02-14856. Airworthiness Directives; CFM International CFM56-5, -5A, and -5B Series Turbofan Engines

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The Federal Aviation Administration (FAA) proposes to adopt a new airworthiness directive (AD) that is applicable to CFM International CFM56-5, -5A, and -5B series turbofan engines. This proposal would require establishment of an exhaust gas temperature (EGT) baseline and trend monitoring using the System for Analysis of Gas Turbine Engines (SAGE), or equivalent, as an option to EGT harness replacement, and if necessary, replacement of certain serial numbers (SN's) of EGT harnesses and EGT couplings as soon as a slow and continuous EGT drift downward is noticed after the effective date of this proposed AD. This proposal is prompted by reports of erroneous EGT readings. The actions specified by the proposed AD are intended to prevent unexpected deterioration of critical rotating engine parts due to higher than desired engine operating EGT's.

DATES:

Comments must be received by August 12, 2002.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2001-NE-49-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may be inspected at this location, by appointment, between 8 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. 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. The service information referenced in the proposed rule may be obtained from CFM International, Technical Publications Department, 1 Neumann Way, Cincinnati, OH 45215; telephone [phone]; fax [phone]. This information may be examined, by appointment, at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT:

James Rosa, 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 2001-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. 2001-NE-49-AD, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

The FAA has received several reports of erroneous EGT readings on CFM International CFM56-5, -5A, and -5B series turbofan engines. The manufacturer has determined that the problem is being caused by defects in the EGT harness manufacturing process. EGT harnesses manufactured between September 1998 and July 2000 are suspect for a noncontrolled contamination element, which affected the harness production on a random basis. This condition, if not corrected, could result in unexpected deterioration of critical rotating engine parts due to higher than desired engine operating EGT's.

Manufacturer's Service Information

The FAA has reviewed and approved the technical contents of CFM International service bulletins CFM56-5 S/B 77-0020, dated March 4, 2002, and CFM56-5B S/B 77-0008, dated March 4, 2002, that list affected EGT harnesses and EGT couplings by serial number (SN), and specify applicable engine manual sections for referencing replacement procedures. The actions would be required to be done in accordance with the SB's described previously.

FAA's Determination of an Unsafe Condition and Proposed Actions

Since an unsafe condition has been identified that is likely to exist or develop on other CFM International CFM56-5, -5A, and -5B series turbofan engines of the same type design, the proposed AD would require:

• Establishment of an EGT baseline and SAGE trend monitoring, or equivalent, as an option to EGT harness replacement of affected EGT harnesses and EGT couplings, with continuation of parts in-service that repeatedly pass the trend monitoring, or
• Replacement of affected EGT harnesses and EGT couplings not being trend monitored, within 250 hours of operation after the effective date of this AD. This limit is based on manufacturer's analysis.
• Replacement of affected EGT harnesses and EGT couplings as soon as slow and continuous temperature drift downward (i.e. cooler indication) of 10°C or more from baseline is observed, without a corresponding change in other associated engine parameters such as N1 (LPT rotor speed), N2 (HPT rotor speed), and fuel flow.

Economic Analysis

There are approximately 886 CFM International CFM56-5, -5A, and -5B series turbofan engines of the affected design in the worldwide fleet. The FAA estimates that 193 engines installed on airplanes of U.S. registry would be affected by this proposed AD. The FAA also estimates that it would take approximately one work hour per engine to do the proposed actions, and that the average labor rate is $60 per work hour. Required parts would cost approximately $15,645 per engine. Based on these figures, the total cost of the proposed AD on U.S. operators is estimated to be $3,031,065. CFMI has indicated that this figure may be reduced depending upon warranty agreements.

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 adding the following new airworthiness directive:

CFM International: Docket No. 2001-NE-49-AD.

Applicability

This airworthiness directive (AD) is applicable to CFM International CFM56-5, -5A, and -5B series turbofan engines. These engines are installed on, but not limited to Airbus Industrie A318, A319, A320 and A321 airplanes.

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 (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

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

To prevent unexpected deterioration of critical rotating engine parts due to higher than desired engine operating exhaust gas temperatures (EGT's), do the following:

(a) For affected EGT harnesses and EGT couplings, listed by serial number (SN) in Tables 1, 2, and 3 of CFM International service bulletin (SB) CFM56-5 S/B 77-0020, dated March 4, 2002, for CFM56-5 and -5A series engines, and SB CFM56-5B S/B 77-0008, dated March 4, 2002, for CFM56-5B series engines, do the following:

(1) Replace EGT harnesses and EGT couplings not being trend monitored, with serviceable parts, within 250 hours of operation after the effective date of this AD, or,

(2) After the effective date of this AD, establish an EGT baseline from the installation of the EGT harnesses and coupling, and perform trend monitoring using the System for Analysis of Gas Turbine Engines (SAGE), or equivalent. Replace EGT harnesses and EGT couplings as soon as slow and continuous temperature drift downward (i.e. cooler indication) of 10°C or more from baseline is observed, without a corresponding change in other associated engine parameters such as N1 (LPT rotor speed), N2 (HPT rotor speed), and fuel flow.

Alternative Methods of Compliance

(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 (ECO). Operators must submit their request 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

(c) 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 airplane to a location where the requirements of this AD can be done.

Issued in Burlington, Massachusetts, on June 5, 2002.

Francis A. Favara,

Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service.