The Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom (UK), recently notified the Federal Aviation Administration (FAA) that an unsafe condition may exist on Rolls-Royce Limited (R-R), Aero Division-Bristol, S.N.E.C.M.A., Olympus 593 Mk. 610-14-28 turbojet engines. The CAA advises that they have received reports of circumferential cracks at the No. 2 outer and inner rings of the combustor chamber, resulting in a section of the combustion chamber detaching and causing significant ignitor and low pressure turbine damage. The investigation revealed that the length of the web is under minimum drawing dimension, resulting in inadequate weld penetration, causing cracks to initiate and propagate along the weld joint. There are currently no affected engines operated on aircraft of U.S. registry. This AD, then, is necessary to require accomplishment of the required actions for engines installed on aircraft currently of foreign registry that may someday be imported into the US or aircraft that are currently operated in the U.S. Accordingly, the FAA has determined that notice and prior opportunity for comment are unnecessary and good cause exists for making this amendment effective in less than 30 days. This condition, if not corrected, could result in combustion chamber detachment, which could result in an inflight engine shutdown or an engine fire.
R-R has issued Service Bulletin (SB) No. OL.593-72-9038-417, dated June 26, 1996, that specifies procedures for a radiological inspection of the combustion chamber No. 2 outer cooling ring scoop circumferential and axial weld for weld quality, and reweld and reinspection, if necessary; and SB No. OL.593-72-9048-424, dated April 25, 1997, that specifies procedures for an inspection of the combustion chamber No. 2 inner and outer cooling ring web length, marking acceptable components with the letter "T" adjacent to the part number, and replacement of unacceptable components with serviceable parts. The CAA classified these SBs as mandatory and issued ADs 008-06-96 and 004-04-97 in order to assure the airworthiness of these engines in the UK.
This engine model is manufactured in the UK and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the CAA has kept the FAA informed of the situation described above. The FAA has examined the findings of the CAA, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.
Since an unsafe condition has been identified that is likely to exist or develop on other engines of the same type design registered in the United States, this AD requires, at the next combustor exposure after the effective date of this AD, a radiological inspection of the combustion chamber No. 2 outer cooling ring scoop circumferential and axial weld for weld quality, and reweld and reinspection, if necessary; and an inspection of the combustion chamber No. 2 inner and outer cooling ring web length, marking acceptable components with the letter "T" adjacent to the part number, and replacement of unacceptable components with serviceable parts. The actions would be required to be accomplished in accordance with the SBs described previously.
Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that 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 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 reportthat 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 notice must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 98-ANE-12-AD." The postcard will be date stamped and returned to the commenter.
The regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.
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, Incorporation by reference, 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 part39 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: