Airworthiness Directives; CFM International CFM56-2, -2A, -2B, -3, -3B, -3C, -5, -5B, -5C Series Turbofan Engines

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to CFM International (CFMI) CFM56-2, -2A, -2B, -3, -3B, -3C, -5, -5B, -5C series turbofan engines. This proposal would require initial and repetitive visual inspections of the fuel pump filter cover helicoil inserts and bolts for damage, and, if necessary, repair or replacement with serviceable parts. This proposal also would require the installation of new fuel pumps that incorporate an improved filter cover retention design (D-bolts) as terminating action to the inspections. This proposal is prompted by reports that fuel pump filter cover helicoil inserts have loosened or pulled out. The actions specified by the proposed AD are intended to prevent fuel leakage from between the fuel pump filter cover and gear housing, which could result in an engine fire and damage to the airplane.

DATES:

Comments must be received by February 23, 2000.

ADDRESSES:

Submit comments to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 99-NE-40-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may also be sent via the Internet using the following address: “9-ane-adcomment@faa.gov”. Comments sent via the Internet must contain the docket number in the subject line. Comments may be inspected at this location between 8:00 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays.

The service information referenced in the proposed rule may be obtained from CFM International, Technical Publications Department, 1 Neumann Way, Cincinnati, OH 45215; telephone (513) 552-2981, fax (513) 552-2816. This information may be examined 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 (781) 238-7152, fax (781) 238-7199.

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 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 notice 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 notice must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 99-NE-40-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

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-40-AD, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

The Federal Aviation Administration (FAA) has received reports of fuel leakage from between the fuel pump filter cover and gear housing on CFM International (CFMI) CFM56-2, -2A, -2B, -3, -3B, -3C, -5, -5B, -5C series turbofan engines.

Investigation

The investigation revealed that fuel pump filter cover helicoil inserts have loosened or pulled out. The FAA has identified excessive torque during the installation of fuel filter cover bolts as the cause.

Improved Filter Cover

The manufacturer has introduced an improved filter cover retention design using a captured D-bolt and special locking nut that reduces the potential for filter cover bolt over torque damage and loss of bolted joint strength.

Unsafe Condition

This condition, if not corrected, could result in fuel leakage from between the fuel pump filter cover and gear housing, which could result in an engine fire and damage to the airplane.

Service Information

The FAA has reviewed and approved the technical contents of the following CFMI Service Bulletins (SBs), that describe procedures for visual inspections of inserts and bolts for damage, and provide criteria for rejection of hardware and necessary replacement with serviceable parts: CFM56-2 SB 73-110, Revision 2, dated April 29, 1999; CFM56

The FAA has also reviewed and approved the technical contents of the following CFMI SBs, that describe procedures for removal and replacement of fuel pumps (D-bolt fix): CFM56-2 SB 73--A113, dated August 17, 1999; CFM56-2A SB 73-A058, dated August 17, 1999; CFM56-2B SB 73-A079, dated August 17, 1999; CFM56-3/3B/3C SB 73-A129, dated August 17, 1999; CFM56-5 SB 73-A143, dated June 18, 1999; CFM56-5B SB 73-A062, dated June 18, 1999; CFM56-5C SB 73-A078, dated June 21, 1999.

Differences Between Service Bulletins and This AD

The referenced SBs describe a one-time inspection. This AD requires repetitive inspections at every filter change.

Proposed Inspections and Repair or Replacement

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 require initial and repetitive visual inspections of helicoil inserts and bolts for damage defined in the applicable SBs. The inspections would be required at each fuel filter replacement. If the damage equals or exceeds the reject criteria, this AD would require, prior to further flight, removing the damaged hardware from service and replacement with serviceable parts, or repairing the damaged hardware.

Terminating Action

This AD would also require the installation of new fuel pumps that incorporate an improved filter cover retention design (D-bolts) as a terminating action to the inspections. The actions would be required to be accomplished in accordance with the SBs described previously.

Economic Analysis

There are approximately 8,781 engines of the affected design in the worldwide fleet. The FAA estimates that 4,063 engines installed on aircraft of U.S. registry would be affected by this proposed AD, that it would take approximately 0.3 work hours per engine to accomplish the proposed inspections and 3 work hours per engine to accomplish the proposed D-bolt installation, and that the average labor rate is $60 per work hour. The FAA therefore estimates the total cost to US operators of this proposed rule is $73,134 for one inspection and $4,958,658 for hardware/D-bolt installation.

Regulatory Impact

This proposal 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 proposal.

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.