01-25054. Airworthiness Directives; General Electric Company CF34 Series Turbofan Engines

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The Federal Aviation Administration (FAA) proposes to supersede an existing airworthiness directive (AD), that is applicable to General Electric Company CF34 series turbofan engines. That AD currently requires revisions to the Engine Maintenance Program specified in the manufacturer's Instructions for Continued Airworthiness (ICA) for General Electric Company (GE) CF34 series turbofan engines. This proposal would modify the airworthiness limitations section of the manufacturer's manual and an air carrier's approved continuous airworthiness maintenance program to incorporate additional inspection requirements. An FAA study of in-service events involving uncontained failures of critical rotating engine parts has indicated the need for mandatory inspections. The mandatory inspections are needed to identify those critical rotating parts with conditions, which if allowed to continue in service, could result in uncontained failures. The actions specified by this proposed AD are intended to prevent critical life-limited rotating engine part failure, which could result in an uncontained engine failure and damage to the airplane.

DATES:

Comments must be received by December 4, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 99-NE-49-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via the Internet must contain the docket number in the subject line. Comments may be inspected at this location by appointment between 8 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT:

Barbara Caufield, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone [phone], fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed 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 above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this action may be changed in light of the comments received.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 99-NE-49-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRM's

Any person may obtain a copy of this NPRM by submitting a request to the FAA, New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 99-NE-49-AD, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

On May 7, 2001, the Federal Aviation Administration (FAA) issued airworthiness directive (AD) 2000-03-03 R1, Amendment 39-12228 (66 FR 26787, May 15, 2001), to require revisions to the Engine Maintenance Program specified in the manufacturer's Instructions for Continued Airworthiness (ICA) for General Electric Company (GE) CF34 series turbofan engines at each piece part exposure exposure.

Additional Inspection Procedures

Since the issuance of that AD, an FAA study of in-service events involving uncontained failures of critical rotating engine parts has indicated the need for additional mandatory inspections. The mandatory inspections are needed to identify those critical rotating parts with conditions, which if allowed to continue in service, could result in uncontained failures. This proposal would modify the airworthiness limitations section of the manufacturer's manual and an air carrier's approved continuous airworthiness maintenance program to incorporate additional inspection requirements.

Proposed Actions

Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would supersede AD 2000-03-03 R1 to add additional inspections for certain critical rotating engine parts at each piece-part opportunity.

Economic Analysis

The FAA estimates that 1022 engines installed on aircraft of U.S. registry would be affected by this proposed AD. The FAA also estimates that it would take approximately 32 work hours per engine to accomplish the proposed inspections, and that the average labor rate is $60 per work hour. Using average shop visit rates, 200 engines are expected to be affected per year. Based on these figures, the total annual cost impact of the proposed AD on U.S. operators is estimated to be $384,000.

Regulatory Analysis

This proposed rule does not have federalism implications, as defined in Executive Order 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.

For the reasons discussed above, I certify that this proposed regulation (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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 removing Amendment 39-12228 (66 FR 26787, May 15, 2001), and by adding a new airworthiness directive:

General Electric Company: Docket No. 99-NE-49-AD. Supersedes AD 2000-03-03 R1, Amendment 39-12228.

Applicability

This airworthiness directive (AD) is applicable to General Electric Company (GE) CF34-3A1 and -3B1 series turbofan engines, installed on but not limited to Bombardier Canadair CL 600-2B19(RJ) aircraft.

Note 1:

This 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 (c) 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 critical life-limited rotating engine part failure, which could result in an uncontained engine failure and damage to the airplane, accomplish the following:

Inspections

(a) Within the next 30 days after the effective date of this AD, revise the CF34 Engine Maintenance Program, Chapter 5-21-00, of the GE CF34 Series Turbofan Engine Manual, SEI-756. For air carrier operations, revise the approved continuous airworthiness maintenance program, by adding the following:

9. CF34-3A1 and CF34-3B1 Engine Maintenance Program—Mandatory Inspection Requirements.

(A) This procedure is used to identify specific piece-parts that require mandatory inspections that must be accomplished at each piece-part exposure using the applicable Chapters referenced in Table 804 for the inspection requirements. The inspection requirements listed in Table 804 are not required for any piece-part exposure resulting when the engine remains on-wing while performing maintenance practice, special procedure Number 41 listed in SEI-756, chapter 72-00-00.

(B) Piece-part exposure is defined as follows: Note: Fan disk piece-part includes the fan disk with the 56 fan pin bushings installed.

(1) For engines that utilize the “On Condition” maintenance requirements: The part is considered completely disassembled to the piece-part level when done in accordance with the disassembly instructions in the GEAE authorized overhaul Engine Manual, and the part has accumulated more than 100 cycles-in-service since the last piece-part opportunity inspection, provided that the part was not damaged or related to the cause for its removal from the engine.

(2) For engines that utilize the “Hard Time” maintenance requirements: The part is considered completely disassembled when done in accordance with the disassembly instructions used in the “Minor Maintenance” or “Overhaul” instructions in the GEAE engine authorized Engine Manual, and the part has accumulated more than 100 cycles-in-service since the last piece-part opportunity inspection, provided that the part was not damaged or related to the cause for its removal from the engine.

C. Refer to Table 804 below for the mandatory inspection requirements.

Table 804.—Mandatory Inspection Requirements

Part nomenclature	Manual/chapter section/subject	Mandatory inspection
Fan Disk (all)	72-21-00, INSPECTION	All areas (FPI). Bores (ECI).
Stage 1 high pressure turbine (HPT) Rotor Disk (all)	72-46-00, INSPECTION	All areas (FPI). Bores (ECI). Boltholes (ECI). Air Holes (ECI).
Stage 2 HPT Rotor Disk (all)	72-46-00, INSPECTION	All Areas (FPI). Bores (ECI).
(a) Boltless Rim Configuration		Boltholes (FPI). Air Holes (FPI).
(b) Bolted Rim Configuration		Boltholes (ECI). Air Holes (ECI).
HPT Rotor Outer Torque Coupling (all)	72-46-00, INSPECTION	All areas (FPI). Bore (ECI).
Forward Fan Shaft (all)	72-21-00, INSPECTION	All Areas (FPI).
Fan Drive Shaft (all)	72-22-00, INSPECTION	All Areas (FPI).
Stage 1 Compressor Rotor Disk (CF34-3A1) or Stage 1 Compressor Rotor Blisk (CF34-3B1) (all)	72-33-00, INSPECTION	All Areas (FPI).
Compressor Forward Shaft (all)	72-33-00, INSPECTION	All Areas (FPI).
Stage 2 Compressor Rotor Disk (all)	72-33-00, INSPECTION	All Areas (FPI).
Stage 3-8 Compressor Rotor Spool (all)	72-33-00, INSPECTION	All Areas (FPI).
Stage 9 Compressor Rotor Disk (all)	72-33-00, INSPECTION	All Areas (FPI).
Compressor Rotor Rear Shaft (all)	72-33-00, INSPECTION	All Areas (FPI).
Compressor Discharge Rotating Seal (all)	72-33-00, INSPECTION	All non-coated Areas (FPI).
Stage 10-14 Compressor Rotor Spool (all)	72-33-00, INSPECTION	All non-coated Areas (FPI).
Turbine Rear Shaft (LPT Rotor) (all)	72-53-00, INSPECTION	All Areas (FPI).
Stage 3 Turbine Disk (all)	72-53-00, INSPECTION	All Areas (FPI).
Stage 4 Turbine Disk (all)	72-53-00, INSPECTION	All Areas (FPI).
Stage 5 Turbine Disk (all)	72-53-00, INSPECTION	All Areas (FPI).
Stage 6 Turbine Disk (all)	72-53-00, INSPECTION	All Areas (FPI).
Turbine Driver Cone (all)	72-53-00, INSPECTION	All Areas (FPI).
FPI = Fluorescent Penetrant Inspection Method
ECI = Eddy Current Inspection”

(b) Except as provided in paragraph (c) of this AD, and notwithstanding the provisions of section 43.16 of the Federal Aviation Regulations (14 CFR 43.16), these mandatory inspections shall be performed only in accordance with the CF34 Engine Maintenance Program, Chapter 5-21-00, of the General Electric Company, CF34 Series Turbofan Engine Manual, SEI-756.

Alternative Method of Compliance

(c) 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 (PMI), 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 AD, if any, may be obtained from the ECO.

Special Flight Permits

(d) 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.

Continuous Airworthiness Maintenance Program

(e) FAA-certificated air carriers that have an approved continuous airworthiness maintenance program in accordance with the record keeping requirement of § 121.369(c) of the Federal Aviation Regulations [14 CFR 121.369(c)] must maintain records of the mandatory inspections that result from revising the CF34 Engine Maintenance Program and the air carrier's continuous airworthiness program. Alternately, certificated air carriers may establish an approved system of record retention that provides a method for preservation and retrieval of the maintenance records that include the inspections resulting from this AD, and include the policy and procedures for implementing this alternate method in the air carrier's maintenance manual required by § 121.369(c) of the Federal Aviation Regulations [14 CFR 121.369(c)]; however, the alternate system must be accepted by the appropriate PMI and require the maintenance records be maintained either indefinitely or until the work is repeated. Records of the piece-part inspections are not required under § 121.380(a)(2)(vi) of the Federal Aviation Regulations [14 CFR 121.380(a)(2)(vi)]. All other operators must maintain the records of mandatory inspections required by the applicable regulations governing their operations.

Note 3:

The requirements of this AD have been met when the engine manual changes are made and air carriers have modified their continuous airworthiness maintenance plans to reflect the Engine Maintenance Program requirements specified in the GE CF34 Series Turbofan Engine Manual.

Issued in Burlington, Massachusetts, on October 1, 2001.

Jay J. Pardee,

Manager, Engine and Propeller Directorate, Aircraft Certification Service.