13 November 2001.

See also FAA Airworthiness Directives on the Airbus A300 and GE CF-6 engines:

http://cryptome.org/faa-airbus.txt (Airbus 300)

http://cryptomer.og/faa051801.txt (GE CF-6)

Thanks to FAH:

See also NTSB Safety Recommendation on GE CF-6 engines of December 12, 2000:

http://www.ntsb.gov/recs/letters/2000/A00_121_124.pdf

And news report on disintegration of GE CF-6 engine:

http://www.cincypost.com/business/engine010301.html

12 November 2001. Thanks to FAH.

The Airbus A300 which crashed today near John F. Kennedy Airport in New York had GE CF-6 engines discussed below.

Source: http://www.ntsb.gov/Recs/letters/2000/A00_104.pdf

7283

National Transportation Safety Board
Washington, D.C. 20594

Safety Recommendation

_____________________________________________

Date: August 9, 2000

In reply refer to: A-00-104

Honorable Jane F. Garvey
Administrator
Federal Aviation Administration
Washington, D.C. 20591

In this letter, the National Transportation Safety Board recommends that the Federal Aviation Administration (FAA) take action to address a safety issue concerning uncontained engine failures¹ as a result of cracking and rupture of high pressure compressor (HPC) stage 3-9 spools in Failures of General Electric (GE) CF6-50 and -80 series engines. The Safety Board identified this safety issue during its participation in the Brazilian Centro de Investigaçáo e Prevençáo de Accidentes Aeronauticos’ (CENIPA) investigation² of an uncontained engine failure that occurred at São Paulo, Brazil, on June 7, 2000. Although the investigation is continuing, information gathered thus far has raised serious concerns that warrant immediate action by the FAA.

____________________

1 An uncontained engine failure occurs when an integral part of the engine fails and is ejected through the cowling.

2 The Safety Board is assisting CENIPA with its investigation under the provisions of Annex 13 to the International Convention on Civil Aviation.

On June 7, 2000, Varig Brasil Airlines flight 886, a Boeing 767-241ER airplane, equipped with GE CF6-80C2B2 engines, experienced an uncontained failure of the HPC stage 3-9 spool in the No. 2 (right) engine during takeoff at São Paulo, Brazil. The airplane was departing São Paulo on a regularly scheduled passenger flight to Lima, Peru. The flight crew reported that at a speed of about 60 knots, they heard a loud bang. They rejected the takeoff and stopped the airplane on the runway. The copilot opened the right-side cockpit window to look out and advised the pilot that there was a fire around the right main landing gear. The flight crew reported that they then attempted to taxi clear of the fire but stopped the airplane on the runway again when they realized it was the engine that was on fire and ordered an evacuation. Although the flight crew discharged both fire bottles into the No. 2 engine nacelle, the fire continued until it was extinguished by airport fire department personnel.³ Of the 2 pilots, 11 flight attendants, and 178 passengers on board, 4 passengers were injured during the evacuation.

____________________

3 The fire warning did not activate until some time after the event occurred. The failure of the fire warning system to activate is under investigation.

Examination of the airplane revealed that the fuselage forward of the right main landing gear was penetrated, but the passenger compartment was not. There was no damage to any aircraft systems. The underside of the right wing adjacent to the No. 2 engine strut was damaged by heat from the fire. The fire was caused by fuel leaking from the fuel inlet line, which was pulled out of the fuel pump by the outward movement of the HPC case when the spool ruptured. Although the wing had numerous impact marks, it was not penetrated by any debris.

Examination of the engine revealed that the HPC case had an almost 360° rupture between the stage 5 variable stator vanes and the stage 8 compressor bleed air ports. The stage 6, 7, and 8 disks and a portion of the rim and web of the stage 9 disk had separated from the rest of the HPC stage 3-9 spool and were ejected radially outward from the engine. Approximately 95 percent of the ejected pieces of the HPC stage 3-9 spool were recovered.

The ruptured HPC stage 3-9 spool is a rotor one-piece component machined from a single forging⁴ of Ti-6-2-4-2 titanium alloy and composed of disks joined together with integral spacer segments and end flanges (see figure 1). According to Varig Airlines’ maintenance records, the ruptured HPC stage 3-9 spool, part number 9380M28P05 and serial number VOL02558, had accumulated 37,755 hours and 9,948 cycles since new (CSN). Varig’s maintenance records also show that, on September 22, 1997, at 8,907 hours and 2,375 cycles before the rupture, the entire spool underwent a fluorescent penetrant inspection (FPI)⁵ and the disk bores underwent an ultrasonic inspection⁶ at Varig Brasil Airlines’ engine shop.⁷ No defects were noted during those inspections.

