[Federal Register Volume 64, Number 33 (Friday, February 19, 1999)]
[Rules and Regulations]
[Pages 8230-8232]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-3726]
[[Page 8230]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-320-AD; Amendment 39-11044; AD 99-04-19]
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 detailed visual inspections to detect cracking of
the cove skin on the outboard leading edge slats; a slat adjustment
check; and corrective actions, if necessary. This amendment is prompted
by reports of fatigue cracking and/or missing pieces of the cove skin
on the outboard leading edge slats. The actions specified in this AD
are intended to detect and correct such discrepancies, which could
result in skin separation or structural damage to the leading edge
slats, and consequent reduced controllability of the airplane.
DATES: Effective March 8, 1999.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of March 8, 1999.
Comments for inclusion in the Rules Docket must be received on or
before April 20, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 98-NM-320-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: The FAA has received several reports of
fatigue cracking and/or missing pieces of the cove skin and on the
outboard leading edge slats on the left and right wings on Boeing Model
777 series airplanes. On four airplanes that had accumulated between
3,000 and 14,000 flight hours and 650 and 2,800 flight cycles, cracking
was located on slat numbers 4, 5, and 9. On one airplane that had
accumulated 4,530 total flight hours and 685 total flight cycles, the
cracked and missing pieces were located on slat numbers 5 and 10. On
another airplane that had accumulated 1,140 total flight hours and
1,525 total flight cycles, a portion of the leading edge wedge was
missing, and cracking in the cove skin at the deflection control ribs
on slat number 5 was detected. At this time, the exact cause of the
cracking is unknown. These conditions, if not detected and corrected,
could result in skin separation or structural damage to the outboard
leading edge slats, and consequent reduced controllability of the
airplane.
Explanation of Relevant Service Information
The FAA has reviewed and approved Boeing Alert Service Bulletin
777-57A0034, Revision 2, dated November 19, 1998, which, among other
things, describes procedures for repetitive detailed visual inspections
to detect cracking of the cove skin on the outboard leading edge slats;
a slat adjustment check to verify proper adjustment of the slat
rigging; and corrective actions, if necessary. The corrective actions
include stop drilling of any crack that is 1.5 inches or less as an
interim action; replacement of the leading edge slat; and adjustment of
the slat, if necessary. Accomplishment of the actions specified in the
alert service bulletin is intended to adequately address the identified
unsafe condition.
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 cracking and/or missing pieces of
the cove skin on the outboard leading edge slats on the left and right
wings, which could result in skin separation or structural damage to
the leading edge slats, and consequent reduced controllability of the
airplane. This AD requires accomplishment of the actions specified in
the alert service bulletin described previously, except as discussed
below.
Differences Between This Rule and Alert Service Bulletin
The alert service bulletin specifies that the manufacturer may be
contacted for disposition of certain repair conditions. However, this
AD requires the repair of those conditions to be accomplished in
accordance with a method approved by the FAA.
The alert service bulletin also specifies that the inspection of
the interior structure of the cove skin be accomplished repetitively.
This AD does not require repetitive interior inspections of this area,
because the FAA has determined that the repetitive detailed visual
inspections of the exterior structure of the cove skin required by this
AD are adequate to detect cracking in the subject area.
The flow chart in Figure 1. of the alert service bulletin does not
accurately describe the mandatory corrective actions addressed in this
rule. There have been recent instances involving cracking of the slats
where it was determined that the slats were properly rigged, therefore,
the FAA is uncertain of the cause for the cracking and is not relying
on the rigging checks to assure crack free structure. The FAA has
determined that the slat adjustment check cited in the flow chart does
not adequately address the identified unsafe condition; therefore, this
AD does not require accomplishment of this action at the intervals
specified.
Interim Action
This 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
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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 98-NM-320-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:
99-04-19 Boeing: Amendment 39-11044. Docket 98-NM-320-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 (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 cracking and/or missing pieces of the cove
skin on the outboard leading edge slats on the left and right wings,
which could result in skin separation or structural damage to the
leading edge slats, and consequent reduced controllability of the
airplane, accomplish the following:
Note 2: Where there are differences between the alert service
bulletin and the AD, the AD prevails.
(a) Prior to the accumulation of 500 total flight cycles, or
within 30 days after the effective date of this AD, whichever occurs
later: Perform a detailed visual inspection to detect cracking of
the cove skin on the outboard leading edge slats of the left and
right wings at slat numbers 1 through 6 inclusive, and 9 through 14
inclusive; in accordance with Boeing Alert Service Bulletin 777-
57A0034, Revision 2, dated November 19, 1998. Repeat the inspection
thereafter at intervals not to exceed 350 flight cycles.
(b) If any cracking is detected during any inspection required
by paragraph (a) of this AD, prior to further flight, accomplish the
actions specified in paragraph (b)(1), (b)(2), or (b)(3) of this AD,
as applicable, in accordance with Boeing Alert Service Bulletin 777-
57A0034, Revision 2, dated November 19, 1998.
(1) For any crack that is less than or equal to 1.5 inches in
length, stop drill the crack. Within 5 days following accomplishment
of the stop drilling accomplish paragraphs (b)(1)(i) and (b)(1)(ii)
of this AD.
(i) Perform a detailed visual inspection of the interior
structure of the cove skin at slat numbers 1 through 6 inclusive,
and 9 through 14 inclusive, in accordance with Part 2 of the
Accomplishment Instructions of the alert service bulletin.
(A) If no crack is detected, prior to further flight, accomplish
a slat adjustment check, and if any slat is not adjusted within the
limits, adjust the slat to within the limits; in accordance with
Part 3 of the Accomplishment Instructions of the alert service
bulletin.
(B) If any crack is detected, prior to further flight, replace
the slat with a new slat, and accomplish a slat adjustment in
accordance with Part 2 of the Accomplishment Instructions of the
alert service bulletin.
(ii) Repair any cracked cove skin in accordance with a method
approved by the Manager, Seattle Aircraft Certification Office
(ACO), FAA, Transport Airplane Directorate.
(2) For any crack that is greater than 1.5 inches in length,
prior to further flight, accomplish paragraphs (b)(2)(i) and
(b)(2)(ii) of this AD.
(i) Perform the inspection required by paragraph (b)(1)(i) of
this AD in accordance with Part 2 of the Accomplishment Instructions
of the alert service bulletin.
(A) If no crack is detected, prior to further flight, accomplish
a slat adjustment check, and if any slat is not adjusted within the
limits, adjust the slat to within the limits; in accordance with
Part 3 of the Accomplishment Instructions of the alert service
bulletin.
(B) If any crack is detected, prior to further flight, replace
the slat with a new slat and accomplish a slat adjustment in
accordance with Part 2 of the Accomplishment Instructions of the
alert service bulletin.
(ii) Repair any cracked cove skin in accordance with a method
approved by the Manager, Seattle ACO.
(3) Replace the slat with a new slat and accomplish a slat
adjustment in accordance with Part 2 of the Accomplishment
Instructions of the alert service bulletin.
(c) 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.
(d) 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.
(e) The actions shall be done in accordance with Boeing Alert
Service Bulletin 777-
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57A0034, Revision 2, dated November 19, 1998. 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.
(f) This amendment becomes effective on March 8, 1999.
Issued in Renton, Washington, on February 9, 1999.
John J. Hickey,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-3726 Filed 2-18-99; 8:45 am]
BILLING CODE 4910-13-U
