[Federal Register Volume 62, Number 87 (Tuesday, May 6, 1997)]
[Rules and Regulations]
[Pages 24570-24572]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-11524]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-NM-67-AD; Amendment 39-10014; AD 97-10-02]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 777 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This amendment adopts a new airworthiness directive (AD) that
is applicable to all Boeing Model 777 series airplanes. This action
requires repetitive corrosion/resistance inspections to measure the
resistance of each wire bundle of the flight control system; and repair
of the receptacle bond, repair of the bundle connector backshells, or
replacement of the wire bundles with new components, if necessary. This
amendment is prompted by reports of corroded connectors and numerous
other discrepancies of the wire bundles, such as loose backshells and
loose shield retention bands, due to the presence of moisture inside
the wire bundles. The actions specified in this AD are intended to
detect and correct such corrosion, which could reduce system protection
against lightning strikes or high intensity radiated field (HIRF)
events, and consequently could adversely affect wire bundles used for
the flight control system. This situation could result in loss of
function of certain flight control surface actuators in the event of a
lightning strike.
DATES: Effective May 21, 1997.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of May 21, 1997.
Comments for inclusion in the Rules Docket must be received on or
before July 7, 1997.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 97-NM-67-AD, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056.
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 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.
FOR FURTHER INFORMATION CONTACT: Chris Hartonas, Aerospace Engineer,
Systems and Equipment Branch, ANM-130S, FAA, Transport Airplane
Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue,
SW., Renton, Washington 98055-4056; telephone (206) 227-2864; fax (206)
227-1181.
SUPPLEMENTARY INFORMATION: The FAA has received reports of corrosion
between the backshell and bundle shield, loose shield retention bands,
and loose backshells of the wire bundles of the flight control system
on Boeing Model 777 series airplanes. Investigation revealed wire
bundles with higher than specified resistance (which is an indicator of
corrosion) between the receptacles and mounting brackets and between
the brackets and structure. The cause of such corrosion has been
attributed to the existing design of the wire bundles, which allows
moisture to collect inside the wire bundle connectors. Corrosion in the
subject area, if not detected and corrected in a timely manner, could
reduce system protection against lightning strikes or high intensity
radiated field (HIRF) events, which could adversely affect wire bundles
used for the flight control system, and consequently result in loss of
function of certain flight control surface actuators in the event of a
lightning strike.
Explanation of Relevant Service Information
The FAA has reviewed and approved Boeing Alert Service Bulletin
777-27A0019, dated April 3, 1997, which describes procedures for
repetitive corrosion/resistance inspections to measure the resistance
of each wire bundle of the flight control system; and, if any
discrepancy is found, repair of the receptacle bond, repair of the
bundle connector backshells, or replacement of the wire bundles with
new components, if necessary. Accomplishment of the inspection will
ensure that the wiring maintains shield continuity, which reduces
system sensitivity to an lightning strike or a HIRF event.
Explanation of the Requirements of the Rule
Since an unsafe condition has been identified that is likely to
exist or develop on other Boeing Model 777 series airplanes of the same
type design, this AD is being issued to detect and correct corrosion in
the wire bundles of the flight control system, which could reduce the
system protection against lightning strikes or HIRF events, which could
adversely affect wire bundles used for the flight control system, and
consequently result in loss of function of certain flight control
surface actuators in the event of a lightning strike. This AD requires
repetitive corrosion/resistance inspections to measure the resistance
of each wire bundle of the flight control system; and, if any
discrepancy is found, repair of the receptacle bond, repair of the
bundle connector backshells, or replacement of wire bundles with new
components, if necessary. These actions are required to be accomplished
in accordance with the alert service bulletin described previously.
In addition, this AD provides for an optional terminating action
that involves replacing existing wire bundle connectors with new
overmolded connectors. The FAA has determined that this action will
preclude the collection of moisture inside the wire bundles and
consequent corrosion of the components. This option is to be
accomplished in accordance with a method approved by the FAA, and
constitutes terminating action for the repetitive inspection
requirements of this AD.
The compliance times for accomplishing the inspections are
dependent upon the time elapsed since the first production test flight
of the airplane. Airplanes that have reached or exceeded 12 months from
the time of the first production test flight of the airplane are to be
inspected within 60 days after the effective date of the AD. For
airplanes that have not yet reached or exceeded 12 months since the
time of the first production test flight, the initial inspection is not
required until the airplane reaches that threshold. The FAA notes that
the required compliance time of within 12 months after the first
production flight test is usually sufficient to allow for a brief
comment period before adoption of a final rule. However, in this AD,
the compliance time of 12 months was selected based on the following
factors. The FAA considered not only the degree of
[[Page 24571]]
urgency associated with addressing the subject unsafe condition, but
the manufacturer's recommendation as to an appropriate compliance time;
the fact that the unsafe condition involves corrosion, which is
associated with passage of time; and the fact that the times the first
production flight test occurs will significantly vary the date the
compliance time must be met for these airplanes. The FAA considers
that, by allowing airplanes to reach or exceed 12 months before
performing the initial inspection, no undue burden is created for the
operators; rather, this compliance time will enable operators to
continue to operate for a time that does not adversely affect the
operational safety of these airplanes.
Interim Action
This AD is considered to be interim action until final action is
identified, at which time the FAA may consider further rulemaking.
Determination of Rule's Effective Date
Since a situation exists that requires the immediate adoption of
this regulation, it is found that notice and opportunity for prior
public comment hereon are impracticable, and that good cause exists for
making this amendment effective in less than 30 days.
Comments Invited
Although this action is in the form of a final rule that involves
requirements affecting flight safety and, thus, was not preceded by
notice and an opportunity for public comment, comments are invited on
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All
communications received on or before the closing date for comments will
be considered, and this rule may be amended in light of the comments
received. Factual information that supports the commenter's ideas and
suggestions is extremely helpful in evaluating the effectiveness of the
AD action and determining whether additional rulemaking action would be
needed.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the rule that might
suggest a need to modify the 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 that
summarizes each FAA-public contact concerned with the substance of this
AD will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this rule must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 97-NM-67-AD.'' The postcard will be date stamped and
returned to the commenter.
Regulatory Impact
The regulations adopted herein will 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 final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
The FAA has determined that this regulation is an emergency
regulation that must be issued immediately to correct an unsafe
condition in aircraft, and that it is not a ``significant regulatory
action'' under Executive Order 12866. It has been determined further
that this action involves an emergency regulation under DOT Regulatory
Policies and Procedures (44 FR 11034, February 26, 1979). If it is
determined that this emergency regulation otherwise would be
significant under DOT Regulatory Policies and Procedures, a final
regulatory evaluation will be prepared and placed in the Rules Docket.
A copy of it, if filed, 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
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
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:
97-10-02 Boeing: Amendment 39-10014. Docket 97-NM-67-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
otherwise 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 detect and correct corrosion, which could reduce system
protection against lightning strikes or high intensity radiated
field (HIRF) events, adversely affect wire bundles used for the
flight control system, and result in loss of function of certain
flight control surface actuators, accomplish the following:
(a) Within 12 months after first production test flight of the
airplane, or within 60 days, whichever comes later, perform an
inspection to determine the part number (P/N) of each wire bundle
connector at the wheel well disconnects, as listed in the table in
paragraph D. of the Accomplishment Instructions of Boeing Alert
Service Bulletin 777-27A0019, dated April 3, 1997; and to determine
if the wire bundle has a molded backshell; in accordance with
paragraph C. of the Accomplishment Instructions in the previously
referenced alert service bulletin.
(1) If any wire bundle has P/N S280W655-( ) and has a molded
backshell, no further action is required by paragraph (a) of this
AD.
(2) If any wire bundle does not have a molded backshell, prior
to further flight, perform a corrosion/resistance inspection to
measure the resistance of each bundle in accordance with paragraph
D. of the Accomplishment Instructions in the alert service bulletin.
(b) If, during any corrosion/resistance inspection required by
this AD, the resistance of any wire bundle is found to be 150
milliohms or less, repeat the corrosion/resistance inspection
required by paragraph (a) of this AD thereafter at intervals not to
exceed 7 months.
(c) If, during any corrosion/resistance inspection required by
this AD, the resistance of any wire bundle is found to be greater
than 150 milliohms, prior to further flight, repair the receptacle
bond, repair the bundle connector backshells, or replace the wire
bundles, in accordance with paragraph H. of the Accomplishment
Instructions in Boeing Alert Service Bulletin 777-27A0019, dated
April 3, 1997. Repeat the corrosion/resistance
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inspection required by paragraph (a) of this AD at the time
specified in paragraph (c)(1) or (c)(2) of this AD, as applicable.
(1) For airplanes on which any wire bundle has been replaced:
Within 12 months after installation of the new wire bundle,
accomplish the corrosion/resistance inspection required by paragraph
(a) of this AD; and thereafter, repeat that inspection at intervals
not to exceed 7 months.
(2) For airplanes on which any receptacle bond or bundle
connector backshells have been repaired: Repeat the corrosion/
resistance inspection required by paragraph (a) of this AD
thereafter at intervals not to exceed 7 months.
(d) Replacement of existing wire bundle connectors with new
overmolded connectors, in accordance with a method approved by the
Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport
Airplane Directorate, constitutes a terminating action for the
repetitive inspection requirements of this AD.
(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 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 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
(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.
(g) Certain action(s) shall be done in accordance with Boeing
Alert Service Bulletin 777-27A0019, dated April 3, 1997. 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.
(h) This amendment becomes effective on May 21, 1997.
Issued in Renton, Washington, on April 28, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 97-11524 Filed 5-5-97; 8:45 am]
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