03-12241. Airworthiness Directives; CFM International, S.A. CFM56-2C, -3 Series, and -5 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, S.A. CFM56-2C, -3, and -5 series turbofan engines. This proposal would require removing from service main fuel pumps with bronze bearings and installing main fuel pumps with aluminum/bronze alloy bearings. This proposal is prompted by several reports of indications of wear and failures of main fuel pump bronze bearings. The actions specified by the proposed AD are intended to prevent failures of main fuel pump bearings, resulting in fuel filter clogging, fuel flow degradation, fuel manifold and nozzle clogging resulting in diminished in-flight restart capability, low pressure turbine (LPT) case burn-through, inability to obtain a successful engine start, and damage to the airplane.

DATES:

Comments must be received by July 15, 2003.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2002-NE-26-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.

FOR FURTHER INFORMATION CONTACT:

Glorianne Niebuhr, 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 2002-NE-26-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. 2002-NE-26-AD, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

The FAA has become aware that since the introduction of main fuel pump bronze bearings into service on CFM56-2C, -3, and -5 series turbofan engines, wear of the backside of the bearings into the main fuel bearing plate has been observed. This can lead to fuel filter clogging, fuel flow degradation, fuel manifold and nozzle clogging resulting in diminished in-flight restart capability, LPT case burn-through, inability to obtain a successful engine start, and damage to the airplane. The main fuel pump manufacturer has determined that this wear is caused by the low coefficient of friction between the bronze bearings and the aluminum bearing plate which allowed relative movement of the bearing during operation. The main fuel pump manufacturer has shown that main fuel pumps with aluminum/bronze alloy bearings have a high coefficient of friction between the bearing and the aluminum bearing plate minimizing relative movement of the bearings and reducing wear. Use of main fuel pumps with aluminum/bronze alloy bearings decreases the risk of bearing failure which could lead to fuel filter clogging, fuel flow degradation, fuel manifold and nozzle clogging resulting in diminished in-flight restart capability, LPT case burn-through, inability to obtain a successful engine start, and damage to the airplane.

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, S.A. CFM56-2C, -3 series, and -5 series turbofan engines of the same type design, the proposed AD would require removal from service of certain part number main fuel pumps and installation of serviceable main fuel pumps. The actions would be required to be done at the next engine removal, engine module removal, or main fuel pump removal after the effective date of this AD, whichever is earlier, but no later than January 1, 2007.

Economic Analysis

There are approximately 6,048 CFM56-2C, -3 series, and -5 series turbofan engines of the affected design in the worldwide fleet. The FAA estimates that 2,249 engines installed on airplanes of U.S. registry would be affected by this proposed AD. A replacement fuel pump would cost approximately $74,000. Using average shop visitation rates, 562 engines are expected to be affected per year. Based on these figures, the total cost to replace fuel pumps for U.S. operators is estimated to be $41,588,000 per year.

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, S.A.: Docket No. 2002-NE-26-AD.

Applicability: This airworthiness directive (AD) is applicable to CFM International, S.A. CFM56-2C, -3, and -5 series turbofan engines. These engines are installed on, but not limited to Airbus Industrie A319, A320, Boeing 737, and McDonnell Douglas DC-8 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 (e) 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 at the next engine removal, engine module removal, or main fuel pump removal after the effective date of this AD, whichever is earlier, but no later than January 1, 2007, unless already done.

To prevent failures of main fuel pump bearings, resulting in fuel filter clogging, fuel flow degradation, fuel manifold and nozzle clogging resulting in diminished in-flight restart capability, low pressure turbine (LPT) case burn-through, inability to obtain a successful engine start, and damage to the airplane, do the following:

Main Fuel Pumps Installed on CFM56-2C Engines

(a) For CFM56-2C engines, do the following:

(1) Remove from service main fuel pumps part number (P/N) 301-779-002-0.

(2) For all CFM56-2C series engines that have incorporated CFM International (CFMI) Service Bulletin (SB) (CFM56-2C) 73-081, remove from service main fuel pumps P/N 301-776-101-0, P/N 301-776-102-0, P/N 301-776-103-0, P/N 301-776-104-0, P/N 301-776-105-0, P/N 301-776-106-0, P/N 301-776-108-0, P/N 301-776-109-0, P/N 301-776-110-0, P/N 301-776-111-0, P/N 301-776-112-0, P/N 301-776-113-0, P/N 301-778-801-0, P/N 301-778-802-0, P/N 301-778-804-0, and P/N 301-778-805-0.

(3) For all CFM56-2C engines that have incorporated CFMI SB (CFM56-2C) 73-078, remove from service main fuel pumps P/N 301-779-006-0.

(4) Install a serviceable main fuel pump. Information on converting removed pumps into serviceable pumps can be found in CFMI SB (CFM56-2C) 73-0104, Revision 2, dated July 27, 2000.

Main Fuel Pumps Installed on CFM56-3 Series Engines

(b) For CFM56-3 series engines, do the following:

(1) Remove main fuel pumps P/N 301-779-002-0.

(2) For all CFM56-3 series engines that have incorporated CFMI SB (CFM56-3) 73-082, remove from service main fuel pumps P/N 301-779-006-0.

(3) For all CFM56-3 series engines that have incorporated CFMI SB (CFM56-3) 73-087, remove from service main fuel pumps P/N 301-778-801-0, P/N 301-778-802-0, P/N 301-778-804-0, and P/N 301-778-805-0.

(4) Install a serviceable main fuel pump. Information on converting removed pumps into serviceable pumps can be found in CFMI SB (CFM56-3) 73-0120, Revision 4, dated July 27, 2000.

Main Fuel Pumps Installed on CFM56-5 Series Engines

(c) For CFM56-5 series engines, do the following:

(1) Remove main fuel pumps P/N 301-785-502-0.

(2) For all CFM56-5 series engines that have incorporated CFMI SB (CFM56-5A) 73-077, remove from service main fuel pumps P/N 301-785-504-0.

(3) Install a serviceable main fuel pump. Information on converting removed pumps into serviceable pumps can be found in CFMI SB (CFM56-5A) 73-0126, Revision 3, dated September 25, 2000.

Do Not Install Main Fuel Pumps

(d) After the effective date of this AD, do not install the following P/N main fuel pumps onto any engine:

(1) For all engines: (P/N) 301-779-002-0, P/N 301-779-006-0, P/N 301-785-502-0, and P/N 301-785-504-0.

(2) For CFM56-2C engines that have incorporated SB CFMI (CFM56-2C) 73-081 but have not incorporated SB CFMI SB (CFM56-2C) 73-0104: P/N 301-776-101-0, P/N 301-776-102-0, P/N 301-776-103-0, P/N 301-776-104-0, P/N 301-776-105-0, P/N 301-776-106-0, P/N 301-776-108-0, P/N 301-776-109-0, P/N 301-776-110-0, P/N 301-776-111-0, P/N 301-776-112-0, P/N 301-776-113-0, P/N 301-778-801-0, P/N 301-778-802-0, P/N 301-778-804-0, P/N 301-778-805-0.

(3) For CFM56-3 series engines that have incorporated SB CFMI (CFM56-3) 73-087 but have not incorporated CFMI SB (CFM56-3) 73-0120: P/N 301-778-801-0, P/N 301-778-802-0, P/N 301-778-804-0, and P/N 301-778-805-0.

Alternative Methods of Compliance

(e) 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

(f) 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 May 12, 2003.

Francis A. Favara,

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