In August 2006, we became aware of one report, and in September 2006, two reports of cracking and release of the tripod support legs on the MFP inlet strainer, leading to engine in-flight shutdown, on GE CF34-10E series turbofan engines. When the tripod support legs release, they travel downstream and impact against the MFP gear assembly. This causes the MFP to jam, interrupting fuel flow, which leads to engine flameout. Investigations are ongoing, and our preliminary determination is that the cause of failure is a manufacturing quality control problem with the MFP inlet strainers. Current field data shows that the failures are an infant mortality type of failure. This AD requires removing the low-time strainers first. This condition, if not corrected, could result in an engine in-flight shutdown due to MFP malfunctions.
Relevant Service Information
We have reviewed and approved the technical contents of GE Alert Service Bulletin (ASB) No. CF34-10E S/B 73-A0011, dated September 15, 2006. That ASB describes procedures for removing the MFP inlet strainer, installing a certain replacement flange as an interim repair, and initial and repetitive visual inspections of the main fuel filter.
FAA's Determination and Requirements of This AD
The unsafe condition described previously is likely to exist or develop on other GE CF34-10E series turbofan engines of the same type design. For that reason, we are issuing this AD to prevent engine in- flight shutdown due to MFP malfunctions. This AD requires:
Within 40 engine flight hours after the effective date of this AD, removing the MFP inlet strainer from the affected MFPs listed by serial number in GE ASB No. CF34-10E S/B 73-A0011, dated September 15, 2006; and
Within 150 engine flight hours after the effective date of this AD, removing all other MFP inlet strainers; and
Installing a certain replacement flange in all MFPs as an interim repair; and
Remarking the MFP part number from 2043M12P03 to 2043M12P04; and
Performing initial and repetitive visual inspections of the main fuel filter.
You must use the service information described previously to perform the actions required by this AD.
FAA's Determination of the Effective Date
Since an unsafe condition exists that requires the immediate adoption of this AD, we have found that notice and opportunity for public comment before issuing this AD are impracticable, and that good cause exists for making this amendment effective in less than 30 days.
Interim Action
These actions are interim actions and we may take further rulemaking actions in the future.
Comments Invited
This AD is a final rule that involves requirements affecting flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to send us any written relevant data, views, or arguments regarding this AD. Send your comments to an address listed under ADDRESSES. Include"AD DocketNo. FAA-2006-25896; Directorate Identifier 2006-NE-33-AD" in the subject line of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify it.
We will post all comments we receive, without change, to http://dms.dot.gov , including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this AD. Using the search function of the DMS Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78) or you may visit http://dms.dot.gov .
Examining the AD Docket
You may examine the docket that contains the AD, any comments received, and any final disposition in person at the Docket Management Facility Docket Office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone (800) 647-5227) is located on the plaza level of the Department of Transportation Nassif Building at the street address stated in ADDRESSES. Comments will be available in the AD docket shortly after the DMS receives them.
Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701,"General requirements." Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulationsfor practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.
Regulatory Findings
We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will 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.
For the reasons discussed above, I certify that the 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. 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.
We prepared a summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary at the address listed under ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Under the authority delegated to me by the 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.
Sec. 39.13 [Amended]
2. The FAA amends Sec. 39.13 by adding the following new airworthiness directive: