[Federal Register Volume 63, Number 33 (Thursday, February 19, 1998)] [Proposed Rules] [Pages 8369-8371] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 98-4112] ======================================================================= ----------------------------------------------------------------------- DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. 97-NM-133-AD] RIN 2120-AA64 Airworthiness Directives; Boeing Model 737-100, -200, -300, -400, and -500 Series Airplanes AGENCY: Federal Aviation Administration, DOT. ACTION: Notice of proposed rulemaking (NPRM). ----------------------------------------------------------------------- SUMMARY: This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Boeing Model 737- 100, -200, -300, -400, and -500 series airplanes, that currently requires an inspection of reworked aileron/elevator power control units (PCU's) and rudder PCU's to determine if reworked PCU manifold cylinder bores containing chrome plating are installed, and replacement of the cylinder bores with bores that have been reworked using the oversize method or the steel sleeve method, if necessary. That AD was prompted by a review of the design of the flight control systems on Model 737 series airplanes. The actions specified by that AD are intended to prevent a reduced rate of movement of the elevator, aileron, or rudder due to contamination of hydraulic fluid from chrome plating chips; such reduced rate of movement, if not corrected, could result in reduced controllability of the airplane. This action would expand the applicability of the existing AD to include airplanes equipped with certain rudder PCU's. DATES: Comments must be received by April 6, 1998. ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 97-NM-133-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 Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. FOR FURTHER INFORMATION CONTACT: Don Kurle, Senior Engineer, Systems and Equipment Branch, ANM-130S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2798; fax (425) 227-1181. 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 97-NM-133-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-114, Attention: Rules Docket No. 97-NM-133-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Discussion On April 24, 1997, the FAA issued AD 97-09-14, amendment 39-10010 (62 FR 24008, May 2, 1997), applicable to certain Boeing Model 737-100, -200, -300, -400, and -500 series airplanes, to require an inspection of reworked aileron/elevator power control units (PCU's) and rudder PCU's to determine if reworked PCU manifold cylinder bores containing chrome plating are installed, and replacement of the cylinder bores with bores that have been reworked using the oversize method or the steel sleeve method, if necessary. That action was prompted by a review of the design of the flight control systems on Model 737 series airplanes. The requirements of that AD are intended to prevent a reduced rate of movement of the elevator, aileron, or rudder due to contamination of hydraulic fluid from chrome plating chips; such reduced rate of movement, if not corrected, could result in reduced controllability of the airplane. Actions Since Issuance of Previous Rule Since the issuance of that AD, the manufacturer has requested that the applicability of the existing AD be revised to include airplanes equipped with a rudder power control unit (PCU) having part number 65C37052-( ). The manufacturer points out that AD 94-01-07, amendment 39-8789 (59 FR 4570, February 1, 1994), currently requires certain modifications to the rudder PCU having part number 65-44861. This modification involves replacing the existing dual servo valve in the rudder PCU with an improved servo valve, which revises the existing part number of the rudder PCU to part number 65C37052-( ). However, AD 94-01-07 does not require an inspection of rudder PCU's to determine if reworked PCU manifold cylinder bores containing chrome plating are installed. Upon examination of the request, the FAA finds that Model 737-100, -200, -300, -400, and -500 series airplanes equipped with a rudder PCU having part number 65C37052-( ) are also subject to the addressed unsafe condition of AD 97-09-14 and has included this part number in the applicability of this proposed AD. In addition, the manufacturer pointed out that it erroneously indicated in comments submitted to the notice of proposed rulemaking (NPRM) for AD 97-09-14 that only aileron/elevator actuators having a part number that includes ``ss'' could be eliminated from the applicability of that rule. (Based on these comments, the FAA revised the final rule of that AD accordingly.) However, the ``ss'' is in the serial number, not the part number. The manufacturer also pointed out that it indicated that the ``ss'' only applied to the aileron and elevator PCU's, when it also applies to the rudder PCU's. The FAA has specified this information in the applicability and paragraph (a) of the proposed AD. [[Page 8370]] Explanation of Requirements of Proposed Rule Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would supersede AD 97-09-14 to continue to require an inspection of reworked aileron/elevator power control units (PCU's) and rudder PCU's to determine if reworked PCU manifold cylinder bores containing chrome plating are installed, and replacement of the cylinder bores with bores that have been reworked using the oversize method or the steel sleeve method, if necessary. The proposed AD would expand the applicability of the existing AD to include airplanes equipped with rudder PCU's having part number 65C37052-( ). The proposed AD also revises the existing AD to exclude rudder PCU's (in addition to aileron/elevator actuators) having serial numbers that contain ``ss'' from the requirements of this proposed AD. Cost Impact There are approximately 2,675 Model 737 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 1,091 airplanes of U.S. registry would be affected by this proposed AD. The actions that are currently required by AD 97-09-14, and retained in this proposed AD, take approximately 5 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the currently required actions on U.S. operators is estimated to be $327,300, or $300 per airplane. The new actions that are proposed in this AD action would take approximately 5 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the proposed requirements of this AD on U.S. operators is estimated to be $300 per airplane. The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the current or 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 removing amendment 39-10010 (62 FR 24008, May 2, 1997), and by adding a new airworthiness directive (AD), to read as follows: Boeing: Docket 97-NM-133-AD. Supersedes AD 97-09-14, Amendment 39- 10010. Applicability: Model 737-100, -200, -300, -400, and -500 series airplanes equipped with a rudder power control unit (PCU), having part number (P/N) 65-44861-( ) or P/N 65/C37052-( ) (except those having serial numbers that contain ``ss''), and a serial number less than 1252A; or an aileron or elevator PCU having P/N 65-44761-( ) (except those having serial numbers that contain an ``ss'') and a serial number less than 5360A; certificated in any category. Note 1: This AD applies to each airplane 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 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 (g) 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 a reduced rate of movement of the elevator, aileron, or rudder, which, if not corrected, could result in reduced controllability of the airplane, accomplish the following: Restatement of Requirements of AD 97-09-14, Amendment 39-10010 (a) Perform an inspection of reworked or overhauled aileron and elevator PCU's having P/N 65-44761-( ) (except those having serial numbers that contain an ``ss''), and a serial number less than 5360A; and rudder PCU's having P/N 65-44861-( ) and a serial number less than 1252A (except those having serial numbers that contain ``ss''); to determine if reworked PCU manifold cylinder bores containing chrome plating are installed, in accordance with Boeing Service Letter 737-SL-27-30, dated April 1, 1985. Accomplish the inspection at the earlier of the times specified in paragraphs (a)(1) and (a)(2) of this AD. (1) Within 5 years or 15,000 flight hours after June 6, 1997 (the effective date of AD 97-09-14, amendment 39-10010), whichever occurs first. (2) At the next time the PCU is sent to a repair facility. (b) If any reworked PCU mainfold cylinder bores containing chrome plating are found to be installed during the inspection required by paragraph (a) of this AD: Prior to further flight, replace the cylinder bores with bores that have been reworked using the oversize method or the steel sleeve method specified in Boeing Service Letter 737-SL-27-30, dated April 1, 1985. Accomplish the replacement in accordance with the service letter. (c) As of June 6, 1997, no person shall install a reworked PCU manifold cylinder bore containing chrome plating on an aileron or elevator PCU having P/N 65-44761-( ), or on a rudder PCU having P/N 65-44861-( ), of any airplane unless the cylinder bore has been reworked using the oversize method or the steel sleeve method specified in Boeing Service Letter 737-SL-27-30, dated April 1, 1985. New Requirement of This AD (d) Perform an inspection of reworked or overhauled rudder PCU's having P/N 65C37052-( ) and a serial number less than 1252A (except those having serial numbers that contain ``ss''); to determine if reworked PCU manifold cylinder bores containing chrome plating are installed, in accordance with Boeing Service Letter 737-SL-27-30, dated April 1, 1985. Accomplish the inspection at the earlier of the times specified in paragraphs (d)(1) and (d)(2) of this AD. (1) Within 5 years or 15,000 flight hours after the effective date of this AD, whichever occurs first. [[Page 8371]] (2) At the next time the PCU is sent to a repair facility. (e) If any reworked PCU mainfold cylinder bores containing chrome plating are found to be installed during the inspection required by paragraph (d) of this AD: Prior to further flight, replace the cylinder bores with bores that have been reworked using the oversize method or the steel sleeve method specified in Boeing Service Letter 737-SL-27-30, dated April 1, 1985. Accomplish the replacement in accordance with the service letter. (f) As of the effective date of this AD, no person shall install a reworked PCU manifold cylinder bore containing chrome plating on a rudder PCU having P/N 65C37052-( ), on any airplane unless the cylinder bore has been reworked using the oversize method or the steel sleeve method specified in Boeing Service Letter 737-SL-27-30, dated April 1, 1985. (g) 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, Seattle Aircraft Certification Office (ACO), 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, Seattle ACO. Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. (h) 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 February 11, 1998. Gilbert L. Thompson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 98-4112 Filed 2-18-98; 8:45 am] BILLING CODE 4910-13-U