AD 98-23-06

This amendment adopts a new airworthiness directive (AD) that is applicable to General Electric Aircraft Engines (GEAE) CJ610 series turbojet and CF700 series turbofan engines. This action requires operators to remove and replace with serviceable parts unapproved combustion liner assemblies prior to further flight. This amendment is prompted by findings that unapproved combustion liner assemblies are installed on the affected engines. The actions specified in this AD are intended to prevent combustor liner cracking at multiple locations, progressing to liner fragmenting and combustor casing burnthrough, which could result in an engine fire.

Final rule; request for comments.

98-23-06 General Electric Aircraft Engines: Amendment 39-10870. Docket 98-ANE-60-AD.
Applicability: General Electric Aircraft Engines (GEAE) CJ610 series turbojet and CF700 series turbofan engines, with combustor liner assemblies, part number (P/N) 6008T94G03, identified by serial number (S/N) or otherwise specified in Appendix 1 of this AD, installed. These engines are installed on but not limited to the following aircraft: Dassault-Aviation Fan Jet Falcon 20 series, Sabreliner NA265 series, Learjet 20 series, Israel Aircraft Industries Westwind series, Hansa Jet, Aero Commander Jet Commander. Appendix 1

Serial Number Combustion Liners (sorted alphanumerically)

1763
GGM82
181
GGM830
1939
GGMB7019
318-1
GGMH2135
318-2
GGMM1218
35
GKAPL77
497
OG2250
564
ST000891
900206
ST00247
910205
ST00276
GGM00028
ST00303
GGM00518
ST00391
GGM00536
ST00488
GGM00585
ST00623
GGM00893
ST00808
GGM59515
ST00840
GGM59675
ST00896
GGM59801
ST01042
GGM60028
ST01142

Additional Liners, with Serial Number Markings unknown
Any other serial number combustion liner, part number 6008T94G03, following repair or overhaul which included installation of inner shell, P/N 5016T30G02, or installation of outer shell, P/N 6008T95G01, during the period from May 16, 1997, through February 13, 1998, and if approved for return to service by: The Jet Engine Shop (also known as 3d Industries, or 3DI, or identified by Certificate Number CRS J3DR866N), 4553 Keller Springs Road, Dallas, Texas 75248.
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 (b) 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: Required as indicated, unless accomplished previously.
To prevent combustor liner cracking at multiple locations, progressing to liner fragmenting and combustor casing burnthrough, which could result in an engine fire, accomplish the following:
(a) Prior to further flight, for any combustor liner identified by serial number (S/N), or otherwise identified in Appendix 1 of this AD, remove from service and replace with a serviceable part.
(b) 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. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office.
Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office.
(c) Special flight permits may be issued in accordance with sections 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 record search requirements of this AD can be accomplished.
(d) This amendment becomes effective on November 20, 1998.

The Federal Aviation Administration has received reports of premature cracking of unapproved combustor liner assemblies, part number (P/N) 6008T94G03, installed on General Electric Aircraft Engines (GEAE) CJ610 series turbojet and CF700 series turbofan engines. The investigation revealed that combustor liners were repaired using unapproved inner and outer shells manufactured using a substituted material, and with cooling slots, dilution holes, and other geometric features that do not conform to approved drawing requirements, resulting in increased stress levels at these features. The substituted material or the increased stress levels or both can result in reduced combustor life. In addition, because the potential crack origin sites occur at multiple locations surrounding the combustor, including liner cooling slots and dilution holes, adjacent cracks may combine, resulting in liner holes and hot gas discharge from the combustor. Analyses supported by inspections of parts have revealed that unapproved liners will have an unknown service life that could be significantly lower than the inspection interval requirements for approved combustor liners. The FAA has identified 38 combustor liners, identified by serial number (S/N), known to have been repaired using inner or outer shells manufactured by an unknown manufacturer using unknown processes and materials. The FAA has also identified additional combustor liners, with unknown S/N markings, that were repaired in the same way, by a particular certificated repair station. This condition, if not corrected, could result in combustor liner cracking at multiple locations, progressing to liner fragmenting and combustor casing burnthrough, which could result in an engine fire.
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 prevent combustor liner failure. This AD requires removal and replacement of unapproved combustion liner assemblies with serviceable parts prior to further flight.
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 98-ANE-60-AD." The postcard will be date stamped and returned to the commenter.
The regulations adopted herein will not have substantial direct effects 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. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.
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: