Airworthiness directives: General Electric Co.,
[Federal Register: March 9, 2000 (Volume 65, Number 47)]
[Rules and Regulations]
[Page 12460-12462]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr09mr00-5]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2000-NE-06-AD; Amendment 39-11619; AD 2000-05-10]
RIN 2120-AA64
Airworthiness Directives; General Electric Company GE90-85B Series Turbofan Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
SUMMARY: This amendment adopts a new airworthiness directive (AD) that is applicable to General Electric Company GE90-85B series turbofan engines. This action requires removing from service aft mount whiffletrees prior to reaching a new cyclic life limit, and replacing with serviceable parts. This amendment is prompted by a reassessment of the low cycle fatigue capability of the engine mount system due to an increase in engine and propulsion system weight. The actions specified in this AD are intended to prevent aft mount
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whiffletree failure, which if it occurred with other critical aft mount component failures, could possibly result in an engine mount system failure, and separation of the engine from the aircraft.
DATES: Effective April 7, 2000.
Comments for inclusion in the Rules Docket must be received on or before May 8, 2000.
ADDRESSES: Submit comments to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2000-NE-06-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.
FOR FURTHER INFORMATION CONTACT: John E. Golinski, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone 781- 238-7135, fax 781-238-7199.
SUPPLEMENTARY INFORMATION: General Electric Company (GE), the manufacturer of GE90-85B series turbofan engines, has recently reassessed the low cycle fatigue (LCF) capability of the engine mount system due to an increase in engine and propulsion system weight. The analysis indicates a reduction in the LCF life for aft mount whiffletree, part number (P/N) 1692M12G02. Prior to completing the assessment for the engine weight and propulsion system weight increase, there was no life limit for the aft mount whiffletree, P/N 1692M12G02, in Chapter 5, Airworthiness Limitations Section, of the Engine Manual for GE90-85B engines because the calculated LCF life value was greater than the aircraft life. Chapter 5 has now been revised to include a new life limit for the aft mount whiffletree, P/N1692M12G02, of 18,000 cycles-since-new (CSN). An aft mount whiffletree failure, which if it occurred with other critical aft mount component failures, could possibly result in an engine mount system failure, and separation of the engine from the aircraft.
New Components
GE has developed improved aft mount whiffletrees that are eligible for installation on all GE90 engine models and do not have a life limit. The majority of GE90 engines in revenue service incorporate one of these improved wiffletrees.
No Domestic Engines
The FAA estimates that there are only 3 engines in revenue service that contain the aft mount whiffletree, P/N 1692M12G02, and that none of these are installed on aircraft of US registry.
Required Actions
Since an unsafe condition has been identified that is likely to exist or develop on other engines of the same type design, this AD is being issued to prevent aft mount whiffletree failure. This AD requires removing from service aft mount whiffletrees prior to accumulating 18,000 CSN, and replacing with serviceable parts.
Immediate Adoption
There are currently no domestic operators of this engine model with the affected component installed. Accordingly, a situation exists that allows the immediate adoption of this regulation. Notice and opportunity for prior public comment hereon are impracticable, and good cause exists for making this amendment effective in less than 30 days.
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 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 filedin 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 2000-NE-06-AD.'' The postcard will be date stamped and returned to the commenter.
Regulatory Impact
The regulations adopted herein 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. Therefore, it is determined that this final rule does not have federalism implications under Executive Order (EO) No. 13132.
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 EO No. 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
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The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
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Section 39.13 is amended by adding the following new airworthiness directive:
2000-05-10 General Electric Company: Amendment 39-11619. Docket 2000-NE-06-AD.
Applicability: General Electric Company (GE) GE90-85B series turbofan engines, with aft mount whiffletrees, part number (P/N) 1692M12G02, installed. These engines are installed on but not limited to Boeing 777 series airplanes.
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Note 1: This airworthiness directive (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 (c) 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: Required as indicated, unless accomplished previously.
To prevent aft mount whiffletree failure, which if it occurred with other critical aft mount component failures, could possibly result in an engine mount system failure, and separation of the engine from the aircraft, accomplish the following:
New Life Limit
(a) Remove from service aft mount whiffletrees, P/N 1692M12G02, before accumulating 18,000 cycles-since-new, and replace with serviceable parts.
(b) Except for the provisions of paragraph (c) of this AD, no aft mount whiffletrees, P/N 1692M12G02, may remain in service beyond the new life limit stated in paragraph (a) of this AD.
Alternative Methods of Compliance
(c) 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 shall submit their requests 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.
(d) This amendment becomes effective on April 7, 2000.
Issued in Burlington, Massachusetts, on March 1, 2000. Diane S. Romanosky, Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service.
[FR Doc. 00-5582Filed3-8-00; 8:45 am]
BILLING CODE 4910-13-U
