Airworthiness Directives; Boeing Model 747 Series Airplanes

[Federal Register Volume 63, Number 148 (Monday, August 3, 1998)]
[Rules and Regulations]
[Pages 41184-41186]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-20679]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-210-AD; Amendment 39-10689; AD 98-16-13]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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

SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to certain Boeing Model 747 series airplanes. This action 
requires a one-time inspection for missing fasteners of the splice 
fitting of the forward inner chord of the Body Station (BS) 2598 
bulkhead; and corrective actions, if necessary. This amendment is 
prompted by a report that fasteners were missing from the splice 
fitting of the forward inner chord. The actions specified in this AD 
are intended to prevent accelerated fatigue cracking of the inner 
chords of the BS 2598 bulkhead, which could result in inability of the 
structure to carry horizontal stabilizer flight loads, and consequent 
reduced controllability of the airplane.

DATES: Effective August 18, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of August 18, 1998.
    Comments for inclusion in the Rules Docket must be received on or 
before October 2, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-210-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

[[Page 41185]]

the Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.

FOR FURTHER INFORMATION CONTACT: Bob Breneman, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2776; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: The FAA has received a report indicating 
that fasteners were missing from the splice fitting of the forward 
inner chord of the Body Station (BS) 2598 bulkhead on a Boeing Model 
747 series airplane. The fasteners missing from the splice fitting 
resulted in accelerated initiation and propagation of fatigue cracking 
of both the forward and aft inner chords of the BS 2598 bulkhead. A 
0.2-inch crack was found in the forward inner chord, and a 3.0-inch 
horizontal crack and a 1.0-inch vertical crack were found in the aft 
inner chord. Such fatigue cracking, if not corrected, could result in 
inability of the structure to carry horizontal stabilizer flight loads, 
and consequent reduced controllability of the airplane.
    As a result of the report of missing fasteners, Boeing requested 
that operators perform inspections on a limited number of delivered 
airplanes. Sixteen airplanes were inspected, including ten that had 
been delivered at approximately the same time as the airplane on which 
cracks were found. The fasteners were found to be installed on all 16 
of those airplanes. However, Boeing has not been able to provide 
justification to limit the inspection for missing fasteners to a 
specific group of airplanes, so this AD requires an inspection for 
missing fasteners on all Boeing Model 747 series airplanes that have 
been delivered.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-53A2423, dated June 11, 1998, which describes procedures for a one-
time visual inspection for missing fasteners of the splice fitting of 
the forward inner chord of the BS 2598 bulkhead; and corrective 
actions, if any fasteners are missing. The corrective actions include 
performing a detailed visual inspection and a high frequency eddy 
current inspection for cracking of the forward and aft inner chords of 
the BS 2598 bulkhead, on the left and right sides of the airplane; 
repair, if necessary; and installation of the fasteners.

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 prevent accelerated fatigue cracking of the inner 
chords of the BS 2598 bulkhead, which could result in inability of the 
structure to carry horizontal stabilizer flight loads, 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. This AD also requires 
that operators report results of inspection findings (findings of 
missing fasteners only) to the FAA.

Interim Action

    This is considered to be interim action. There have been other 
reports of fatigue cracking of the inner chords of the BS 2598 
bulkhead, as well as cracking of repair angles that were installed to 
correct cracks that were detected previously in the inner chords of the 
bulkhead. The FAA is currently considering additional rulemaking to 
further address the unsafe condition of fatigue cracking in the inner 
chords of the BS 2598 bulkhead. However, the planned compliance time 
for the corrective actions is sufficiently long so that notice and 
opportunity for prior public comment will be practicable.

Differences Between This Rule and Alert Service Bulletin

    Operators should note that the statement of effectivity in the 
alert service bulletin does not include the Boeing Model 747 series 
airplane having line position 1155. That airplane is currently in 
storage and has not been delivered. Boeing is under contract to 
accomplish any required inspections prior to delivery of the airplane. 
Therefore, the applicability statement of this AD includes this 
airplane.
    Operators also should note that, although the alert service 
bulletin specifies that the manufacturer may be contacted for 
disposition of certain repair conditions, this AD requires the repair 
of those conditions to be accomplished in accordance with Boeing 747 
Structural Repair Manual (SRM) 53-10-04, Figure 72; or Boeing 747SP SRM 
53-19-02, Figure 41; as applicable; or in accordance with a method 
approved by the FAA.

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 98-NM-210-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,

[[Page 41186]]

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:

98-16-13  Boeing: Amendment 39-10689. Docket 98-NM-210-AD.

    Applicability: Model 747 series airplanes, line positions 1 
through 1157; 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 (c) 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 prevent accelerated fatigue cracking of the inner chords of 
the Body Station (BS) 2598 bulkhead, which could result in inability 
of the structure to carry horizontal stabilizer flight loads, and 
consequent reduced controllability of the airplane; accomplish the 
following:
    (a) Prior to the accumulation of 8,000 total flight cycles, or 
within 90 days after the effective date of this AD, whichever occurs 
later, perform a one-time visual inspection for missing fasteners of 
the splice fitting of the forward inner chord of the BS 2598 
bulkhead, on the left and right sides of the airplane, in accordance 
with Boeing Alert Service Bulletin 747-53A2423, dated June 11, 1998.
    (1) If all fasteners are present, no further action is required 
by this AD.
    (2) If any fastener is missing, prior to further flight, 
accomplish a detailed visual inspection and a high frequency eddy 
current inspection to detect cracking of the forward and aft inner 
chords of the BS 2598 bulkhead, on the left and right sides of the 
airplane; in accordance with the alert service bulletin.
    (i) If no cracking is detected, prior to further flight, install 
the fasteners, in accordance with the alert service bulletin.
    (ii) If any cracking is detected, prior to further flight, 
repair the cracking and install the fasteners, in accordance with 
Boeing 747 Structural Repair Manual (SRM) 53-10-04, Figure 72, or 
Boeing 747SP SRM 53-19-02, Figure 41; as applicable; or repair in 
accordance with a method approved by the Manager, Seattle Aircraft 
Certification Office (ACO), FAA, Transport Airplane Directorate.
    (b) Within 10 days after accomplishing the inspection required 
by paragraph (a) of this AD, submit a report of the inspection 
results (findings of missing fasteners only) to the Manager, Seattle 
Manufacturing Inspection District Office, FAA, Transport Airplane 
Directorate, 2500 East Valley Road, suite C-2, Renton, Washington 
98055-4056; fax (425) 227-1181. Information collection requirements 
contained in this regulation have been approved by the Office of 
Management and Budget (OMB) under the provisions of the Paperwork 
Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been 
assigned OMB Control Number 2120-0056.
    (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 2: 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) Except as provided by paragraph (a)(2)(ii) of this AD, the 
actions shall be done in accordance with Boeing Alert Service 
Bulletin 747-53A2423, dated June 11, 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 August 18, 1998.

    Issued in Renton, Washington, on July 27, 1998.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-20679 Filed 7-31-98; 8:45 am]
BILLING CODE 4910-13-U

The complete text was extracted from the official GovInfo HTML edition for this publication. Acquired 2026-10-09T04:59:54.598105+00:00. Text extraction preserves the recorded source wording; it does not determine current requirements.

Open the captured official edition

Source SHA-256

c9609dccbc57f398880205c807639cad19666e370edfa2d1f7bc7ffff2f15e17

Text SHA-256

517b018ade5a215f78fd109c8d4911706cbdb60e52dd4ac67b4f4c2653e80560