, they could cause some problems with customers refusing delivery of aircraft," said William Storey, president of Teal Group, a Fairfax, Va.-based research firm specializing in aerospace and defense...

barit1

"General Electric Co. GE +0.86% said the failure of an aircraft engine on a Boeing Co.BA +1.52% 747-8 in Shanghai was caused by an assembly error, adding a second source of concern about the company's newest engine."

Howdy. This is confusing to me. The impression I have gotten from reading the trades is that the two engines are separate in concern. Now the second problem appears to be piggy backing on the embrittlement problem.

What is your take, barit1?

Lyman,

The B-787 engine problem in Charleston was due to a mid-shaft cracking problem. The B747 engine problem in Shanghai was due to an assembly problem where a nozzle vane became loose during TO. The engines are different in several respects and the problems are different. Only the press assumed the Shanghai incident to be the same as the Charleston incident.

Lyman - see posts #86 and #91.

Two separate problems which arguably are not one-offs.

The GE challenge is to identify the two different suspect populations and recommend inspection procedures to minimize any chance of combinations on the same aircraft.

Working on a level of finding each and every one is fine, but the timing must preclude the higher risk scenario of two of any combination on the same aircraft.

I expect that is what is being worked and all we will see on the sidelines is the effect of the inspections and removals

lomapaseo

Thanks. That makes it quite clear then. I sensed that from some posts I read, it was implied "two different engines" (1B/2B), and that the one inspection exonerated the other fault, by virtue of design differences/type.

So all nx engines are being inspected for both observed failures.

Given that the two GEnx subtypes are more alike than they are different, that is the only sane course of action. :uhoh:

So a forthcoming AD regarding a shaft coupling failure is followed by an in service manufacturing process failure that halts a flight. The one preceeding, the shaft problem, is being remedied with new shafts, and the second with inspections to eliminate possibilities of poor manufacture remaining on wing.

Are we talking about the GE? Or the TRENT?

Eerie...

lomapaseo:
"These things have a way of working themselves out within a month.

Give me a ring if anything New"

willdo

These things have a way of working themselves out within a month.

Give me a ring if anything New

Will these latest engine problems be causing any more delays to deliveries?

I only ask, as one airline I was expecting to have received theirs by now is now looking at mid November at the earliest.

TURIN
 

Which airline was that?

QATAR.

It was due in July.

Turin.
Via the Tuesday Reuters article, the chief executive of Qatar said the airline would not accept any of the sixty 787s ordered until "The engines have been modified".

Qatar, took delivery of its first B787 on Friday.
Will shortly after be flown to Victorville for work on the IFE system, returning for a formal delivery ceremony around 17th or 18th, before the aircraft is flown away to Doha.:ok:

Were the engines refit with the new shafts?