[Federal Register Volume 62, Number 161 (Wednesday, August 20, 1997)]
[Rules and Regulations]
[Pages 44204-44206]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-21773]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-124-AD; Amendment 39-10104; AD 97-17-02]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 777-200 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 certain Boeing Model 777-200 series airplanes. This 
action requires repetitive torquing of the bushing retainer nuts of the 
pivot pins in the horizontal stabilizer hinge assembly to tighten loose 
nuts to the new torque value; and repetitive visual inspections, if 
necessary, to detect bushing migration or damage to adjacent 
structures, and repair of any damage. This proposal also provides for 
an optional terminating action for the repetitive inspections. This 
amendment is prompted by a report of a loose bushing retainer nut, 
which may be attributed to low nut torque. The actions specified in 
this AD are intended to detect and correct loose bushing retainer nuts 
of the pivot pins in the horizontal stabilizer hinge assembly, which 
could result in bushing migration and consequent damage to the adjacent 
structure, and reduced controllability of the airplane.

DATES: Effective September 4, 1997.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of September 4, 1997.
    Comments for inclusion in the Rules Docket must be received on or 
before October 20, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 97-NM-124-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: Stan Wood, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington; telephone (425) 227-2772; 
fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: Boeing recently notified the FAA that an 
unsafe condition may exist on certain Boeing Model 777-200 series 
airplanes. Investigation revealed that a loose bushing retainer nut of 
the pivot pin in the horizontal stabilizer hinge assembly was found on 
a Boeing Model 777-200 flight test airplane that had accumulated 
approximately 2,000 total flight cycles. The cause of the loose bushing 
retainer nut may be attributed to low nut torque. A loose bushing 
retainer nut of the pivot pin in the horizontal stabilizer hinge 
assembly, if not corrected, could result in bushing migration and 
consequent damage to the adjacent structure, and reduced 
controllability of the airplane.

[[Page 44205]]

Explanation of Relevant Service Information

    Boeing has issued Service Bulletin 777-53-0006, dated May 8, 1997, 
which describes procedures for repetitive inspections of the bushing 
retainer nuts of the pivot pins in the horizontal stabilizer hinge 
assembly to detect and correct loose bushing retainer nuts, migration 
of the bushings, or damage to adjacent structures. This service 
bulletin also describes optional procedures for tightening the bushing 
retainer nuts to a torque level of 1,000 to 1,500 in-lbs. In addition, 
this service bulletin describes procedures for tightening the bushing 
retainer nuts and installing anti-rotation brackets to prevent the nuts 
from rotating, which would eliminate the need for repetitive 
inspections.

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 777-200 series airplanes of the 
same type design, this AD is being issued to detect and correct loose 
bushing retainer nuts of the pivot pins in the horizontal stabilizer 
hinge assembly, which could result in bushing migration and consequent 
damage to the adjacent structure, and reduced controllability of the 
airplane. This action requires repetitive torquing of the bushing 
retainer nuts of the pivot pins in the horizontal stabilizer hinge 
assembly to tighten loose nuts to the new torque value of 1,000 to 
1,500 in-lbs; and repetitive visual inspections, if necessary, to 
detect bushing migration or damage to adjacent structures. This 
proposal also provides for an optional action of installing brackets to 
prevent rotation of the bushing retainer nuts, which would constitute 
termination for the repetitive inspections. These actions are required 
to be accomplished in accordance with the service bulletin described 
previously.

Differences Between the AD and the Relevant Service Information

    Operators should note that, although Boeing Service Bulletin 777-
53-0006 provides procedures to eliminate the need for repetitive 
inspections after accomplishment of a third inspection (2,150 flight 
cycles), this AD requires repetitive inspections at intervals not to 
exceed 1,000 flight cycles, until accomplishment of the terminating 
action. In developing an appropriate compliance time for this AD, the 
FAA has determined that the repetitive inspections should not be 
extended to a third inspection (2,150 flight cycles) and that, in order 
to provide an acceptable level of safety, repetitive intervals should 
not exceed 1,000 flight cycles.
    Operators should also note that, although the service bulletin 
specifies that the manufacturer must be contacted for instructions in 
the repair of damage, this AD requires the repair to be accomplished in 
accordance with a method approved by the FAA.

Interim Action

    The FAA is considering further rulemaking to supersede this AD to 
require installing anti-rotation brackets to prevent the nuts from 
rotating. However, the planned compliance time for accomplishment of 
this action is sufficiently long so that prior notice and time for 
public comment will be practicable.

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-124-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.

[[Page 44206]]

Sec. 39.13  [Amended]

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

97-17-02  Boeing: Amendment 39-10104. Docket 97-NM-124-AD.

    Applicability: Model 777-200 series airplanes, line numbers 3, 
5, 7 through 9 inclusive, 11 through 13 inclusive, 15 through 17 
inclusive, and 19 through 22 inclusive; 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 (d) 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 loose bushing retainer nuts of the pivot 
pins in the horizontal stabilizer hinge assembly, which could result 
in bushing migration and consequent damage to the adjacent 
structure, and reduced controllability of the airplane, accomplish 
the following:
    (a) Within 150 flight cycles after the effective date of this 
AD, torque the bushing retainer nuts to the new torque value of 
1,000 to 1,500 in-lbs, in accordance with Figure 2 of the Boeing 
Service Bulletin 777-53-0006, dated May 8, 1997. Repeat the torquing 
thereafter at intervals not to exceed 1,000 flight cycles.

    Note 2: Where there are differences between the AD and the 
service bulletin, the AD prevails.

    (b) If any bushing retainer nut is loose and is not correctly 
attached to the bushing, prior to further flight, perform a visual 
inspection to determine whether bushing migration has occurred, in 
accordance with Figure 2 of the Boeing Service Bulletin 777-53-0006, 
dated May 8, 1997.
    (1) If bushing migration has not occurred, prior to further 
flight, tighten the bushing retainer nuts in accordance with Figure 
2 of the service bulletin. Repeat the visual inspection thereafter 
at intervals not to exceed 1,000 flight cycles.
    (2) If bushing migration has occurred, prior to further flight, 
inspect/replace the bushing and other affected components and repair 
any damage, in accordance with a method approved by the Manager, 
Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane 
Directorate.
    (c) Accomplishment of installing an anti-rotation bracket in 
accordance with Figure 3 of Boeing Service Bulletin 777-53-0006, 
dated May 8, 1997, constitutes terminating action for the repetitive 
inspection requirements of this AD.
    (d) 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (e) 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.
    (f) Certain actions shall be done in accordance with Boeing 
Service Bulletin 777-53-0006, dated May 8, 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.
    (g) This amendment becomes effective on September 4, 1997.

    Issued in Renton, Washington, on August 11, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-21773 Filed 8-19-97; 8:45 am]
BILLING CODE 4910-13-U