____________________

4 The ruptured HPC stage 3-9 spool was made from a one-piece 13-inch diameter billet. (A billet is a semifinished round product from which a part is forged.) In the past, GE has also made HPC stage 3-9 spools from one-piece 16-inch diameter billets, two-piece 9- and 10-inch diameter billets, and two-piece 8-inch diameter billets. In 1999, GE began producing five-piece HPC stage 3-9 spools, made of four pieces (stages 3 through 5, 6, 7, and 8) of Ti 6-4 titanium alloy (containing 6 percent aluminum and 4 percent vanadium) and one piece of Ti 6-2-4-2 titanium alloy (containing 6 percent aluminum, 2 percent tin, 4 percent zirconium, and 2 percent molybdenum).

5 During FPI, a fluorescent dye is applied to the surface of the part. The dye penetrates cracks and leaves a surface indication that is detectable with ultraviolet light.

6 Ultrasonic inspection is a nondestructive testing (NDT) method in which high-frequency sound waves are projected into a solid object to detect and locate subsurface flaws.

7 On October 7, 1998, GE Engines Services formed a joint venture with Varig Brasil Airlines, and the engine overhaul facility was renamed GE Varig.

In addition, the record sheet for the FPI inspection was annotated to indicate that the inspection was accomplished in accordance with GE’s best practices⁸ for FPI of deep disk spools. A review of the HPC stage 3-9 spool FPI process at GE Varig revealed that it conformed with GE’s best practices for FPI of deep disk spools. According to the FPI shop personnel, the process had not changed from what was accomplished when Varig Brasil Airlines operated the engine overhaul facility.

____________________

8 In 1995, GE sent an all operators wire to operators of CF6-6, -50, -80A, -80C, and -80E engines that recommended using support equipment to hold the stage 3-9 spools horizontally when dipping them into the penetrant solution and to rotate the spool in the solution to ensure 100 percent coverage.

Metallurgical examination⁹ of the Varig 3-9 spool revealed a fracture that originated in the stage 7 web from a 0.12 by 0.04-inch subsurface area of quasi-cleavage (rather than a specific point of origin).¹⁰ From the origin area, the fracture propagated in a combination of low cycle fatigue and quasi-cleavage radially inward toward the bore and outward toward the rim and dovetail blade slots, reaching an overall length of about 2.6 inches, before the spool separated. Metallographic examination of the web near the area of the fracture’s origin and the bore revealed that the microstructure was comprised of about 75 percent primary alpha with 25 percent transformed beta grains.¹¹ The microstructure of the rim (under the blade slots) was a 50/50 mix of primary alpha and transformed beta grains.

____________________

9 Portions of the metallurgical examination were conducted at Centro Tecnológico da Aeronáutica, San José dos Campos, Brazil; the Safety Board’s materials laboratory, Washington, D.C.; and, with Safety Board participation, at GE’s materials laboratory, Cincinnati, Ohio.

10 Quasi-cleavage is a brittle fracture mode in which separation occurs largely along crystallographic planes.

11 Primary alpha and transformed beta grains are types of crystallographic structure. Ti-6-2-4-2 should have a homogeneous 50/50 mix of primary alpha and transformed beta grains, with a random crystallographic orientation.

Electron backscatter diffraction¹² of the origin region revealed colonies of primary alpha grains aligned such that their basal planes¹³ were nearly perpendicular to the hoop stress.¹⁴ The scanning electron microscope (SEM) examination of the fracture surface further revealed that the morphology of the fracture away from the origin was predominately quasi-cleavage with random patches of classical fatigue striations. The quasi-cleavage fracture features observed on the fracture surface during metallurgical examination and the highly aligned primary alpha crystal structure are indicative of dwell-time fatigue (DTF).¹⁵

____________________

12 Electron backscatter diffraction, or orientation imaging, is a technique that can use the electron backscatter patterns generated by a scanning electron microscope to determine crystallographic orientation of a material.

13 The basal plane is one of the planes in the unit cell of the primary alpha grains of the titanium material.

14 Hoop stress is the circumferential stress within ring-shaped parts.

15 DTF is a fracture mechanism in which progressive crack growth occurs during cyclic loading and also over time during sustained peak-stress loading. DTF occurs when there is large concentration, or colony, of primary alpha grains that are crystallographically aligned so the primary alpha grain’s basal plane is perpendicular to the primary stress field.

The examination of the fracture surface with the SEM revealed approximately 18,000 striations from the origin area to the end of the progressive growth region.¹⁶ On the basis of the metallurgical examination, it was determined that the crack had broken through the surface and was estimated to be about 0.3 to 0.6 inch long on the stage 7 web surface at the time of the last FPI but had not been detected.

____________________

16 GE stated that a DTF crack actually advances 2 or 3 striations per flight cycle because of the high thrust settings required for reverse, takeoff power, and certain types of approaches. (GE reported that because of the high air traffic density at airports in the United States and Europe, airplanes approaching to land at airports in these locations have to maintain high power settings when they level off at intermediate altitudes. GE further reported that airplanes operating into South American airports, where the air traffic density is not as high, typically do not have to level off at intermediate altitudes.)

According to nondestructive test (NDT) literature, the probability of detection of a 0.3 to 0.6 inch-long surface defect when looking directly at the surface is about 83 to 89 percent, respectively.¹⁷ Although GE reported during the investigation of a previous 3-9 spool rupture¹⁸ that inspections had detected DTF in at least 21 spools, GE fracture mechanics personnel recently stated that, to their knowledge, FPI has never detected a DTF crack on the interior surfaces of an HPC stage 3-9 spool.¹⁹ This statement and the circumstances of the Varig Airlines HPC stage 3-9 spool failure suggest that FPI of the interior surfaces of an HPC stage 3-9 spool may be inadequate to detect cracks that are not in the inspector’s direct line of sight.

____________________

17 Rummel, Ward D.; Matzkanin, George A. 1996. Nondestructive Evaluation (NDE) Capabilities Data Book. Appendix C, Data Set PTAA01L-A. Nondestructive Testing Information Analysis Center, Texas Research Institute Austin, Inc., Austin, Texas.

18 In 1998, the Safety Board assisted the Canadian Transportation Safety Board in its investigation of an uncontained HPC stage 3-9 spool failure at Beijing, China, in a CF6-80C2B6F engine that was installed on a Canadian Airlines International Boeing 767-300ER.

19 Much of the interior surface of an HPC stage 3-9 spool cannot be seen directly; therefore, the inspection of the spool’s disk webs requires the use of a mirror in addition to an ultraviolet light source.

The Safety Board has assisted with the investigations of other uncontained HPC stage 3-9 spool failures in which then-current inspection methods were found deficient. In 1995, the Safety Board assisted the Egyptian Civil Aviation Authority in its investigation of an uncontained failure at Cairo, Egypt, of a CF6-50C2 engine that was installed on an EgyptAir A300B4 airplane. The failure in the EgyptAir engine was attributed to a nitrogen-stabilized hard alpha inclusion²⁰ in the stage 6 disk web. The investigation revealed that engine overhaul shops were dipping HPC stage 3-9 spools into the fluorescent penetrant solution vertically and that this procedure permitted a bubble of air to become trapped under the disk web, thus preventing the fluorescent penetrant solution from contacting the entire interior surface of an HPC stage 3-9 spool. As a result of the EgyptAir investigation, GE issued the all operators wire that detailed FPI best practices for deep disk spools.

____________________

20 Hard alpha inclusions are anomalies in titanium alloys that usually form during the initial melting of the raw materials and are caused by localized excess amounts of either oxygen or nitrogen that have been introduced through atmospheric reaction with titanium in the molten state.

In 1998, the HPC stage 3-9 spool failure in the Canadian Airlines engine was attributed to a DTF fracture that occurred in the stage 3 rim below the dovetail blade slot. The investigation revealed that the FPI and ultrasonic inspection techniques performed on the spool 4 years before it failed did not provide 100 percent inspection coverage of the spool. The Safety Board is aware of 10 other CF6-50 and -80 series engines that have experienced ruptured HPC stage 3-9 spools from either hard alpha inclusions or DTF.²¹

____________________

21 Of these 10, all were uncontained engine failures, six occurred because of hard alpha inclusions, and four occurred because of DTF. The Safety Board does not have any information about whether FPI failed to detect the cracks that led to these failures.

