[Federal Register Volume 64, Number 120 (Wednesday, June 23, 1999)]
[Rules and Regulations]
[Pages 33390-33392]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-15778]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 99-NM-116-AD; Amendment 39-11198; AD 99-13-05]
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 certain Boeing Model 777 series airplanes. This action
requires repetitive inspections to detect cracking of the upper cutout
and lower flange of the outboard support assembly of the flaperons on
the wings; and corrective actions, if necessary. This amendment also
provides an optional terminating action for the repetitive inspections.
This amendment is prompted by results of flight testing conducted by
the manufacturer indicating that high engine thrust conditions during
takeoff cause excessive cyclic loads and could lead to fatigue cracking
of the outboard support of the flaperon. The actions specified in this
AD are intended to detect and correct such fatigue cracking, which
could result in fracture of the flaperon support structure, loss of the
flaperon, and consequent reduced controllability of the airplane.
DATES: Effective July 8, 1999.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of July 8, 1999.
Comments for inclusion in the Rules Docket must be received on or
before August 23, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 99-NM-116-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, Transport Airplane Directorate, Seattle
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (425) 227-2772; fax (425) 227-1181.
SUPPLEMENTARY INFORMATION: Results of flight testing of the Boeing
Model 777 series airplane indicate that high engine thrust conditions
during takeoff cause excessive cyclic loads on the flaperon support
structure of the flaperons on the left and right wings. Based on
engineering analysis of the flaperon support structure, it was
determined that due to the reduced fatigue life of the affected parts,
fatigue cracks could develop on the outboard support of the flaperons.
For airplanes powered by Rolls-Royce engines, it was determined that
fatigue cracks could occur prior to the accumulation of 4,000 total
flight cycles; and for airplanes powered by General Electric and Pratt
& Whitney engines, fatigue cracks could occur prior to the accumulation
of 10,000 total flight cycles. Such fatigue cracking of the outboard
support of the flaperons, if not detected and corrected, could result
in fracture of the flaperon support structure, loss of the flaperon,
and consequent reduced controllability of the airplane.
Explanation of Relevant Service Information
The FAA has reviewed and approved Boeing Alert Service Bulletin
777-57A0008, dated March 25, 1999, which describes procedures for
accomplishment of repetitive high frequency eddy current (HFEC)
inspections to detect cracking of the upper cutout and lower flange of
the outboard support assembly of the flaperons on the left and right
wings; and corrective actions, if necessary. The corrective actions
include modification of the fairings of the outboard flaperon;
modification of the lower panels of the fixed trailing edge of the
outboard flaperon; replacement of the existing outboard support, the
outboard support bearing block, and the upper panel bracket of the
fixed trailing edge of the flaperons on each wing with new components;
and an operational test to detect fuel leakage.
In addition, the service bulletin describes procedures for
accomplishment of modification of the inboard aft fairing assembly of
the flaperons to be accomplished concurrently with the modification of
the outboard support assemblies. These procedures include modification
of the aft fairing of the inboard support and replacement of the
existing inboard support bearing block with a new block.
Accomplishment of the modifications described previously eliminates
the need for the 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 airplanes of the same type design, this AD is
being issued to detect and correct fatigue cracking of the outboard
support assembly of the flaperons on each wing, which could result in
fracture of the flaperon support structure, loss of the flaperon, and
consequent reduced controllability of the airplane. This AD requires
accomplishment of the actions specified in the service bulletin
described previously, except as discussed below. In addition, this AD
provides an optional terminating action for the repetitive inspections.
Differences Between This Rule and Alert Service Bulletin
The alert service bulletin specifies that the manufacturer may be
contacted for disposition of certain cracking conditions, in lieu of
accomplishment of the terminating action. However, if any cracking is
detected, this AD requires accomplishment of the terminating action
prior to further flight.
The alert service bulletin specifies that certain corrective
actions required by this AD may be accomplished in accordance with the
Airplane Maintenance Manual or an operator's ``equivalent procedure.''
However, this AD requires that any such actions be
[[Page 33391]]
accomplished only in accordance with the procedures specified in the
Airplane Maintenance Manual. An ``operator's equivalent procedure'' may
be used only if approved as an alternative method of compliance in
accordance with the provisions of this AD.
Interim Action
This is considered to be interim action. The FAA is currently
considering requiring modification of the outboard and inboard support
assemblies of the flaperons, as described in the alert service
bulletin, which would constitute terminating action for the repetitive
inspections required by this AD. However, the planned compliance time
for these actions is sufficiently long so that notice and opportunity
for prior 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 99-NM-116-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:
99-13-05 Boeing: Amendment 39-11198. Docket 99-NM-116-AD.
Applicability: Model 777 series airplanes, as listed in Boeing
Alert Service Bulletin 777-57A0008, dated March 25, 1999;
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 (f) 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 fatigue cracking of the outboard support
of the flaperon, which could result in fracture of the flaperon
support structure, loss of the flaperon, and consequent reduced
controllability of the airplane; accomplish the following:
Repetitive Inspections
(a) Perform high frequency eddy current (HFEC) inspections to
detect fatigue cracking of the upper cutout and lower flange of the
outboard support assembly of the flaperons on the left and right
wings, in accordance with Part 1 of the Accomplishment Instructions
of Boeing Alert Service Bulletin 777-57A0008, dated March 25, 1999,
at the time specified in paragraph (a)(1) or (a)(2) of this AD, as
applicable.
(1) For airplanes identified as Group 1 in the alert service
bulletin: Perform HFEC inspections prior to the accumulation of
10,000 total flight cycles, or within 225 flight cycles after the
effective date of this AD, whichever occurs later. Repeat the
inspections thereafter at intervals not to exceed 225 flight cycles.
(2) For airplanes identified as Group 2 in the alert service
bulletin: Perform HFEC inspections prior to the accumulation of
4,000 total flight cycles, or within 70 flight cycles after the
effective date of this AD, whichever occurs later. Repeat the
inspections thereafter at intervals not to exceed 70 flight cycles.
Corrective Action
(b) If any fatigue cracking is detected during any inspection
required by paragraph (a) of this AD: Prior to further flight,
concurrently accomplish the modifications specified in Parts 2 and 3
of the Accomplishment Instructions of Boeing Alert Service Bulletin
777-57A0008, dated March 25, 1999. Accomplishment of the
modifications constitutes terminating action for the repetitive
inspection requirements of this AD.
[[Page 33392]]
(c) If any fatigue cracking is detected, and Boeing Alert
Service Bulletin 777-57A0008, dated March 25, 1999, specifies that
corrective actions may be accomplished in accordance with an
operator's ``equivalent procedure:'' The actions must be
accomplished in accordance with the chapter of the Boeing 777
Airplane Maintenance Manual (AMM) specified in the alert service
bulletin.
Optional Terminating Action
(d) Concurrent accomplishment of the modifications specified in
Parts 2 and 3 of the Accomplishment Instructions of Boeing Alert
Service Bulletin 777-57A0008, dated March 25, 1999, constitutes
terminating action for the repetitive inspections required by this
AD.
Spares
(e) As of the effective date of this AD, no person shall install
any part identified in the ``Existing Part Number'' column of
Section 2.E. of Boeing Alert Service Bulletin 777-57A0008, dated
March 25, 1999, on any airplane.
Alternative Methods of Compliance
(f) 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), FAA, Transport Airplane Directorate. 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.
Special Flight Permits
(g) 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.
Incorporation by Reference
(h) The actions shall be done in accordance with Boeing Alert
Service Bulletin 777-57A0008, dated March 25, 1999. 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.
(i) This amendment becomes effective on July 8, 1999.
Issued in Renton, Washington, on June 10, 1999.
Dorenda D. Baker,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-15778 Filed 6-22-99; 8:45 am]
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