Airworthiness directives: Boeing,

[Federal Register: April 26, 1999 (Volume 64, Number 79)]

[Proposed Rules]

[Page 20226-20229]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr26ap99-35]

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: Supplemental notice of proposed rulemaking; reopening of comment period.

SUMMARY: This document revises an earlier proposed airworthiness directive (AD), which would have superseded an existing AD that is applicable to certain Boeing Model 737-100, -200, -300, -400, and -500 series airplanes. The existing AD 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. This action, among other items, revises the previously proposed rule by expanding the applicability of the existing AD to include airplanes equipped with certain rudder PCU's. The actions specified by this new proposed 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.

DATES: Comments must be received by May 21, 1999.

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 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

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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

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to add an airworthiness directive (AD), applicable to certain Boeing Model 737-100, -200, -300, -400, and -500 series airplanes, was published as a notice of proposed rulemaking (NPRM) in the Federal Register on February 19, 1998 (63 FR 8369). That NPRM would have superseded AD 97-09-14, amendment 39-10010 (62 FR 24008, May 2, 1997), 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. That NPRM would have expanded the applicability of the existing AD to include airplanes equipped with rudder PCU's having part number (P/N) 65C37052-(). That NPRM also would have revised the existing AD to exclude rudder PCU's (in addition to aileron/elevator actuators) having serial numbers that contain ``ss'' from the requirements of the proposed AD. That NPRM was prompted by a review of the design of the flight control systems on Model 737 series airplanes. The actions specified in that NPRM were 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 Proposal

Due consideration has been given to the comments received in response to the NPRM.

Two commenters support the proposed rule.

Requests To Add a Certain Rudder PCU to the Requirements of the Proposed AD

Several commenters state that rudder PCU's having P/N 65C37053-( ) are subject to the identified unsafe condition, and therefore, should be included in the applicability statement and paragraphs (d) and (f) of the proposed AD. The commenters note that AD 97-14-04, amendment 39- 10061 (62 FR 35068, June 30, 1997), requires replacement of rudder PCU's having P/N 65C37052-( ) with PCU's having P/N 65C37053-( ). The commenters point out that PCU's having P/N 65C37053-( ) are upgraded from the same base PCU as the PCU's having P/N 65C37052-( ). The FAA concurs. The FAA inadvertently omitted PCU, P/N 65C37053-( ), from the requirements of the proposed AD. Therefore, the FAA has revised the applicability statement and paragraphs (d) and (f) of the supplemental NPRM accordingly.

Request To Allow Replacement With New Manifolds

One commenter requests that the FAA revise paragraphs (b) and (e) of the proposed AD to allow PCU manifolds containing chrome plated cylinder bores to be replaced with new manifolds, in addition to bores that have been reworked using the oversize method or the steel method. The commenter states that the original equipment manufacturer has not produced PCU manifolds with chrome plated cylinder bores since 1985. The FAA concurs. The FAA has confirmed with Boeing that manifolds with chrome plated bores have not been produced since 1985. Therefore, the FAA has revised the requirements of paragraphs (b) and (e) of the supplemental NPRM to include an option of replacing the cylinder bores containing chrome plating with PCU manifold cylinder bores that were manufactured after December 31, 1985, in lieu of replacing the cylinder bores that have been reworked using the oversize method or steel sleeve method. In addition, the proposed requirements of those paragraphs have been revised to allow operators to replace the rudder, aileron, or elevator PCU with a certain PCU, as applicable.

Request To Delete Reference to Incorrect Service Letter

One commenter requests that the sentence ``accomplish the replacement in accordance with the service letter'' be deleted from paragraphs (b) and (e) of the proposed AD. The commenter states the Boeing Service Letter 737-SL-27-30, dated April 1, 1985, does not contain any replacement instructions. The commenter contends that the service letter recommends the removal of the chrome bores and advises of alternative repair methods.

The FAA concurs partially. The FAA acknowledges that the subject service letter does not contain replacement procedures for accomplishment of the requirements of paragraphs (b) and (e) of the AD. The FAA has consulted with Boeing and determined that the following chapters of the Boeing 737 Airplane Maintenance Manual (AMM) contain the appropriate procedures for accomplishment of the actions specified in paragraphs (b) and (e) of this AD:

‹bullet› Chapter 27-11-71 (for Model 737-100, -200, -300, -400, and -500 series airplanes) for replacement of the aileron PCU;

‹bullet› Chapter 27-31-101 (for Model 737-100 and -200 series airplanes), and Chapter 27-31-14 (for Model 737-300, -400, and -500 series airplanes) for replacement of the elevator PCU; and

‹bullet› Chapter 27-21-91 (for Model 737-100, -200, -300, -400, and -500 series airplanes) for replacement of the rudder PCU.

Therefore, the FAA has revised paragraphs (b) and (e) of the supplemental NPRM to reference these chapters of the AMM as the appropriate sources of service information for accomplishment of the actions specified in paragraphs (b)(1), (b)(2), (b)(3), (e)(1), and (e)(2), as applicable.

Requests To Accept Previously Approved Alternative Method of Compliance (AMOC)

Two commenters request that the inspection method specified in Boeing Service Letter 737-SL-27-120, dated January 28, 1998, be considered acceptable for compliance with the inspection requirements of paragraphs (a) and (d) of the proposed AD. One of these commenters states that the FAA approved this inspection method as an AMOC in accordance with AD 97-09-14. The other commenter states that the subject inspection method can be accomplished without removing the PCU's from the airplanes and disassembling them. The FAA concurs with the commenters' request. The FAA has added a new paragraph (g)(2) to the supplemental NPRM to include a statement that reflects this point.

Conclusion

Since some of these changes expand the scope of the originally proposed rule, the FAA has determined that it is necessary to reopen the comment period to provide additional opportunity for public comment.

Cost Impact

There are approximately 2,675 Model 737 series airplanes of the affected design in the worldwide fleet. The FAA

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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 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, certificated in any category; equipped with the following power control units (PCU):

   ‹bullet› a rudder PCU, having part number (P/N) 65-44861-( ), P/ N 65C37052-( ), or P/N 65C37053-( ) (except those having serial numbers that contain ``ss''), and a serial number less than 1252A; or

   ‹bullet› 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.

   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)(1) 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:

   (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 manifold cylinder bores containing chrome plating are found to be installed during the inspection required by paragraph (a) of this AD: Prior to further flight, accomplish the actions specified in paragraph (b)(1), (b)(2), or (b)(3) of this AD in accordance with Chapter 27-11-71 (for Model 737-100, -200, -300, -400, and -500 series airplanes), Chapter 27- 31-101 (for Model 737-100 and -200 series airplanes), or Chapter 27- 31-14 (for Model 737-300, -400, and -500 series airplanes) of Boeing 737 Airplane Maintenance Manual (AMM); as applicable.

   (1) Replace the cylinder bores with bores that were manufactured after December 31, 1985, or 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.

   (2) Replace the aileron or elevator PCU with a PCU containing the letters ``ss'' in its serial number or with a PCU having a serial number of 5306A or higher.

   (3) Replace the rudder PCU with a PCU containing the letters ``ss'' in its serial number or with a PCU having a serial number of 1252A or higher.

   (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-( ), 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.

   (d) Perform an inspection of reworked or overhauled rudder PCU's having P/N 65C37052-( ) or P/N 65C37053-( ) 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.

   (2) At the next time the PCU is sent to a repair facility.

   (e) If any reworked PCU manifold cylinder bores containing chrome plating are found to be installed during the inspection required by paragraph (d) of this AD: Prior to further flight, accomplish the actions specified in paragraph (e)(1) or (e)(2) of this AD in accordance with Chapter 27-21-91 (for Model 737-100, - 200, -300, -400, and -500 series airplanes) of Boeing 737 Airplane Maintenance Manual (AMM).

   (1) Replace the cylinder bores with bores that were manufactured after December 31, 1985, or 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.

   (2) Replace the rudder PCU with a PCU containing the letters ``ss'' in its serial

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   number or with a PCU having a serial number of 1252A or higher.

   (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-( ) or P/N 65C37053-( ) 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)(1) 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.

   (g)(2) Alternative methods of compliance, approved previously in accordance with AD 97-09-14, amendment 39-10010, are approved as alternative methods of compliance with this AD.

   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 April 20, 1999. D.L. Riggin, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

   [FR Doc. 99-10346Filed4-23-99; 8:45 am]

   BILLING CODE 4910-13-P