As a result of the findings in the Canadian Airlines International investigation, the Safety Board issued Safety Recommendation A-98-27 requesting the FAA to require GE to develop and implement improved inspection techniques that will provide 100 percent coverage of high-stress areas of the CF6-50 and -80 series HPC stage 3-9 spool and maximum coverage possible for all other areas. In response, the FAA issued Airworthiness Directive (AD) 99-24-15 on October 18, 1999, which requires an ultrasonic inspection of the disk bores and webs and an eddy current inspection²² of the dovetail slots for the CF6-50 and -80 series HPC stage 3-9 spool.²³

____________________

22 Eddy current inspection is an NDT method for detecting surface cracks in which an electromagnetic field is induced into a metal part by an external coil carrying an alternating current. If the coil passes over a crack, the magnetic field is altered and induces a voltage in a second coil. The induced voltage is displayed on an instrument to indicate the presence of a crack.

23 AD 99-24-15 provides a complex schedule for the ultrasonic and eddy current initial and recurring inspections that is based on the engine model that the spool operated in, the spool’s CSN and last inspection, and the billet size from which the spool was made.

GE’s recommended best practices for FPI notwithstanding, the Safety Board remains concerned that the FPI process is inadequate to inspect the interior surfaces of the HPC stage 3-9 spool. The Board is also concerned that the in-service HPC stage 3-9 spools that have not yet been inspected in accordance with AD 99-24-15 may have undetected cracks that could propagate to critical length and rupture. Such ruptures, if uncontained, could result in a catastrophic accident.

Therefore, the National Transportation Safety Board recommends that the Federal Aviation Administration:

Immediately issue an airworthiness directive (AD) to require the expeditious removal from service of CF6-50 and -80 series engines with high pressure compressor stage 3-9 spools that are most at risk of rupturing and inspect those spools in accordance with AD 99-24-15 and engine manual instructions. (Class 1, Urgent Action) (A-00-104)

Chairman HALL and Members HAMMERSCHMIDT, GOGLIA, BLACK and CARMODY concurred in this recommendation.

Original Signed

By: Jim Hall
Chairman

Source: http://av-info.faa.gov/ad/NE00/001612.htm

[4910-13-U]

DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration

14 CFR Part 39 [65 FR 50623 8/21/2000]

[Docket No. 2000-NE-31-AD; Amendment 39-11868; AD 2000-16-12]

RIN 2120-AA64

Airworthiness Directives; General Electric Company CF6-45, -50, -80A, -80C2, and –80E1 Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

SUMMARY: This amendment adopts a new airworthiness directive (AD) that is applicable to General Electric Company (GE) CF6-45, -50, -80A, -80C2, and -80E1 turbofan engines with certain high pressure compressor rotor (HPCR) stage 3-9 spools installed. This action requires initial ultrasonic and eddy current inspections of certain HPCR stage 3-9 spools for cracks. This amendment is prompted by an uncontained failure of an HPCR 3-9 spool. The actions specified in this AD are intended to detect cracks which can cause separation of the HPCR stage 3-9 spool and result in an uncontained engine failure.

DATES: Effective September 5, 2000. The incorporation by reference of certain publications listed in the rule is approved by the Director of the Federal Register as of September 5, 2000.

Comments for inclusion in the Rules Docket must be received on or before October 20, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2000-NE-31-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may also be sent via the Internet using the following address: "9-ane-adcomment@faa.gov". Comments sent via the Internet must contain the docket number in the subject line.

The service information referenced in this AD may be obtained from General Electric Company via Lockheed Martin Technology Services, 10525 Chester Road, Suite C, Cincinnati, Ohio 45215, telephone (513) 672-8400, fax (513) 672-8422. This information may be examined at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Chris Gavriel, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone: (781) 238-7147, fax: (781) 238-7199.

