[Federal Register Volume 65, Number 125 (Wednesday, June 28, 2000)]
[Proposed Rules]
[Pages 39828-39831]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-16358]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-326-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-400 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Boeing Model 747-400 
series airplanes. This proposal would require repetitive inspections to 
detect fatigue cracking of the longeron splice fittings at stringer 11 
on the left and right sides at body station 2598, and various follow-on 
actions. This action is necessary to detect and correct fatigue 
cracking of the longeron splice fittings and subsequent damage to 
adjacent structure. Such damage could result in the inability of the 
structure to carry horizontal stabilizer flight loads, and consequent 
reduced controllability of the horizontal stabilizer. This action is 
intended to address the identified unsafe condition.

DATES: Comments must be received by August 14, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-326-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 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: 
<a href="/cdn-cgi/l/email-protection#98a1b5f9f6f5b5f6e8eaf5fbf7f5f5fdf6ecd8fef9f9b6fff7ee"><span class="__cf_email__" data-cfemail="c9f0e4a8a7a4e4a7b9bba4aaa6a4a4aca7bd89afa8a8e7aea6bf">[email protected]</span></a>. Comments sent via fax or the Internet must 
contain ``Docket No. 99-NM-326-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, PO 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: Rick Kawaguchi, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-1153; 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

[[Page 39829]]

considered before taking action on the proposed rule. The proposals 
contained in this notice may be changed in light of the comments 
received.
    Submit comments using the following format:
    <bullet> 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.
    <bullet> For each issue, state what specific change to the proposed 
AD is being requested.
    <bullet> 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 notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 99-NM-326-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. 99-NM-326-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports indicating that fatigue cracking was 
detected on the longeron splice fittings at stringer 11 on certain 
Boeing Model 747-100, -200, -300, 747SR and 747SP series airplanes. On 
three airplanes with flight cycles ranging from 16,867 to 27,146, and 
with flight hours ranging from 30,198 to 62,783, the splice fitting 
cracks that were detected measured up to 1.5 inches long. The longeron 
splice fittings on Model 747-400 series airplanes affected by this 
proposal are identical to those on which the fatigue cracking was 
detected. Such fatigue cracking, and subsequent damage to adjacent 
structure, could result in the inability of the structure to carry 
horizontal stabilizer flight loads, and consequent reduced 
controllability of the horizontal stabilizer.

Related Rulemaking

    This proposed AD is related to AD 2000-10-23, amendment 39-11748 
(65 FR 34061, June 30, 2000), which is applicable to certain Boeing 
Model 747-100, -200, -300, 747SR, and 747SP series airplanes. That AD 
requires repetitive inspections to detect cracking of the longeron 
splice fittings at stringer 11, on the left and right sides at body 
station 2598, and replacement of any cracked fitting with a new 
fitting. This NPRM proposes similar actions for Boeing Model 747-400 
series airplanes.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-53A2419, dated December 17, 1998, which describes procedures for 
repetitive detailed visual inspections to detect cracking of the 
longeron splice fittings at stringer 11, on the left and right sides at 
body station 2598. If no cracking is detected, follow-on actions 
include rework of the fittings or replacement of the fittings with new 
fittings, and repetitive inspections to detect cracking. If any 
cracking is detected, the corrective action is to be accomplished prior 
to further flight. The corrective action includes replacement of all 
four longeron splice fittings on the affected side, and repetitive 
detailed visual inspections to detect cracking. Accomplishment of the 
actions specified in the alert service bulletin is intended to 
adequately address the identified unsafe condition.

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 require accomplishment of the actions specified in 
the alert service bulletin described previously, except as discussed 
below.

Differences Between Proposed Rule and Alert Service Bulletin

    Operators should note that, although the alert service bulletin 
specifies that the manufacturer may be contacted for disposition of 
certain repair or replacement conditions, this AD requires the repair 
or replacement of those conditions to be accomplished in accordance 
with a method approved by the FAA, or in accordance with data meeting 
the type certification basis of the airplane approved by a Boeing 
Company Designated Engineering Representative who has been authorized 
by the FAA to make such findings.
    Operators also should note that the alert service bulletin 
specifies that the corrective actions required by this proposed AD may 
be accomplished in accordance with ``an operator's equivalent 
procedure.'' However, this proposed AD requires that an ``operator's 
equivalent procedure'' may be used only in accordance with the 
procedures specified in the operator's maintenance manual.
    This proposed AD would mandate rework or replacement of all four 
longeron splice fittings on the applicable side of the airplane if any 
of the four fittings on that side are reworked or replaced. The alert 
service bulletin provides for that action as recommended.

Cost Impact

    There are approximately 490 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 59 airplanes of U.S. registry 
would be affected by this proposed AD.
    It would take approximately 2 work hours (1 hour per each side) per 
airplane to accomplish the proposed inspection, at an average labor 
rate of $60 per work hour. Based on these figures, the cost impact of 
the proposed inspection on U.S. operators is estimated to be $7,080, or 
$120 per airplane, per inspection cycle.
    It would take approximately 12 work hours (6 hours per each side) 
per airplane to accomplish the proposed rework or replacement, at an 
average labor rate of $60 per work hour. Required parts would cost 
between $731 and $7,906 per airplane. Based on these figures, the cost 
impact of the proposed rework or replacement on U.S. operators is 
estimated to be between $1,451 and $8,626 per airplane.
    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.

