[Federal Register Volume 61, Number 161 (Monday, August 19, 1996)] [Proposed Rules] [Pages 42825-42826] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 96-21010] ======================================================================= ----------------------------------------------------------------------- DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. 96-NM-140-AD] RIN 2120-AA64 Airworthiness Directives; Aerospatiale Model ATR72 Series Airplanes AGENCY: Federal Aviation Administration, DOT. ACTION: Notice of proposed rulemaking (NPRM). ----------------------------------------------------------------------- SUMMARY: This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Aerospatiale Model ATR72 series airplanes. This proposal would require modification of the pitch uncoupling mechanism of both elevators. This proposal is prompted by reports of fatigue cracking of the pitch uncoupling mechanism and the torque tube of the elevator. Failure of the pitch uncoupling mechanism due to fatigue cracking could result in the uncommanded uncoupling of the elevators. The actions specified by the proposed AD are intended to prevent such fatigue cracking and subsequent uncommanded uncoupling of the elevators, which could result in reduced controllability of the airplane. DATES: Comments must be received by September 27, 1996. ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 96-NM-140-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays. The service information referenced in the proposed rule may be obtained from Aerospatiale, 316 Route de Bayonne, 31060 Toulouse, Cedex 03, France. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. FOR FURTHER INFORMATION CONTACT: Gary Lium, Aerospace Engineer, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 227-1112; fax (206) 227-1149. SUPPLEMENTARY INFORMATION: Comments Invited Interested persons are invited to participate in the making of the proposed 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 above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received. Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with the substance of this proposal 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 96-NM-140-AD.'' The postcard will be date stamped and returned to the commenter. Availability of NPRMs Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 96-NM-140-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Discussion The Direction Generale de l'Aviation Civile (DGAC), which is the airworthiness authority for France recently notified the FAA that an unsafe condition may exist on certain Aerospatiale Model ATR72 series airplanes. The DGAC advises that it has received reports indicating that fatigue cracks have been found at the junction of the center section of the pitch uncoupling mechanism of the elevators, and the torque tube that connects the operation of both elevators. Such fatigue cracking could cause failure of the elevator coupling mechanism, and result in the uncommanded uncoupling of the elevators. This condition, if not detected and corrected in a timely manner, could result in reduced controllability of the airplane. Explanation of Relevant Service Information Avions de Transport Regional (ATR) has issued Service Bulletin ATR72-27-1044, dated March 5, 1996, which describes procedures for modifying the pitch uncoupling mechanism of the elevators. Among other actions, the modification involves replacing the aluminum flanges of the pitch uncoupling mechanism with steel flanges, and reidentifying the uncoupling mechanism with a new part number after modification. The replacement will prevent fatigue cracking of the pitch uncoupling mechanism and the torque tube of the elevators. The DGAC classified this service bulletin as mandatory and issued French airworthiness directive (CN) 96-019-028(B), dated January 17, 1996, in order to assure the continued airworthiness of these airplanes in France. FAA's Conclusions This airplane model is manufactured in France 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 DGAC has kept the FAA informed of the situation described above. The FAA has examined the findings of the DGAC, 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. Explanation of Requirements of Proposed Rule Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, the proposed AD would require modification of the elevator uncoupling mechanism. This action would be required to be accomplished in accordance with the service bulletin described previously. Cost Impact The FAA estimates that 51 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 55 work hours per airplane to accomplish the proposed [[Page 42826]] actions, and that the average labor rate is $60 per work hour. The required parts would be provided by the manufacturer at not cost to the operator. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $168,300, or $3,300 per airplane. The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. Regulatory Impact The regulations proposed herein would 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 proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. For the reasons discussed above, I certify that this proposed 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) if promulgated, 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 copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting 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. The Proposed Amendment Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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: Aerospatiale: Docket 96-NM-140-AD. Applicability: Model ATR72-101, -102, -201, -202, -211, and -212 series airplanes on which Modification 4495 or Aerospatiale Service Bulletin ATR 72-27-1044 has not been accomplished; certificated in any category. Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes 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 uncoupling of the elevators due to failure of the elevator coupling mechanism and resultant reduced controllability of the airplane, accomplish the following: (a) Prior to the accumulation of 12,000 total landings, or within 1,000 landings after the effective date of this AD, whichever occurs later: Modify the elevator uncoupling mechanism in accordance with Aerospatiale Service Bulletin ATR72-27-1044, dated March 5, 1996. (b) As of the effective date of this AD, no person shall install a pitch uncoupling mechanism of the elevator, having the following part numbers, on any airplane: S2738194100800 S2738194102895 S2738194102200 S2738194102400 S2738194102800 S2738194103200 (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, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Standardization Branch, ANM-113. Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Standardization Branch, ANM-113. (d) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. Issued in Renton, Washington, on August 12, 1996. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 96-21010 Filed 8-16-96; 8:45 am] BILLING CODE 4910-13-U