SUPPLEMENTARY INFORMATION: On June 7, 2000, a Boeing 767 experienced an uncontained engine failure of a CF6-80C2 engine during takeoff. That failure resulted in a rejected takeoff. Results of an investigation indicate that the failure was due to a crack that was located in the web of the 7^th stage of the spool. The FAA has issued airworthiness directive (AD) 99-24-15 (64 FR 66554; November 29, 1999) that was effective on January 28, 2000, that requires an inspection program that includes an initial inspection of bores and webs of certain CF6 HPCR 3-9 spools at the next piece-part exposure after 1000 cycles-since-new (CSN). Since that AD was issued, additional data suggests that the compliance time for the initial inspection is not adequate. This AD will decrease the compliance times for the initial inspection for those spools. This AD does not reduce the initial inspection time for HPCR 3-9 spools part numbers 1333M66G10, 1782M22G04, 1854M95P08, 9136M89G28, and 9136M89G29 because of differences in manufacturing processes. The repetitive inspection schedule required by AD 99-24-15 remains in place for all HPCR 3-9 spools affected by that AD. These cracks, if not detected, could result in HPCR stage 3-9 spool separation, which can result in an uncontained engine failure and airplane damage.

Manufacturer’s Service Information

The FAA has reviewed and approved the technical contents of the following GE Alert Service Bulletins (ASB’s):

• ASB CF6-50 72-A1108, Revision 3, dated November 12, 1999

• ASB CF6-80A 72-A0678, Revision 3, dated November 12, 1999

• ASB CF6-80C2 72-A0812, Revision 2, dated October 28, 1999

• ASB CF6-80C2 72-A0848, Revision 5, dated August 3, 2000

• ASB CF6-80E1 72-A0135, Revision 1, dated October 28, 1999

• ASB CF6-80E1 72-A0126, Revision 3, dated August 3, 2000

Those ASB’s describe procedures for eddy current and ultrasonic inspections of HPCR stage 3-9 spools for cracks.

Determination of an Unsafe Condition

Since an unsafe condition has been identified that is likely to exist or develop on other engines of the same type design, this AD is being issued to detect cracks which can cause separation of the HPCR stage 3-9 spool and result in an uncontained engine failure. This AD requires an initial inspection of spools with 10,500 or more CSN, within 500 cycles-in-service (CIS) after the effective date of this AD, by the next engine shop visit, or by May, 31, 2001, whichever occurs first. This AD also requires an initial inspection of spools with 7,000 CSN to 10,499 CSN within 1,000 CIS after the effective date of this AD, by the next shop visit, or by July 29, 2001, whichever occurs first. These initial inspections qualify the HPCR 3-9 spool as having been previously inspected when determining the repetitive inspection schedules under AD 99-24-15. The actions are required to be accomplished in accordance with the alert service bulletins described previously.

Immediate Adoption

Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.

Comments Invited

Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 2000-NE-31-AD." The postcard will be date stamped and returned to the commenter.

Regulatory Impact

This proposed rule does not have federalism implications, as defined in Executive Order No. 13132, because it would not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Accordingly, the FAA has not consulted with state authorities prior to publication of this proposed rule.

The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979).

If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39 - AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

§39.13 [Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

AIRWORTHINESS DIRECTIVE REGULATORY SUPPORT DIVISION P.O. BOX 26460 OKLAHOMA CITY, OKLAHOMA 73125-0460

U.S. Department of Transportation Federal Aviation Administration

AD's are posted on the internet at http://av-info.faa.gov

The following Airworthiness Directive issued by the Federal Aviation Administration in accordance with the provisions of Title 14 of the Code of Federal Regulations (14 CFR) part 39, applies to an aircraft model of which our records indicate you may be the registered owner. Airworthiness Directives affect aviation safety and are regulations which require immediate attention. You are cautioned that no person may operate an aircraft to which an Airworthiness Directive applies, except in accordance with the requirements of the Airworthiness Directive (reference 14 CFR part 39, subpart 39.3).

2000-16-12 General Electric Company: Amendment39-11868. Docket 2000-NE-31-AD.

Applicability

This airworthiness directive is applicable to General Electric Company (GE) CF6-45, -50, -80A, -80C2, and -80E1 turbofan engines with high pressure compressor rotor stage 3-9 spools with the following part numbers (P/N’s). These engines are installed on, but not limited to, Airbus A300, A310, and A330 series, Boeing 747 and 767 series, and McDonnell Douglas DC-10 and MD-11 series airplanes.

