Events Leading to Issuance of the Proposed AD
The Civil Airworthiness Authority (CAA), which is the airworthiness authority for the United Kingdom, recently notified the FAA that an unsafe condition may exist on certain FLS Aerospace (Lovaux) Ltd. OA7 Optica series 300 airplanes equipped with a Hoffman fan, part number (P/N) HO-E315/122EZ, and fan shaft extension. The CAA for the United Kingdom reports that a manufacturing process error could cause structural failure of the fan shaft extension.
This extension is attached to the engine propeller flange by six bolts. Of the six bushes on the propeller flange, four require a counterbore in the extension propeller flange. A quality control review of the manufacturing process has revealed that the depth of these counterbores on certain OA7 Optica 300 series airplanes equipped with a Hoffman fan, part number P/N HO-E315/122EZ, and fan shaft extension exceed 4.5 millimeters (mm). This could result in cracks forming in the propeller flange with subsequent structural failure of the fan shaft extension.
Applicable Service Information
FLS Aerospace Lovaux Mandatory Service Bulletin (MSB) No. B2/MSB/006, Issue: 1, dated August 22, 1994, specifies the following:
- measuring the depth of the four counterbores on the fan shaft extension to the engine attachment flange;
- inspecting the counterbores and propeller flange for cracks;
- incorporating Repair Drawing R 1299; and
- incorporating Modification B2/MOD/047 on the fan shaft extension.
The CAA of the United Kingdom classified this service bulletin as mandatory and issued CAA AD 010-08-94, in order to assure the continued airworthiness of these airplanes in the United Kingdom.
The FAA's Determination
This airplane model is manufactured in the United Kingdom and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.19) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the CAA of the United Kingdom has kept the FAA informed of the situation described above. The FAA has examined the findings of the CAA of the United Kingdom; reviewed all available information, including the service information and modification referenced above; and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.
Explanation of the Provisions of This AD
Since an unsafe condition has been identified that is likely to exist or develop on other FLS Aerospace (Lovaux) Ltd. OA7 Optica series 300 airplanes of the same type design registered in the United States equipped with a Hoffman fan, P/N HO-E315/122EZ, and fan shaft extension, the FAA is issuing an AD. This AD requires replacing the fan shaft extension with one that incorporates Modification No. B2/MOD/047. Accomplishment of the modification would be in accordance with FL Aerospace Lovaux Modification Leaflet No. B2/MOD/047, dated August 31, 1994.
Differences Between This AD, Service Information, and the CAA AD
Both FLS Aerospace Lovaux Mandatory Service Bulletin (MSB) No. B2/MSB/006, Issue: 1, dated August 22, 1994, and CAA AD 010-08-94 specify the following:
- AT 50 HOURS TIME-IN-SERVICE (TIS): inspecting the fan shaft extension to engine attachment flange for cracks and replacing the fan shaft extension if any cracks are found; and measuring the depth of the four counterbores on the fan shaft extension to engine attachment flange incorporating Repair Drawing R 1299 if counterbores exceed a certain depth;
- AT 200 HOURS TIS: incorporating Modification B2/MOD/047 on the fan shaft extension.
Accomplishing the inspection, measurement, and possible repair allow the airplane to be operated until a Modification B2/MOD/047 fan shaft extension is installed. This AD only requires replacing the fan shaft extension. Since no airplanes are currently on the U.S. Register, the FAA has determined to require immediate fan shaft extension replacement on any aircraft obtaining a U.S. airworthiness certificate rather than require the inspection, measurement, and possible repair, and then require the replacement.
Cost Impact
None of the FLS Aerospace (Lovaux) Ltd. OA7 Optica series 300 airplanes affected by this action are on the U.S. Register. All airplanes included in the applicability of this rule currently are operated by non-U.S. operators under foreign registry; therefore, they are not directly affected by this AD action. However, the FAA considers this rule necessary to ensure that the unsafe condition is addressed in the event that any of these subject airplanes are imported and placed on the U.S. Register.
Should an affected airplane be imported and placed on the U.S. Register, accomplishment of the required replacement would take approximately 4 workhours at an average labor charge of $60 per workhour. Parts cost approximately $300 per airplane. Based on these figures, the total cost impact of this AD would be $540 per airplane that would become registered in the United States.
The Effective Date of This AD
Since this AD action does not affect any airplane that is currently on the U.S. register, it has no adverse economic impact and imposes no additional burden on any person. Therefore, notice and public procedures hereon are unnecessary and the amendment may be made effective in less than 30 days after publication in the Federal Register.
Comments Invited
Although this action is in the form of a final rule and was not preceded by notice and 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 shall 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 rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket No. 96-CE-12-AD." The postcard will be date stamped and returned to the commenter.
Regulatory Impact
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.
For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under 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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it 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 part 39 continues to read as follows:
Authority: 49 USC 106(g), 40113, 44701.
39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive (AD) to read as follows: