[Federal Register Volume 59, Number 154 (Thursday, August 11, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-18454]


[[Page Unknown]]

[Federal Register: August 11, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 93-NM-174-AD; Amendment 39-8989; AD 94-15-18]

 

Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to certain Boeing Model 747 series airplanes, that 
currently requires that the FAA-approved maintenance inspection program 
include inspections which will give no less than the required damage 
tolerance rating (DTR) for each Structural Significant Item (SSI). This 
amendment requires the inclusion of additional airplanes to the 
candidate fleet. This amendment is prompted by a recommendation from 
the Airworthiness Assurance Working Group, Model 747 Structures Task 
Group. The actions specified by this AD are intended to ensure the 
continued structural integrity of the total Boeing Model 747 fleet.

DATES: Effective September 12, 1994.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of September 12, 1994.

ADDRESSES: 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 Federal 
Aviation Administration (FAA), Transport Airplane Directorate, Rules 
Docket, 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: Steven Fox, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle 
Aircraft Certification Office, 1601 Lind Avenue SW., Renton, Washington 
98055-4056; telephone (206) 227-2777; fax (206) 227-1181.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD 93-06-01, 
amendment 39-8526 (58 FR 19571, April 15, 1993), which is applicable to 
certain Boeing Model 747 series airplanes, was published in the Federal 
Register on January 4, 1994 (59 FR 265). The action proposed to require 
that the FAA-approved maintenance inspection program be revised to 
include inspections which will give no less than the required damage 
tolerance rating (DTR) for each Structural Significant Item (SSI). That 
action was prompted by a recommendation from the Airworthiness 
Assurance Working Group, Model 747 Structures Task Group (STG). The 
requirements of that AD are intended to ensure the continued structural 
integrity of the total Boeing Model 747 fleet.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    One commenter supports the proposed rule.
    Several commenters request that the selection of airplanes in the 
candidate fleet be determined by the STG, which is comprised of 
representatives from various operators, the FAA, and Boeing. The FAA 
does not concur. The FAA has determined that retired airplanes, hull 
losses, or parked airplanes that are in the current candidate fleet 
must be replaced with in-service airplanes to maintain the candidate 
fleet size of 117 in-service airplanes. In selecting replacement 
airplanes for the candidate fleet, the FAA evaluates, among other 
factors, age and service history of in-service airplanes. The FAA will 
continue to consider recommendations from the STG for replacement 
airplanes; however, the responsibility for determining the suitability 
of airplanes for the candidate fleet ultimately rests with the FAA.
    One commenter questions the validity for including Boeing Model 
747SR series airplanes in the Supplemental Structural Inspection 
Document (SSID) candidate fleet. This commenter states that the FAA's 
justification for including these airplanes was based upon the 
conversion of these airplanes from passenger operations to cargo 
operations, which the commenter alleges is incorrect. The commenter 
further states that the FAA needs to consider the inclusion of 
airplanes based upon maintenance requirements, especially airplanes 
that have been modified in accordance with supplemental type 
certificates (STC). The FAA does not concur. The FAA points out that it 
included certain Boeing Model 747SR series airplanes because these 
airplanes were no longer operated as Model 747SR series airplanes (at 
low gross weights and at reduced engine thrusts), not because they were 
converted from passenger operations to cargo operations. Since those 
airplanes are now operated similarly to other airplanes that are in the 
Boeing Model 747 SSID candidate fleet and that are operated as both 
freighter and passenger airplanes, the FAA has determined that they, 
too, should be included in the SSID candidate fleet. As noted above, 
the FAA considers many factors when selecting airplanes for inclusion 
into the candidate fleet, including age and service history of the 
airplane, which may be affected by modifications that were performed in 
accordance with STC's.
    Since AD 86-19-01 requires structural inspections and repairs or 
replacements on certain Model 747-100SR series airplanes, a number of 
commenters request that AD 86-19-01, Amendment 39-5395 (51 FR 29212, 
August 15, 1986), be revised to exclude Model 747SR series airplanes 
that are now included in this rulemaking action to avoid redundant 
requirements for inspection. One of these commenters requests that the 
requirement to inspect SSI's, required by AD 86-19-01, be exempt from 
the requirements of this AD. The FAA concurs. The FAA will, in a 
separate rulemaking action, revise AD 86-19-01 to exclude Model 747-
100SR series airplanes that have been included in this final rule.
    One commenter requests an extension in the compliance time until 
such time that a review of the damage tolerance rating (DTR) check 
forms has been completed and a revised SSID has been issued. The FAA 
does not concur. To extend the compliance time for this action would be 
inappropriate, since the FAA has determined that an unsafe condition 
exists and that inspections must be conducted to ensure continued 
safety. Additional rulemaking may be considered, however, once the DTR 
check forms have been reviewed and incorporated into the revised SSID.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule as proposed.
    There are approximately 128 Boeing Model 747 series airplanes of 
the affected design in the worldwide fleet. The FAA estimates that 87 
airplanes of U.S. registry and 8 U.S. operators will be affected by 
this AD. Incorporation of the SSID program into an operator's 
maintenance program, as required by AD 93-06-01, and retained in this 
AD, is estimated to necessitate 1,000 work hours (per operator) at an 
average labor rate of $55 per work hour. Based on these figures, the 
total cost to the 8 affected U.S. operators to incorporate the SSID 
program is estimated to be $440,000, or $55,000 per U.S. operator.
    The recurring inspections cost, as required by AD 93-06-01, and 
retained in this AD, is estimated to be 1,275 work hours per airplane 
at an average labor rate of $55 per work hour. Based on these figures, 
the annual recurring cost required by AD 93-06-01, and retained in this 
AD, is estimated to be $6,100,875 for the affected U.S. fleet, or 
$70,125 per airplane.
    Since no new operators have been added by this AD, there will be no 
new costs associated with incorporating the SSID program into an 
operator's maintenance program. Therefore, the future economic cost 
impact of this AD on U.S. operators is now only the cost of the 
recurring inspections for these additional airplanes.
    The number of required work hours for the recurring inspections in 
this AD, as indicated above, is presented as if the accomplishment of 
the actions were to be conducted as ``stand alone'' action. However, in 
actual practice, these actions, for the most part, will be accomplished 
coincidentally or in combination with normally scheduled airplane 
inspections and other maintenance program tasks. Therefore, the actual 
number of necessary additional work hours will be minimal in many 
instances. Additionally, any costs associated with special airplane 
scheduling will be minimal.
    The total cost impact figure discussed above is based on 
assumptions that no operator has yet accomplished any of the 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted.
    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.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it 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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-8526 (58 FR 
19571, April 15, 1993), and by adding a new airworthiness directive 
(AD), amendment 39-8989, to read as follows:

94-15-18 Boeing: Amendment 39-8989. Docket 93-NM-174-AD. Supersedes 
AD 93-06-01, Amendment 39-8526.

    Applicability: Model 747 series airplanes, as listed in Section 
3.0 of Boeing Document No. D6-35022, Volumes 1 and 2, ``Supplemental 
Structural Inspection Document (SSID) for Model 747 Airplanes,'' 
Revision E, dated June 17, 1993; and manufacturer's line numbers 42, 
174, 221, 231, 234, 239, 242, and 254; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To ensure the continued structural integrity of the total Boeing 
Model 747 fleet, accomplish the following:
    (a) For airplanes listed in Boeing Document No. D6-35022, 
Volumes I and II, ``Supplemental Structural Inspection Document 
(SSID),'' Revision D, dated February 1992: Within 12 months after 
May 17, 1993 (the effective date of AD 93-06-01, Amendment 39-8526), 
incorporate a revision into the FAA-approved maintenance inspection 
program which provides no less than the required Damage Tolerance 
Rating (DTR) for each Structural Significant Item (SSI) listed in 
Boeing Document No. D6-35022, Revision D, dated February 1992. (The 
required DTR value for each SSI is listed in the document.) The 
revision to the maintenance program shall include Sections 5.0 and 
6.0 of the SSID and shall be implemented in accordance with the 
procedures contained in those sections. Revision to the maintenance 
program shall be in accordance Revision D of the SSID, until 
Revision E of the SSID is incorporated into the FAA-approved 
maintenance inspection program in accordance with the requirements 
of paragraph (b) of this AD.
    (b) For airplanes listed in Boeing Document No. D6-35022, 
Volumes 1 and 2, ``Supplemental Structural Inspection Document 
(SSID) for Model 747 Airplanes,'' Revision E, dated June 17, 1993; 
and manufacturer's line numbers 42, 174, 221, 231, 234, 239, 242, 
and 254: Within 12 months after the effective date of this AD, 
replace the revision of the FAA-approved maintenance inspection 
program required by paragraph (a) of this AD with a revision that 
provides no less than the required DTR for each SSI listed in Boeing 
Document No. D6-35022, Volumes 1 and 2, ``Supplemental Structural 
Inspection Document (SSID) for Model 747 Airplanes,'' Revision E, 
dated June 17, 1993. (The required DTR value for each SSI is listed 
in the document.) The revision to the maintenance program shall 
include Sections 5.0 and 6.0 of the SSID and shall be implemented in 
accordance with the procedures contained in those sections.
    (c) Cracked structure must be repaired, prior to further flight, 
in accordance with an FAA-approved method.
    (d) 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: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (e) 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.
    (f) The incorporation of the revision shall be done in 
accordance with Boeing Document No. D6-35022, Volumes 1 and 2, 
``Supplemental Structural Inspection Document (SSID) for Model 747 
Airplanes,'' Revision E, dated June 17, 1993, which contains the 
following list of effective pages: 

------------------------------------------------------------------------
                                                       Revision letter  
                     Page No.                          shown on page    
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List of Active Pages-.............................  E                   
Pages 1 through 21.1 .............................                      
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    (Note: The issue date is indicated only on the title page of 
Volume 1.) 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.

    (g) This amendment becomes effective on September 12, 1994.

    Issued in Renton, Washington, on July 22, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-18454 Filed 8-10-94; 8:45 am]
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