Engine Model	HPCR 3-9 Spool P/N
CF6-45/50 Series Engines	9136M89G02, 9136M89G03, 9136M89G06, 9136M89G07 9136M89G08, 9136M89G09, 9136M89G17, 9136M89G18, 9136M89G19, 9136M89G21, 9136M89G22, 9136M89G27, 9273M14G01, 9331M29G01, 9253M85G01, 9253M85G02
CF6-80A Series Engines	9136M89G10, 9136M89G11, 9136M89G20, 9136M89G21, 9136M89G22, 9136M89G27
CF6-80C2 Series Engines	1333M66G01, 1333M66G03, 1333M66G07, 1333M66G09, 1781M52P01, 1781M53G01, 1854M95P01, 1854M95P02, 1854M95P03, 1854M95P04, 1854M95P05, 1854M95P06, 1854M95P07, 9380M28P05
CF6-80E1 Series Engines	1669M22G01, 1669M22G03, 1782M22G01, 1782M22G02

Note 1: This airworthiness directive (AD) applies to each engine identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For engines that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (j) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance

Compliance with this AD is required as indicated below, unless already done.

To detect cracks which can cause separation of the HPCR stage 3-9 spool and result in an uncontained engine failure, perform the following inspections:

CF6-45/50 Series Engines

(a) For HPCR stages 3-9 spools installed in CF6-45/50 series engines that have not been inspected in accordance with AD 99-24-15, do the following:

Number of Cycles-Since-New (CSN)	Action	By the earliest of
(1) More than 7,000 CSN but fewer than 10,500 CSN after the effective date of this AD.	Eddy current and ultrasonic inspect bores for cracks in accordance with ASB 72-A1108, Revision 3, dated November 12, 1999.	(i) Within the next 1,000 cycles-in-service (CIS) after the effective date of this AD, or (ii) At the next engine shop visit (ESV) after the effective date of the AD, or (iii) Before July 29, 2001.

Number of Cycles-Since-New (CSN)	Action	By the earliest of
(2) 10,500 or more CSN, after the effective date of this AD, on HPCR 3-9 spools P/N 9136M89G02, 9136M89G03, 9136M89G06, 9136M89G07, 9136M89G08, 9136M89G09, 9136M89G17, 9136M89G18, 9273M14G01, 9331M29G01, 9253M85G01, 9253M85G02.	Eddy current and ultrasonic inspect bores for cracks in accordance with ASB 72-A1108, Revision 3, dated November 12, 1999.	(i) Within the next 500 CIS after the effective date of this AD, or (ii) At the next ESV after the effective date of the AD, or (iii) Before May 31, 2001.
(3) 10,500 or more CSN, after the effective date of this AD, on HPCR 3-9 spools P/N 9136M89G19, 9136M89G21, 9136M89G22, 9136M89G27	Replace with a serviceable HPCR 3-9 spool.	(i) Within the next 500 CIS after the effective date of this AD, or (ii) At the next ESV after the effective date of the AD, or (iii) Before May 31, 2001.

(b) Remove any HPCR 3-9 spool from service that equals or exceeds the reject criteria established by ASB 72-A1108, Revision 3, dated November 12, 1999; and replace it with a serviceable spool before further flight.

CF6-80A Series Engines

(c) For HPCR stages 3-9 spools installed in CF6-80A series engines that have not been inspected in accordance with AD 99-24-15, do the following:

Number of Cycles-Since-New (CSN)	Action	By the earliest of
(1) More than 7,000 CSN but fewer than 10,500 CSN, after the effective date of this AD.	Eddy current and ultrasonic inspect bores for cracks in accordance with ASB 72-A0678, Revision 3, dated November 12, 1999.	(i) Within the next 1,000 CIS after the effective date of this AD, or (ii) At the next ESV after the effective date of the AD, or (iii) Before July 29, 2001.
(2) 10,500 or more CSN, after the effective date of this AD, on HPCR 3-9 spools P/N 9136M89G10, 9136M89G11.	Eddy current and ultrasonic inspect bores for cracks in accordance with ASB 72-A0678, Revision 3, dated November 12, 1999.	(i) Within the next 500 CIS after the effective date of this AD, or (ii) At the next ESV after the effective date of the AD, or (iii) Before May 31, 2001.
(3) 10,500 or more CSN, after the effective date of this AD, on HPCR 3-9 spools P/N 9136M89G20, 9136M89G21, 9136M89G22, 9136M89G27	Replace with a serviceable HPCR 3-9 spool.	(i) Within the next 500 CIS after the effective date of this AD, or (ii) At the next ESV after the effective date of the AD, or (iii) Before May 31, 2001.

(d) Remove any HPCR 3-9 spool from service that equals or exceeds the reject criteria established by ASB 72-A0678, Revision 3, dated November 12, 1999, and replace it with a serviceable spool before further flight.

CF6-80C2 Series Engines

(e) For HPCR stages 3-9 spools installed in CF6-80C2 series engines that have not been inspected in accordance with both ASB 72-A0812, Revision 2, dated October 28, 1999; and ASB 72-A0848, Revision 5, dated August 3, 2000; or AD 99-24-15, do the following:

Number of Cycles-Since-New (CSN)	Action	By the earliest of
(1) More than 7,000 CSN but fewer than 10,500 CSN, after the effective date of this AD.	Eddy current and ultrasonic inspect the bores and webs for cracks in accordance with ASB 72-A0812, Revision 2, dated October 28, 1999; and ASB 72-A0848, Revision 5, dated August 3, 2000.	(i) Within the next 1,000 CIS after the effective date of this AD, or (ii) At the next ESV after the effective date of the AD, or (iii) Before July 29, 2001.
(2) 10,500 or more CSN, after the effective date of this AD.	Replace with a serviceable HPCR 3-9 spool.	(i) Within the next 500 CIS after the effective date of this AD, or (ii) At the next ESV after the effective date of the AD, or (iii) Before May 31, 2001.

(f) Remove any HPCR 3-9 spool from service that equals or exceeds the reject criteria established by ASB 72-A0812, Revision 2, dated October 28, 1999; and ASB 72-A0848, Revision 5, dated August 3, 2000, and replace it with a serviceable spool before further flight.

CF6-80E1 Series Engines

(g) For HPCR stages 3-9 spools installed in CF6-80E1 series engines that have not been inspected in accordance with both ASB 72-A0135, Revision 1, dated October 28, 1999; and ASB 72-A0126, Revision 3, dated August 3, 2000; or AD 99-24-15, do the following:

Number of Cycles-Since-New (CSN)	Action	By the earliest of
(1) More than 7,000 CSN but fewer than 10,500 CSN, after the effective date of this AD.	Eddy current and ultrasonic inspect the bores and webs for cracks in accordance with ASB 72-A0126, Revision 3, dated August 3, 2000, and ASB 72-A0135, Revision 1, dated October 28, 1999.	(i) Within the next 1,000 CIS after the effective date of this AD, or (ii) At the next ESV after the effective date of the AD, or (iii) Before July 29, 2001.
(2) 10,500 or more CSN after the effective date of this AD.	Replace with a serviceable HPCR 3-9 spool.	(i) Within the next 500 CIS after the effective date of this AD, or (ii) At the next ESV after the effective date of the AD, or (iii) Before May 31, 2001.

(h) Remove any HPCR 3-9 spool from service before further flight that equals or exceeds the reject criteria established by ASB 72-A0135, revision 1, dated October 28, 1999; or ASB 72-A0126, revision 3, dated August 3, 2000, and replace it with a serviceable spool.

Definitions

(i) For the purpose of this AD, an ESV is defined as any time an engine is introduced into a shop for the separation of a major engine flange.

Alternative Methods of Compliance

(j) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Engine Certification Office (ECO). Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, ECO.

Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the ECO.

Special Flight Permits

(k) Special flight permits may be issued in accordance with §§ 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the aircraft to a location where the requirements of this AD can be accomplished.

(l) The inspection shall be done in accordance with the following GE Alert Service Bulletins:

The incorporations by reference of ASB’s No. CF6-50 72-A1108, Revision 3; CF6-80A 72-A0678, Revision 3; CF6-80C2 72-A0812, Revision 2; and CF6-80E1 72-A0135, Revision 1, were approved by the Director of the Federal Register on January 28, 2000 (64 FR 66554; November 29, 1999). The incorporations by reference of ASB’s CF6-80C2 72-A0848, Revision 5; and CF6-80E1 72-A0126, Revision 3 were approved by the Director of the Federal Register on September 5, 2000 in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from General Electric Company via Lockheed Martin Technology Services, 10525 Chester Road, Suite C, Cincinnati, Ohio 45215, telephone (513) 672-8400, fax (513) 672-8422. Copies may be inspected at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

(m) This amendment becomes effective on September 5, 2000.

FOR FURTHER INFORMATION CONTACT: Chris Gavriel, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone: (781) 238-7147, fax: (781) 238-7199.

Issued in Burlington, Massachusetts, on August 10, 2000.

David A. Downey, Assistant Manager, Engine and Propeller Directorate, Aircraft Certification Service.

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