The FAA has been informed by CFMI that the cyclic life limit of the CFM56-5C4/1 Low Pressure Turbine (LPT) conical support, P/N 337-002-407-0, published in the Time Limits Section of Chapter 5 of the CFM56-5C Engine Shop Manual is incorrect, and will be corrected at the next revision to the manual. The incorrect published cyclic life reads 15,000 cycles since new (CSN) instead of the certified value of 9,350 CSN. This condition, if not corrected, could result in the LPT conical support remaining in service beyond its certified cyclic life limit, which could result in an uncontained engine failure and damage to the airplane. Currently, the CFMI fleet has not incorporated LPT Conical Support, P/N 337-002-407-0, into any of the CFM56-5C4/1 engines. Therefore, this AD will not result in any economic impact on the U.S. operators. However, as the operators convert CMF56-5C engines into different model configurations, there is a potential that LPT Conical Support, P/N 337-002-407-0, will be installed in the CFM56-5C4/1 engine model.
FAA's Determination of An Unsafe Condition and Proposed Actions
Although this affected engine model is not used on any airplanes that are registered in the United States, the possibility exists this engine model could be used on airplanes that are registered in the United States in the future. This AD reestablishes the certified cyclic life limit for LPT conical support P/N 337-002-407-0, by requiring the replacement of LPT conical support P/N 337-002-407-0, at or before accumulating 9,350 CSN. This AD is being issued to prevent LPT conical supports from remaining in service beyond their certified cyclic life limit, which could result in an uncontained engine failure and damage to the airplane.
Immediate Adoption of This AD
Since there are no domestic operators of this engine model, notice and opportunity for prior public comment are unnecessary. Therefore, a situation exists that allows the immediate adoption of this regulation.
Comments Invited
Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.
Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the 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 that summarizes each FAA-public contact concerned with the substance of this AD 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-15-AD." The postcard will be date stamped and returned to the commenter.
Regulatory Impact
This final 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 final rule.
The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from 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.
Adoption of the Amendment
Accordingly, pursuant to 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. Section 39.13 is amended by adding the following new airworthiness directive: