Airworthiness directives: Boeing,
[Federal Register: December 22, 2003 (Volume 68, Number 245)]
[Proposed Rules]
[Page 71047-71049]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr22de03-12]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
[Docket No. 2003-NM-89-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 757 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 all Boeing Model 757 series airplanes. For certain affected airplanes, this proposal would require repetitive testing of the secondary brakes of the horizontal stabilizer trim actuator (HSTA). For all affected airplanes, this proposal would require repetitive overhauls of the primary brake, ballscrew assembly, and differential assembly of the HSTA, which would constitute terminating action for the repetitive testing of the secondary brake. This action is necessary to prevent grease contamination on the primary HSTA brake and consequent loss of the primary brake function, which, in combination with the loss of the secondary HSTA brake function, could result in loss of control of the airplane. This action is intended to address the identified unsafe condition.
DATES: Comments must be received by February 5, 2004.
ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-89-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to (425) 227-1232. Comments may also be sent via the Internet using the following address: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must contain ``Docket No. 2003-NM-89-AD'' in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 or 2000 or ASCII text.
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: Kenneth W. Frey, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington; telephone (425) 917-6468; fax (425) 917-6590.
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 action may be changed in light of the comments received.
Submit comments using the following format:
[sbull] Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
[sbull] For each issue, state what specific change to the proposed AD is being requested.
[sbull] Include justification (e.g., reasons or data) for each request.
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 action must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 2003-NM-89-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. 2003-NM-89-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.
[[Page 71048]]
Discussion
The FAA has received a report indicating that the primary brake of a horizontal stabilizer trim actuator (HSTA) removed from a Boeing Model 757-200 series airplane did not perform at the expected level during a pre-overhaul test at a repair facility. The HSTA brake system is made up of one primary brake and two secondary brakes; these brakes are used to hold the stabilizer against air loads. The secondary brakes provide a backup function to the primary brake.
Investigation revealed that the diminished brake performance was caused by grease from the thrust bearings, which was found on the primary brake surface. Since the first report of grease contamination, the FAA has also received reports of grease contamination on the HSTA primary brake(s) during overhaul on several Model 757-200 series airplanes. In addition, the FAA has received reports that all ballscrew assemblies on HSTAs that have been recently overhauled showed corrosion or wear; and that corrosion or cracking was found during HSTA overhaul in some differential assemblies.
Grease contamination on the primary HSTA brake, if not corrected, could result in the loss of the primary brake function, which, in combination with the loss of the secondary HSTA brake function, could result in loss of control of the airplane.
Explanation of Relevant Service Information
The FAA has reviewed and approved Boeing Alert Service Bulletin, 757-27A0142, Revision 2, dated October 23, 2003 (for Model 757-200, - 200CG, and -200PF series airplanes), which describes procedures for repetitive testing of the secondary HSTA brakes, and repetitive overhauls of the primary brake, ballscrew assembly, and differential assembly of the HSTA. The service bulletin recommends compliance times for the overhaul that range between two years and five years depending upon the total hours accumulated on the HSTA since delivery or since the most recent overhaul of the primary brake, ballscrew assembly, and differential assembly.
The FAA has also reviewed and approved Boeing Alert Service Bulletin 757-27A0143, Revision 1, dated October 23, 2003 (for Model 757-300 series airplanes), which describes procedures for repetitive overhauls of the primary brake, ballscrew assembly, and differential assembly of the HSTA.
Accomplishment of the actions specified in the service bulletins are intended to adequately address the identified unsafe condition.
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 require accomplishment of the actions specified in the service bulletins described previously, except as discussed below.
Difference Between the Proposed Rule and Service Bulletin 757-27A0142
The manufacturer has noted that Boeing Alert Service Bulletin, 757- 27A0142, Revision 2, dated October 23, 2003 contains an inadvertent misstatement of compliance times in paragraph D. of Table 1.E., ``Compliance.'' The statement ``Test the HSTA secondary brake when the HSTA reaches 24,000 hours (4C) (this is currently a scheduled maintenance task),'' should state: ``For HSTAs that have accumulated 15,000 to 23,999 hours, test the HSTA secondary brake when the HSTA reaches 24,000 hours (4C) (this is currently a scheduled maintenance task), or within 500 hours after the effective date of this AD, whichever occurs later.'' Paragraph D. of the table should also include, as the second bulleted item, the following statement: ``For HSTAs that have accumulated 24,000 to 29,999 hours, test the HSTA secondary brake within 500 hours.''
Clarification Between Proposed Rule and Service Bulletins
Both service bulletins state that no more work is necessary on airplanes changed per previous releases of the service bulletins. We find this statement to be incorrect because it contradicts the procedures specified in those service bulletins. Both service bulletins added new procedures for overhaul of the ballscrew assembly and differential assembly of the HSTA that were not specified in the previous releases. Therefore, more work is necessary on airplanes changed per previous releases of the service bulletins.
Further, Boeing Service Bulletin 757-27A0142 states that the total hours accumulated on the HSTA should be calculated ``since delivery (of the airplane).'' However, paragraph (d) of this proposed AD would require compliance ``prior to the accumulation of the applicable number of flight hours since the date of issuance of the original Airworthiness Certificate or the date of issuance of the Export Certificate of Airworthiness, whichever occurs first.'' This decision is based on our determination that different operators may interpret ``since delivery'' differently. We find that our proposed terminology is generally understood within the industry and records will always exist that establish these dates with certainty.
Cost Impact
There are approximately 1,085 airplanes of the affected design in the worldwide fleet. The FAA estimates that 754 airplanes of U.S. registry would be affected by this proposed AD; 722 of the affected airplanes of U.S. registry are Model 757-200, -200PF, and -200CB series airplanes, and 32 are Model 757-300 series airplanes.
For the affected Model 757-200 and Model 757-300 series airplanes, the FAA estimates that it would take approximately 96 work hours per airplane to accomplish the proposed overhaul, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $4,704,960, or $6,240 per airplane, per overhaul cycle.
For the affected Model 757-200 series airplanes, the FAA estimates that it would take approximately 1 work hour per airplane to accomplish the proposed test of the HSTA secondary brake, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $46,930, or $65 per airplane, per secondary brake test.
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 proposed AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.
Regulatory Impact
The regulations proposed herein would not have a substantial direct effect 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, it is determined that this proposal would not have federalism implications under Executive Order 13132.
[[Page 71049]]
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
-
The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
-
Section 39.13 is amended by adding the following new airworthiness directive:
Boeing: Docket 2003-NM-89-AD.
Applicability: All Model 757-200, -200PF, -200CB, and -300 series airplanes, certificated in any category.
Compliance: Required as indicated, unless accomplished previously.
To prevent grease contamination on the primary HSTA brake and consequent loss of the primary brake function, which, in combination with the loss of the secondary HSTA brake function, could result in loss of control of the airplane, accomplish the following:
For Model 757-200, -200CB, and -200PF Series Airplanes: Repetitive Overhauls and Tests
(a) For Model 757-200, -200CB, and -200PF series airplanes: Except as provided by paragraph (c), (d), and (e) of this AD, at the applicable time specified in paragraph 1.E., ``Compliance,'' of Boeing Alert Service Bulletin 757-27A0142, Revision 2, dated October 23, 2003; including the compliance time ``since the most recent overhaul of the primary brake, the ballscrew assembly, and the differential assembly''; do the actions specified in paragraphs (a)(1) and (a)(2) of this AD.
(1) Test the secondary brakes of the HSTA per Part 2 of the Accomplishment Instructions of the service bulletin. If any secondary brake fails, before further flight, replace with a serviceable brake or overhaul per Part 2 of the Accomplishment Instructions of the service bulletin.
(2) Overhaul the primary brake, ballscrew assembly, and differential assembly of the horizontal stabilizer trim actuator (HSTA) per Part 1 of the Accomplishment Instructions of the service bulletin. Accomplishment of the overhaul constitutes terminating action for the repetitive tests of the secondary brake required by paragraph (a)(1) of this AD.
(b) Repeat the overhaul of the primary brake, ballscrew assembly, and differential assembly of the HSTA at intervals not to exceed 30,000 flight hour intervals, per the Accomplishment Instructions of Boeing Alert Service Bulletin 757-27A0142, Revision 2, dated October 23, 2003.
(c) Where the service bulletin specified in paragraph (a) of this AD specifies a date from which the initial compliance time interval starts as being the date of the initial release of the service bulletin, this AD requires compliance within the applicable initial compliance time after the effective date of this AD.
(d) Where the service bulletin specified in paragraph (a) of this AD states ``total hours since delivery,'' this AD requires compliance prior to the accumulation of the applicable number of flight hours since the date of issuance of the original Airworthiness Certificate or the date of issuance of the Export Certificate of Airworthiness, whichever occurs first.
(e) Where paragraph D. of the table in paragraph 1.E., ``Compliance,'' of the service bulletin specified in paragraph (a) of this AD states: ``Test the HSTA secondary brake when the HSTA reaches 24,000 hours (4C) (this is currently a scheduled maintenance task)''; this AD requires testing secondary brakes that have accumulated between 15,000 and 23,999 flight hours when the HSTA reaches 24,000 flight hours or within 500 flight hours after the effective date of this AD, whichever occurs later. For HSTAs that have accumulated between 24,000 and 29,999 flight hours, this AD requires testing the secondary brake within 500 flight hours after the effective date of this AD. All testing should be done in accordance with the service bulletin.
For Model 757-300 Series Airplanes: Repetitive Overhauls
(f) For Model 757-300 series airplanes: Prior to the accumulation of 30,000 total flight hours, overhaul the primary brake, ballscrew assembly, and differential assembly of the HSTA per the Accomplishment Instructions of Boeing Alert Service Bulletin 757-27A0143, Revision 1, dated October 23, 2003. Repeat the overhaul thereafter at intervals not to exceed 30,000 flight hours.
Overhauls Accomplished Per Previous Issues of Service Bulletins
(g) Overhauls of the primary brake and tests of the secondary brakes accomplished before the effective date of this AD per Boeing Alert Service Bulletin 757-27A0142, dated February 13, 2003, or, Revision 1, dated April 10, 2003; and overhauls of the primary brake accomplished before the effective date of this AD per Boeing Alert Service Bulletin 757-27A0143, dated February 13, 2003; are considered acceptable for compliance with the overhaul of the primary brake only and tests of the secondary brakes specified in this AD.
Alternative Methods of Compliance
(h) In accordance with 14 CFR 39.19, the Manager, Seattle Aircraft Certification Office (ACO), FAA, is authorized to approve alternative methods of compliance (AMOCs) for this AD.
Issued in Renton, Washington, on December 12, 2003. Kevin M. Mullin, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 03-31443 Filed 12-19-03; 8:45 am]
BILLING CODE 4910-13-P
