AD 2000-21-10

This amendment adopts a new airworthiness directive (AD) that is applicable to CFE Company CFE738-1-1B turbofan engines. This action requires removing certain support assemblies and replacing them with support assemblies that have a new design. This amendment is prompted by a report of the loss of seal retention that resulted in contact between the seal face and the stage 2 high pressure turbine (HPT) rotor disk, and subsequent wear of the stage 2 HPT rotor disk. That condition resulted in separation of the stage 2 HPT wheel rim, and an uncontained failure of the stage 2 HPT rotor wheel. The actions specified in this AD are intended to prevent the static seal from moving forward, which could result in contact between the seal face and stage 2 HPT rotor, wear, and the possibility of an uncontained failure of the stage 2 HPT rotor.

Final rule; request for comments

2000-21-10 CFE Company: Amendment 39-11942. Docket 2000-NE-40-AD.

Applicability:
This AD is applicable to CFE Company CFE738-1-1B turbofan engines with support assembly, part numbers (P/N's) 3050860-2, -3, and -5 through -9 inclusive, installed. These engines are installed on, but not limited to, Dassault Aviation Falcon 2000 series airplanes.

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 (d) 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, unless already done.

To prevent the static seal from moving forward, which could result in contact between the seal face and stage 2 HPT rotor, wear, and the possibility of an uncontained failure of the stage 2 HPT rotor, do the following:

(a) Remove support assembly, P/N 3050860-2, -3, -5 through -9, and replace it with a serviceable seal assembly in accordance with the Accomplishment instructions 2.A.(3) through 2.A.(8)(d) and 2.B.(1) through 2.B.(3) of ASB CFE738 A72-8042, Revision 1, dated September 25, 2000, as follows:

Engines That Have Already Been Inspected
(1) For engines that have been inspected using CFE Company alert service bulletin (ASB) ASB CFE738 A72-8041, dated August 21, 2000, replace the support assembly as follows:

Operating hours time-since new (TSN) on the effective date of this AD
Replace by the earlier of
Fewer than 500 hours TSN.
150 hours time-in-service (TIS) or 90 days after the effective date of this AD.
500 hours to 1,000 hours TSN.
250 hours TIS or 150 days after the effective date of this AD.
More than 1,000 hours TSN.
400 hours TIS or 240 days after the effective date of this AD.

Engines That Have Not Been Inspected
(2) For engines that have not been inspected using CFE Company alert service bulletin (ASB) ASB CFE738 A72-8041, dated August 21, 2000, do EITHER of the following within the earlier of 50 hours TIS or 30 days after the effective date of this AD:

(i) Replace the support assembly with a serviceable support assembly in accordance with the Accomplishment instructions 2.A.(3) through 2.A.(8)(d) and 2.B.(1) through 2.B.(3) of ASB CFE738 A72-8042, and 2.A. or 2.B. of SB CFE738-72-8043, Revision 1, dated October 2, 2000 OR

(ii) Inspect the engine in accordance with the Accomplishment Instructions 2.A. through 2.B.(6) of ASB CFE738-A72-8041, dated August 21, 2000, and then replace the support assembly in accordance with the replacement schedule in paragraph (a)(1) of this AD.

Support Assembly Seal Break-in
(b) After the seal has been replaced, do the support assembly seal break-in procedure in accordance 2.A. (test cell) or 2.B. (on wing) of SB CFE738-72-8043, Revision 1, dated October 2, 2000,

Definition of a Serviceable Part
(c) For the purposes of this AD, a serviceable support assembly is defined as a support assembly with P/N 3050860-10, or -11, P/N 3057005-1 through -5 inclusive, or P/N 3057006-1,or -2.

Alternative Methods of Compliance
(d) 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 itto 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
(e) 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 airplane to a location where the requirements of this AD can be accomplished.

Documents that Have Been Incorporated by Reference
(f) The actions specified in this AD must be done in accordance with the following CFE Company service bulletins:

Document No.
Pages
Revision
Date
ASB CFE738-A72-8041
All
Original
August 21, 2000
Total pages: 26.

ASB CFE738-A72-8042
All
1
September 25, 2000
Total pages: 22.

SB CFE738-72-8043
All
1
October 2, 2000
Total pages: 28.

This incorporation by reference was approved by the Director of the Federal Register in accordance with5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from CFE Company, Data Distribution, MS 64-03/2101-201, P.O. Box 52170, Phoenix, AZ 85972-2170; telephone (602) 365-2493, fax (602) 365-5577. 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.

Effective Date of This AD
(g) This amendment becomes effective on November 8, 2000.

On June 27, 2000, the FAA was notified of an uncontained engine failure of a CFE738-1-1B turbofan engine. A subsequent investigation determined that the rivets that retain the seal to the No. 4 bearing support, part of the support assembly, wore and allowed the seal to migrate forward and contact the stage 2 HPT rotor disk. That contact caused a deep wear groove in the disk web, and subsequent separation of portions of the disk rim from the stage 2 HPT disk, resulting in an uncontained failure of the engine. This condition, if not corrected, could result in wear damage to the stage 2 HPT rotor disk that could result in fracture and a possible uncontained failure of the disk.

Manufacturer's Service Information
The FAA has reviewed and approved the technical contents of the following CFE Company service information:

Alert Service Bulletin (ASB) CFE738-A72-8042, Revision 1, dated September 25, 2000. That ASB describes procedures for replacing the support assembly with a new design support assembly, which has improved static seal retention.
SB CFE738-72-8043, dated October 2, 2000, that provides procedures for the break-in of the engine support assembly seal.
The FAA has also reviewed and approved the technical contents of ASB CFE738-A72-8041, dated August 21, 2000, that describes procedures for borescope inspection of:
The stage 2 HPT rotor disk for contact rubs.
The rivets that attach the static seal to the bearing frame support to ensure there are no anomalies.
The bearing frame support and static seal to determine if there is a gap between them.
The static seal to determine if there is any distortion or waviness.

Requirements of This AD
Since an unsafe condition has been identified that is likely to exist or develop on other CFE Company CFE738-1-1B turbofan engines of the same type design, this AD is being issued to require replacing existing support assemblies, part numbers (P/N's) 3050860-2, -3, and -5 through -9 inclusive, with new support assemblies, P/N 3050860-10, -11, P/N 3057005-1 through -5 inclusive, or P/N 3057006-1, -2. The replacement of the support assembly must be done in accordance with ASB CFE738-A72-8042, Revision 1, dated September 25, 2000. Break-in of the support assembly seal must be done in accordance with SB CFE738-72-8043, Revision 1, dated October 2, 2000. For engines that have not been borescope inspected using ASB CFE738-A72-8041, dated August 21, 2000, the support assembly must be replaced or borescope inspected within the specified replacement interval for that group. The borescope inspection must be done in accordance with ASB CFE738- A72-8041, dated August 21, 2000.

Immediate Adoption of this AD
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-40-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 bythe 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: