[Federal Register Volume 66, Number 229 (Wednesday, November 28, 2001)]
[Proposed Rules]
[Pages 59387-59390]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-29600]



[[Page 59387]]

-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-35-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 777 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to certain Boeing Model 777 
series airplanes, that currently requires repetitive inspections to 
detect cracking of the coveskin on the outboard leading edge slats, and 
corrective actions, if necessary. The existing AD also provides for an 
optional modification that significantly increases the repetitive 
inspection interval. This action would expand the applicability of this 
AD by mandating the currently required inspections, and corrective 
actions, if necessary, for additional airplanes. Also, for airplanes on 
which the optional modification has been accomplished, this action 
would require a new one-time inspection for undersized seal inserts in 
the spanwise bulb seals on certain slats, and replacement of seal 
assemblies with new assemblies, if necessary. These actions are 
necessary to detect and correct cracking or missing pieces of the 
coveskin, or undersized seal inserts installed in the spanwise bulb 
seals, on the outboard leading edge slats on the wings, which could 
result in skin separation or structural damage to the leading edge 
slats and consequent reduced controllability of the airplane. This 
action is intended to address the identified unsafe condition.

DATES: Comments must be received by January 14, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2001-NM-35-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2001-NM-35-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.
    The service information referenced in the proposed rule 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.

FOR FURTHER INFORMATION CONTACT: Stan Wood, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2772; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed 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 above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this action may be changed in 
light of the comments received.
    Submit comments using the following format:
     Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
     For each issue, state what specific change to the proposed 
AD is being requested.
     Include justification (e.g., reasons or data) for each 
request.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2001-NM-35-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 2001-NM-35-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On September 14, 2000, the FAA issued AD 2000-19-08, amendment 39-
11909 (65 FR 57282, September 22, 2000), applicable to certain Boeing 
Model 777 series airplanes, to require repetitive detailed visual 
inspections to detect cracking of the coveskin on the outboard leading 
edge slats, and corrective actions, if necessary. That AD also provides 
for an optional modification that significantly increases the 
repetitive inspection interval. That action was prompted by findings of 
increased vibration of the coveskins due to air leaking and resonating 
within the cavity between the fixed leading edge and the coveskin; the 
vibration can result in fatigue cracking and high fatigue loads. The 
requirements of that AD are intended to detect and correct cracking 
and/or missing pieces of the coveskin on the outboard leading edge 
slats on the wings, which could result in skin separation or structural 
damage to the leading edge slats and consequent reduced controllability 
of the airplane.

Actions Since Issuance of Previous Rule

    In the preamble to AD 2000-19-08, the FAA indicated that the 
actions required by that AD were considered ``interim action'' and that 
further rulemaking action was being considered to revise the 
applicability of that AD to include additional airplanes. We now have 
determined that further rulemaking action is indeed necessary, and this 
proposed AD follows from that determination. Specifically, we have 
determined that the modification installed during production on Model 
777 series airplanes with line number 266 and subsequent does not 
prevent the cracking of the coveskin on the outboard leading edge 
slats; it only improves the fatigue life of those parts. Therefore, we 
find it necessary to mandate that the inspections required by the 
existing AD be accomplished on all Boeing Model 777 series airplanes, 
including those manufactured in the future.
    Also, since the issuance of AD 2000-19-08, we have received reports 
that certain kits supplied by the airplane manufacturer for the 
optional

[[Page 59388]]

modification described in that AD contained undersized seal inserts for 
slat numbers 4, 5, 10, and 11. The undersized seal inserts were made 
from raw material of an incorrect diameter. These undersized seal 
inserts would result in the slat being exposed to the same vibration of 
the coveskins, and the same consequent fatigue cracking and high 
fatigue loads, of an unmodified airplane. This condition, if not 
corrected, could result in skin separation or structural damage to the 
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 5, dated January 25, 2001. (AD 2000-19-08 refers 
to Boeing Alert Service Bulletin 777-57A0034, Revision 2, dated 
November 19, 1998; Revision 3, dated May 4, 2000; and Revision 4, dated 
July 20, 2000; as appropriate sources of service information for 
required actions.) The procedures in Revision 5 of the service bulletin 
are similar to those in prior issues of the service bulletin. However, 
the service bulletin differs from the prior issues in these ways:
     The effectivity listing of Revision 5 includes airplanes 
with line numbers 266 and subsequent. These airplanes are identified as 
``Group 3'' airplanes in the service bulletin. As explained previously, 
these airplanes are subject to the same repetitive inspections as other 
Model 777 series airplanes.
     For airplanes on which the optional modification has been 
accomplished in accordance with Revision 3 or 4 of the service 
bulletin, Part 5 of Revision 5 of the service bulletin describes 
procedures for a new one-time inspection for undersized seal inserts 
installed in the spanwise bulb seals on slat numbers 4, 5, 10, and 11. 
If undersized seal inserts are installed, Revision 5 specifies 
replacement of seal assemblies with new seal assemblies.
     Related to the new inspection in Part 5 of the service 
bulletin, the procedures for the optional modification in Part 4 of the 
service bulletin have been revised to include an inspection of the seal 
inserts to determine if they are the correct size.

