AD 2003-12-01

[Federal Register Volume 68, Number 113 (Thursday, June 12, 2003)]
[Rules and Regulations]
[Pages 35160-35162]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 03-14521]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-NM-64-AD; Amendment 39-13186; AD 2003-12-01]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 777 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to all Boeing Model 777 series airplanes, that requires 
either a one-time inspection or a review of the airplane maintenance 
records for both stabilizer trim control modules (STCM) of the trim 
system of the horizontal stabilizer to determine if STCMs having 
certain serial numbers are installed; and follow-on corrective actions, 
if necessary. This amendment also requires eventual replacement of 
affected STCMs with new or reworked STCMs, which would terminate the 
follow-on actions. The actions specified by this AD are intended to 
prevent an uncommanded stabilizer trim due to simultaneous failure of 
two static seals on one STCM, combined with failure of the automatic 
shutdown function of the stabilizer trim system. Such failures could 
result in loss of pitch control and consequent loss of control of the 
airplane. This action is intended to address the identified unsafe 
condition.

DATES: Effective July 17, 2003. The incorporation by reference of 
certain publications listed in the regulations is approved by the 
Director of the Federal Register as of July 17, 2003.

ADDRESSES: The service information referenced in this AD may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the Federal 
Aviation Administration (FAA), Transport Airplane Directorate, Rules 
Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of 
the Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.

FOR FURTHER INFORMATION CONTACT: Kenneth J. Fairhurst, Aerospace 
Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-
4056; telephone (425) 917-6456; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to all Boeing Model 777 series 
airplanes was published in the Federal Register on August 30, 2002 (67 
FR 55737). That action proposed to require either a one-time inspection 
or a review of the airplane maintenance records for both stabilizer 
trim control modules (STCM) of the trim system of the horizontal 
stabilizer to determine if STCMs having certain serial numbers (S/N) 
are installed; and follow-on corrective actions, if necessary. That 
action also proposed to require eventual replacement of affected STCMs 
with new or reworked STCMs, which would terminate the follow-on 
actions.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Requests To Change Paragraphs (b) and (d)

    Three commenters ask that certain wording in paragraphs (b) and (d) 
of the proposed AD be changed. Two commenters ask that the wording be 
changed to specify allowing installation of STCMs having S/Ns 006 
through 556 inclusive, if the part has been reworked and marked with an 
``R'' on the nameplate, or if MOOG Aircraft Group Service Bulletin 
Number 160300-27-124 is marked on the modification plate. The third 
commenter asks that the information phrase (modified and marked with an 
``R'' suffix) be removed from paragraph (b) of the proposed AD, and 
that ``unless reworked per Part 2 of the Work Instructions of Boeing 
Service Bulletin 777-27A0047, Revision 2, dated October 11, 2001,'' be 
added to paragraph (d) of the proposed AD.
    The FAA agrees with the commenters because Part 2 of the Work 
Instructions of the referenced service bulletin specifies procedures 
for the installation of STCMs that have been reworked and marked with 
an ``R'' on the nameplate, or that include MOOG Aircraft Group Service 
Bulletin Number 160300-27-124 on the modification plate. We also agree 
to remove the information phrase (modified and marked with an ``R'' 
suffix) from paragraph (b) of the final rule, because the STCM also can 
be marked with the MOOG service bulletin number. Paragraphs (b) and (d) 
of this final rule have been changed accordingly.

Requests To Change STCM Serial Numbers

    Two commenters state that the range of STCM S/Ns specified in the 
proposed AD section titled ``Explanation of Relevant Service 
Information'' is incorrect and should be changed. The first commenter 
states that the S/Ns in that section should be corrected to specify 006 
through 556 inclusive. The second commenter states that Part 2 of the 
Work Instructions of the referenced service bulletin references S/Ns 
006 through 549 inclusive (however, it actually specifies 006 through 
556 inclusive). The commenter states that S/Ns 006 through 556 are the 
correct S/Ns and recommends those numbers be specified throughout the 
proposed AD to eliminate any confusion. The commenter also states that 
listing airplanes having S/Ns 2 through 266 and 273, excluding line 
numbers 256, 258, and 260 through 263 inclusive, as being subject to 
the actions specified in service bulletin, could be misinterpreted. The 
commenter recommends that the S/Ns in the applicability of the proposed 
AD should match the S/Ns (006 through 556 inclusive) listed in MOOG 
Aircraft Group Service Bulletin Number 160300-27-124.

[[Page 35161]]

    Although we acknowledge and agree with both commenters' remarks on 
the section in the preamble of the proposed AD titled ``Explanation of 
Relevant Service Information,'' that section is not restated in this 
final rule.
    We do not agree with the second commenter's request to add S/Ns to 
the applicability specified in the final rule. In the section of the 
proposed AD titled ``Differences Between Service Information and This 
Proposed AD,'' we stated that we have determined that the proposed AD 
applies to all Model 777 series airplanes. The reason for this is that 
the subject STCMs are line-replaceable units and may have been 
installed on other airplanes not included in the effectivity of the 
referenced service bulletin. Therefore, no change to the final rule is 
necessary in this regard.

Request To Reduce Compliance Time for Terminating Action

    Two commenters ask that the compliance time for the terminating 
action specified in paragraph (b) of the proposed AD be reduced from 
``Within 2 years after the effective date of this AD'' to ``Within 1 
year after the effective date of this AD.'' The first commenter gives 
no reason for this request. The second commenter, the STCM component 
manufacturer, states that after inspecting 83 percent of STCMs with S/N 
006 through 556, the only requirement on the majority of the components 
was to stamp either the identification plate or the modification plate 
for the STCM. The commenter also notes that it has accommodated 
operators in getting their units inspected and returned within 10 days, 
and adds that a 2-year compliance period is not warranted.
    We do not agree to reduce the compliance time to ``Within 1 year 
after the effective date of this AD.'' In developing an appropriate 
compliance time for this terminating action, the FAA considered not 
only the degree of urgency associated with addressing the subject 
unsafe condition, but the practical aspect of doing the terminating 
action within an interval of time that parallels normal scheduled 
maintenance for the majority of affected operators. In addition, we 
find that the repetitive tests required by paragraph (a)(1) of the 
final rule, along with adequate maintenance, will provide an acceptable 
level of safety until the affected STCMs are replaced. However, 
operators are always permitted to accomplish the actions earlier than 
the compliance time specified in an AD. No change to the final rule is 
necessary in this regard.

Request for Editorial Changes

    One commenter suggests that the following editorial changes should 
be made to the proposed AD:
    [sbull] Change all references from ``the trim system of the 
horizontal stabilizer'' to ``the horizontal stabilizer trim system.''
    [sbull] Discussion section: Add the word ``airplane'' right before 
``nose-down,'' add that a single STCM seal failure can result in an 
uncommanded valve motion in the airplane nose-down direction, and add 
that two static seals in one STCM combined with failure of the 
automatic shutdown function could result in loss of pitch control and 
consequent loss of control of the airplane.
    [sbull] Add the date to the reference to Revision 2 of the service 
bulletin in the last paragraph of the Explanation of Relevant Service 
Information section.
    We do not agree that these are substantial changes, nor do they 
make any essential change to the unsafe condition specified in the 
proposed AD. Therefore, no change to the final rule is necessary in 
this regard.

Request for Clarification of Terminating Action

    One commenter recommends that the wording specified in paragraph 
(b) of the proposed AD be clarified. The commenter states that there 
has been confusion in the past, since the directions have been unclear 
to several operators and maintenance personnel in the field. The 
commenter reiterates the wording on page 5, Note 2, of MOOG Aircraft 
Group Service Bulletin Number 160300-27-124, and recommends adding it 
to paragraph (b) of the proposed AD to ensure that the STCM units that 
have already been modified are not removed from service.
    We agree with the commenter and have added a new Note 3 to this 
final rule, for clarification, which specifies that STCM assemblies 
that have been reworked and marked per Part 2 of the Work Instructions 
of Boeing Service Bulletin 777-27A0047, Revision 2, dated October 11, 
2001, are acceptable for compliance with paragraph (b) of this final 
rule. Subsequent notes have been renumbered accordingly.

Conclusion

    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes previously 
described. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    There are approximately 404 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 131 airplanes of U.S. registry 
will be affected by this AD.
    It will take approximately 1 work hour per airplane to accomplish 
the inspection/review, at an average labor rate of $60 per work hour. 
Based on these figures, the cost impact of the inspection/review 
required by this AD on U.S. operators is estimated to be $7,860, or $60 
per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the requirements of this AD 
action, and that no operator would accomplish those actions in the 
future if this 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.
    Should an operator be required to do the functional test, it will 
take approximately 1 work hour per airplane to accomplish, at an 
average labor rate of $60 per work hour. Based on these figures, the 
cost impact of the functional test on U.S. operators is estimated to be 
$60 per airplane, per test cycle.
    Should an operator be required to do the replacement, it will take 
approximately 3 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Required parts will be provided by the 
vendor at no cost to operators. Based on these figures, the cost impact 
of the replacement on U.S. operators is estimated to be $180 per 
airplane.

Regulatory Impact

    The regulations adopted herein will 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 final rule does not have federalism 
implications under Executive Order 13132.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44

[[Page 35162]]

FR 11034, February 26, 1979); and (3) 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 final 
evaluation has been prepared for this action and it is contained in the 
Rules Docket. A copy of it may be obtained from the Rules Docket at the 
location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

0
Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. Section 39.13 is amended by adding the following new airworthiness 
directive:

2003-12-01--Boeing: Amendment 39-13186. Docket 2002-NM-64-AD.

    Applicability: All Model 777 series airplanes, 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 (e) 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 an uncommanded stabilizer trim due to simultaneous 
failure of two static seals on one stabilizer trim control module 
(STCM), combined with failure of the automatic shutdown function of 
the stabilizer trim system, which could result in loss of pitch 
control and consequent loss of control of the airplane, accomplish 
the following:

One-Time Inspection/Review of Maintenance Records

    (a) Within 30 days after the effective date of this AD: Do 
either a one-time general visual inspection or a review of the 
airplane maintenance records of both STCMs of the trim system of the 
horizontal stabilizer to determine the serial numbers (S/N), per 
Part 2 of the Work Instructions of Boeing Service Bulletin 777-
27A0047, Revision 2, dated October 11, 2001. If any affected S/N (6 
through 556 inclusive) is found on either STCM, within 150 flight 
hours after doing the inspection or review, do the actions specified 
in either paragraph (a)(1) or (a)(2) of this AD. If no affected 
serial number is found, no further action is required by this AD.

    Note 2: For the purposes of this AD, a general visual inspection 
is defined as: ``A visual examination of an interior or exterior 
area, installation, or assembly to detect obvious damage, failure, 
or irregularity. This level of inspection is made from within 
touching distance unless otherwise specified. A mirror may be 
necessary to enhance visual access to all exposed surfaces in the 
inspection area. This level of inspection is made under normally 
available lighting conditions such as daylight, hangar lighting, 
flashlight, or droplight and may require removal or opening of 
access panels or doors. Stands, ladders, or platforms may be 
required to gain proximity to the area being checked.''

Follow-on Corrective Actions

    (1) Do a functional test of the trim system of the horizontal 
stabilizer per Part 1 of the Work Instructions of the service 
bulletin.
    (i) If a test condition of PASSED is reported per Part 1.A.1. of 
the service bulletin, or considered serviceable per Part 1.A.5.a. of 
the service bulletin, repeat the test at intervals not to exceed 150 
flight hours until the terminating action required by paragraph (b) 
of this AD is done.
    (ii) If a test condition of FAILED is reported, or if the 
stabilizer does not move, correct the condition as specified in the 
Boeing 777 Airplane Maintenance Manual, and repeat the functional 
test at intervals not to exceed 150 flight hours until the 
terminating action specified in paragraph (b) of this AD is done. If 
failure of either STCM is found during the test, before further 
flight, replace the affected STCM with a new or reworked STCM as 
required by paragraph (b) of this AD.
    (2) Replace any affected STCM with a new or reworked STCM as 
required by paragraph (b) of this AD.

Terminating Action

    (b) Except as provided by paragraphs (a)(1)(ii) and (a)(2) of 
this AD: Within 2 years after the effective date of this AD, replace 
any STCM having an affected serial number identified in paragraph 
(a) of this AD with a new or reworked STCM per Part 2 of the Work 
Instructions of Boeing Service Bulletin 777-27A0047, Revision 2, 
dated October 11, 2001. Such replacement ends the repetitive 
functional tests required by paragraph (a)(1) of this AD.

    Note 3: STCM assemblies having an affected serial number, as 
identified in paragraph (a) of this AD, that have been reworked and 
marked per Part 2 of the Work Instructions of Boeing Service 
Bulletin 777-27A0047, Revision 2, dated October 11, 2001, are 
acceptable for compliance with paragraph (b) of this AD.

Credit for Actions Accomplished Per Previous Revisions of Service 
Bulletin

    (c) Replacement of affected STCMs before the effective date of 
this AD per Boeing Alert Service Bulletin 777-27A0047, dated 
September 21, 2000; or Boeing Service Bulletin 777-27A0047, Revision 
1, dated November 2, 2000; is considered acceptable for compliance 
with paragraph (b) of this AD.

Part Installation

    (d) As of the effective date of this AD, no person may install 
on any airplane a STCM having S/N 6 through 556 inclusive, unless 
reworked and marked per Part 2 of the Work Instructions of Boeing 
Service Bulletin 777-27A0047, Revision 2, dated October 11, 2001.

Alternative Methods of Compliance

    (e) 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). 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 4: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permits

    (f) 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, provided there has 
been no known failure of any STCM during any functional test 
required by paragraph (a)(1) of this AD.

Incorporation by Reference

    (g) Unless provided otherwise in this AD, the actions shall be 
done in accordance with Boeing Service Bulletin 777-27A0047, 
Revision 2, dated October 11, 2001. This incorporation by reference 
was approved by the Director of the Federal Register in accordance 
with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from 
Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 
98124-2207. Copies may be inspected at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the 
Office of the Federal Register, 800 North Capitol Street, NW., suite 
700, Washington, DC.

Effective Date

    (h) This amendment becomes effective on July 17, 2003.

    Issued in Renton, Washington, on June 4, 2003.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 03-14521 Filed 6-11-03; 8:45 am]
BILLING CODE 4910-13-P