Regulatory Impact

    The regulations proposed herein would not have a substantial direct 
effect on the States, on the relationship between the national 
Government and the States, or on the distribution of

[[Page 39830]]

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 adding the following new 
airworthiness directive:

Boeing: Docket 99-NM-326-AD.

    Applicability: Model 747-400 series airplanes, as listed in 
Boeing Alert Service
    Bulletin 747-53A2419, dated December 17, 1998; 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 (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 fatigue cracking of the longeron splice 
fittings and subsequent damage to adjacent structure, which could 
result in the inability of the structure to carry horizontal 
stabilizer flight loads, and consequent reduced controllability of 
the horizontal stabilizer; accomplish the following:

Initial Detailed Visual Inspection

    (a) Perform a detailed visual inspection to detect cracking of 
the longeron fittings at stringer 11, on the left and right sides at 
body station 2598, at the later of the times specified in paragraphs 
(a)(1) and (a)(2) of this AD, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-53A2419, dated 
December 17, 1998.
    (1) Inspect prior to the accumulation of 17,000 total flight 
cycles or 63,000 total flight hours, whichever occurs first.
    (2) Inspect within 24 months after the effective date of this 
AD.

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


    Note 3: 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.''

Rework/Replacement/Repetitive Inspections

    (b) If no cracking is detected during the inspection required by 
paragraph (a) of this AD, accomplish the requirements of either 
paragraph (b)(1), (b)(2), or (b)(3) of this AD.
    (1) Prior to further flight, rework all four longeron splice 
fittings on the left and right sides at body station 2598, in 
accordance with Part 3 of the Accomplishment Instructions of Boeing 
Alert Service Bulletin 747-53A2419, dated December 17, 1998. Repeat 
the inspection required by paragraph (a) of this AD one time at the 
later of the times specified in paragraphs (b)(1)(i) and (b)(1)(ii) 
of this AD, and thereafter at intervals not to exceed 3,000 flight 
cycles or 18,000 flight hours, whichever occurs first.
    (i) For airplanes on which the rework is accomplished prior to 
the accumulation of 7,000 total flight cycles and prior to the 
accumulation of 25,000 total flight hours: Inspect within 20,000 
flight cycles or 72,000 flight hours after rework, whichever occurs 
first.
    (ii) For airplanes on which the rework is accomplished at or 
after the accumulation of 7,000 total flight cycles, or 25,000 total 
flight hours: Inspect within 10,000 flight cycles or 36,000 flight 
hours after rework, whichever occurs first.
    (2) Prior to further flight, replace all four longeron splice 
fittings on the left and right sides at body station 2598 with new 
fittings, in accordance with Part 2 of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-53A2419, dated 
December 17, 1998. Repeat the inspection required by paragraph (a) 
of this AD one time within 20,000 flight cycles or 72,000 flight 
hours after the replacement, whichever occurs first; and thereafter 
at intervals not to exceed 3,000 flight cycles or 18,000 flight 
hours, whichever occurs first.
    (3) Repeat the inspection required by paragraph (a) of this AD 
at intervals not to exceed 3,000 flight cycles or 18,000 flight 
hours, whichever occurs first.

Corrective Action/Repetitive Inspections

    (c) If any cracking is detected during any inspection required 
by paragraph (a) or (b)(3) of this AD, prior to further flight: 
Replace all four longeron splice fittings on the affected side in 
accordance with Part 2 of the Accomplishment Instructions of Boeing 
Alert Service Bulletin 747-53A2419, dated December 17, 1998. Repeat 
the inspection required by paragraph (a) of this AD one time within 
20,000 flight cycles or 72,000 flight hours after the replacement, 
whichever occurs first; and thereafter at intervals not to exceed 
3,000 flight cycles or 18,000 flight hours, whichever occurs first.
    (d) If any cracking is detected during any inspection required 
by paragraph (b)(1), (b)(2), or (c) of this AD, repair in accordance 
with a method approved by the Manager, Seattle Aircraft 
Certification Office (ACO), FAA, Transport Airplane Directorate; or 
in accordance with data meeting the type certification basis of the 
airplane approved by a Boeing Company Designated Engineering 
Representative (DER) who has been authorized by the Manager, Seattle 
ACO, to make such findings. For a repair method to be approved by 
the Manager, Seattle ACO, as required by this paragraph, the 
approval letter must specifically reference this AD.

    Note 4: There is no terminating action currently available for 
the inspections required by this AD.

Alternative Methods of Compliance

    (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 5: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permit

    (f) Special flight permits may be issued in accordance with 
Secs. 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.


[[Page 39831]]


    Issued in Renton, Washington, on June 22, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-16358 Filed 6-27-00; 8:45 am]
BILLING CODE 4910-13-U


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