Explanation of Changes to Requirements of AD 2000-19-08

    The applicability statement of AD 2000-19-08 identifies airplanes 
with line numbers 1 through 265 inclusive. However, Revision 5 of the 
service bulletin lists the airplane with line number 1 as a Group 3 
airplane because that airplane was modified during production like the 
other airplanes in Group 3. Therefore, line number 1 is not affected by 
the requirements of paragraph (a) of this proposed AD.
    Also, paragraph (b) of AD 2000-19-08 states, ``The corrective 
actions include stop drilling the crack and performing detailed visual 
inspections, slat adjustment checks, and replacement of the slats.'' A 
reference to repairing the crack was omitted from this description. 
Therefore, for clarification, the description of corrective actions in 
paragraph (b) of this AD has been revised to read, ``The corrective 
actions include stop drilling and repairing the crack * * *.''
    Paragraph (b) of AD 2000-19-08 stated an incorrect issue date 
(April 4, 2000) for Boeing Alert Service Bulletin 777-57A0034, Revision 
3, dated May 4, 2000. In the ``Restatement of Requirements of AD 2000-
19-08'' included in this proposed AD, paragraph (b) has been revised to 
refer to the correct date.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would supersede AD 2000-19-08 to continue to require 
repetitive detailed visual inspections to detect cracking of the 
coveskin on the outboard leading edge slats, and corrective actions, if 
necessary. The proposed AD also continues to provide for an optional 
modification that significantly increases the repetitive inspection 
interval. The proposed AD would expand the applicability of the 
existing AD by mandating the currently required inspections, and 
corrective actions, if necessary, for additional airplanes. Also, for 
airplanes on which the optional modification has been accomplished, the 
proposed AD would require a new one-time inspection for undersized seal 
inserts installed in the spanwise bulb seals on certain slats, and 
replacement of seal assemblies with new assemblies, if necessary. The 
actions would be required to be accomplished in accordance with 
Revision 5 of the service bulletin described previously, except as 
discussed below.

Differences Between Proposed Rule and Service Bulletin

    Operators should note that, while the service bulletin refers only 
to an ``inspection'' for undersized seal inserts, this proposed AD 
would require a ``detailed visual inspection.'' The FAA has determined 
that the procedures in the service bulletin should be described as a 
detailed visual inspection. Note 2 of this proposed AD defines this 
type of inspection.
    The service bulletin specifies that the manufacturer may be 
contacted for disposition of certain repair conditions. However, this 
proposed AD would require the repair of those conditions to be 
accomplished in accordance with a method approved by the FAA.

Cost Impact

    There are approximately 184 airplanes of the affected design in the 
worldwide fleet.
    The detailed visual inspection for cracking specified in this 
proposed rule is currently required by AD 2000-19-08, which is 
applicable to approximately 81 airplanes of U.S. registry. Those 
inspections take approximately 7 work hours per airplane to accomplish, 
at an average labor rate of $60 per work hour. Based on the figures 
discussed above, the cost impact of the current requirements of that AD 
on U.S. operators is estimated to be $34,020, or $420 per airplane, per 
inspection cycle.
    This proposed action would require accomplishment of the detailed 
visual inspection for cracking on approximately 33 additional airplanes 
of U.S. registry. Based on the figures discussed above, the new costs 
to U.S. operators that would be imposed by this AD are estimated to be 
$13,860.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the proposed requirements 
of this AD action, and that no operator would accomplish those actions 
in the future if this proposed AD were not adopted. The cost impact 
figures discussed in AD rulemaking actions represent only the time 
necessary to perform the specific actions actually required by the AD. 
These figures typically do not include incidental costs, such as the 
time required to gain access and close up, planning time, or time 
necessitated by other administrative actions.
    Should an operator be required to accomplish the proposed new one-
time inspection for undersized seal inserts, it would take 
approximately 2 work hours per airplane, at an average labor rate of 
$60 per work hour. Based on these figures, the cost impact of this new 
inspection is estimated to be $120 per airplane.

Regulatory Impact

    The regulations proposed herein would not have a substantial direct 
effect on the States, on the relationship

[[Page 59389]]

between the national Government and the States, or on the distribution 
of power and responsibilities among the various levels of government. 
Therefore, it is determined that this proposal would not have 
federalism implications under Executive Order 13132.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, will not have a significant economic impact, 
positive or negative, on a substantial number of small entities under 
the criteria of the Regulatory Flexibility Act. A copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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 removing amendment 39-11909 (65 FR 
57282, September 22, 2000), and by adding a new airworthiness directive 
(AD), to read as follows:

Boeing: Docket 2001-NM-35-AD. Supersedes AD 2000-19-08, Amendment 
39-11909.

    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 (h)(1) 
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 or missing pieces of the 
coveskin, or undersized seal inserts installed in the spanwise bulb 
seals, on the outboard leading edge slats on the 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:

Restatement of Requirements of AD 2000-19-08

Inspection

    (a) For airplanes having line numbers 2 through 265 inclusive: 
At the applicable time specified by paragraph (a)(1) or (a)(2) of 
this AD, perform detailed visual inspections to detect cracking of 
the coveskin 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; Revision 3, dated May 
4, 2000; Revision 4, dated July 20, 2000, or Revision 5, dated 
January 25, 2001. Repeat the inspections thereafter at intervals not 
to exceed 100 flight cycles or 400 flight hours, whichever occurs 
first.
    (1) For airplanes on which the repetitive inspections required 
by paragraph (a) of AD 99-04-19 HAVE been initiated prior to October 
10, 2000 (the effective date of AD 2000-19-08, amendment 39-11909): 
Inspect at the earlier of the times specified by paragraphs 
(a)(1)(i) and (a)(1)(ii) of this AD.
    (i) Within 350 flight cycles after the most recent inspection.
    (ii) At the later of the times specified by paragraphs 
(a)(1)(ii)(A) and (a)(1)(ii)(B) of this AD.
    (A) Within 100 flight cycles or 400 flight hours, whichever 
occurs first, after the most recent inspection.
    (B) Within 30 days after October 10, 2000.
    (2) For airplanes on which the repetitive inspections required 
by paragraph (a) of AD 99-04-19 have NOT been initiated prior to 
October 10, 2000: Inspect at the earlier of the times specified by 
paragraphs (a)(2)(i) and (a)(2)(ii) of this AD.
    (i) Prior to the accumulation of 500 total flight cycles.
    (ii) Prior to the accumulation of 2,000 total flight hours, or 
within 30 days after October 10, 2000, whichever occurs later.

    Note 2: For the purposes of this AD, a detailed visual 
inspection is defined as: ``An intensive visual examination of a 
specific structural area, system, installation, or assembly to 
detect damage, failure, or irregularity. Available lighting is 
normally supplemented with a direct source of good lighting at 
intensity deemed appropriate by the inspector. Inspection aids such 
as mirror, magnifying lenses, etc., may be used. Surface cleaning 
and elaborate access procedures may be required.''

Corrective Action

    (b) If any cracking is detected during any inspection required 
by paragraph (a) of this AD, prior to further flight, accomplish all 
applicable corrective actions specified by and in accordance with 
Boeing Alert Service Bulletin 777-57A0034, Revision 2, dated 
November 19, 1998; Revision 3, dated May 4, 2000; Revision 4, dated 
July 20, 2000; or Revision 5, dated January 25, 2001. The corrective 
actions include stop drilling and repairing the crack and performing 
detailed visual inspections, slat adjustment checks, and replacement 
of the slats. Where the alert service bulletin specifies to contact 
Boeing for appropriate Action Prior to further flight, repair in 
accordance with a method approved by the Manager, Seattle Aircraft 
Certification Office, FAA. For a repair method to be approved by the 
Manager, Seattle ACO, as required by this paragraph, the Manager's 
approval letter must specifically reference this AD. After October 
10, 2000, only Revision 4 or 5 of the alert service bulletin may be 
used.

Optional Modification

    (c) Accomplishment of the actions specified by paragraphs (c)(1) 
and (c)(2) of this AD extends the repetitive inspection interval 
specified by paragraph (a) of this AD to 8,000 flight cycles.
    (1) Install a seal insert into the spanwise bulb seals for the 
slats in accordance with Part 4 of Boeing Alert Service Bulletin 
777-57A0034, Revision 3, dated May 4, 2000; Revision 4, dated July 
20, 2000; or Revision 5, dated January 25, 2001.
    (2) Within 750 days or 4,000 flight cycles, whichever occurs 
first, after installing the seal insert as specified by paragraph 
(c)(1) of this AD: Perform a detailed visual inspection of the 
interior structure of the coveskin 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.

New Requirements of This AD

Repetitive Inspections (Certain Airplanes)

    (d) For airplanes having line numbers 1 and 266 and subsequent: 
Prior to the accumulation of 8,000 total flight cycles, or within 
500 flight cycles after the effective date of this AD, whichever 
occurs later, perform a detailed visual inspection to detect 
cracking of the coveskin 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 5, dated January 25, 2001. Repeat the 
inspection thereafter at intervals not to exceed 8,000 flight 
cycles.

Corrective Action

    (e) If any cracking is detected during any inspection required 
by paragraph (d) of this AD, prior to further flight, accomplish all 
applicable corrective actions specified by and in accordance with 
Boeing Alert Service Bulletin 777-57A0034, Revision 5, dated January 
25, 2001. The corrective actions include stop drilling and repairing 
the crack and performing detailed visual inspections, slat 
adjustment checks, and replacement of the slats. Where the alert 
service bulletin specifies to contact Boeing for appropriate action: 
Prior to further flight, repair in

[[Page 59390]]

accordance with a method approved by the Manager, Seattle ACO. For a 
repair method to be approved by the Manager, Seattle ACO, as 
required by this paragraph, the Manager's approval letter must 
specifically reference this AD.

One-Time Inspection--Undersized Seal Inserts

    (f) For airplanes on which the optional modification described 
in paragraph (c) of this AD was accomplished prior to the effective 
date of this AD in accordance with Part 4 of Boeing Alert Service 
Bulletin 777-57A0034, Revision 3, dated May 4, 2000; or Revision 4, 
dated July 20, 2000: Within 500 flight cycles after the effective 
date of this AD, do a one-time detailed visual inspection for 
undersized seal inserts installed in the spanwise bulb seals of slat 
numbers 4, 5, 10, and 11, in accordance with Part 5 of Boeing Alert 
Service Bulletin 777-57A0034, Revision 5, dated January 25, 2001.

    Note 3: An inspection accomplished prior to the effective date 
of this AD in accordance with Boeing Telegraphic Message M-7200-00-
02516, ``Incorrect Insert Part Numbers in SB 777-57A0034,'' dated 
October 13, 2000, is considered acceptable for compliance with 
paragraph (f) of this AD.

    (1) For any seal insert of the correct size as specified in 
Revision 5 of the service bulletin: No further action is required by 
this paragraph.
    (2) For any undersized seal insert as specified in Revision 5 of 
the service bulletin, or for any seal insert that cannot be 
conclusively determined to be of correct size: Prior to further 
flight, replace the existing seal assembly with a new seal assembly, 
in accordance with Revision 5 of the service bulletin.

Spares

    (g) As of the effective date of this AD, no one may install a 
seal insert into the spanwise bulb seals of slat numbers 4, 5, 10, 
and 11, unless it is inspected in accordance with Part 4 of Boeing 
Alert Service Bulletin 777-57A0034, Revision 5, dated January 25, 
2001, and found to be of correct size.

Alternative Methods of Compliance

    (h)(1) 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.
    (2) Alternative methods of compliance, approved previously in 
accordance with AD 99-04-19, amendment 39-11044, are approved as 
alternative methods of compliance with paragraph (b) of this AD.
    (3) Alternative methods of compliance, approved previously in 
accordance with AD 2000-19-08, amendment 39-11909, are approved as 
alternative methods of compliance with corresponding requirements of 
this AD.

    Note 4: 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

    (i) 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.

    Issued in Renton, Washington, on November 21, 2001.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-29600 Filed 11-27-01; 8:45 am]
BILLING CODE 4910-13-U