[Federal Register Volume 68, Number 245 (Monday, December 22, 2003)]
[Proposed Rules]
[Pages 71047-71049]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-31443]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[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).

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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: 
[email protected]. 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

    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:

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]
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