[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

[[Page 24572]]

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]
BILLING CODE 4910-13-U