[Federal Register Volume 59, Number 2 (Tuesday, January 4, 1994)]
[Proposed Rules]
[Pages 265-266]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-23]


[[Page Unknown]]

[Federal Register: January 4, 1994]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 93-NM-174-AD]

 

Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of 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 action would require the 
inclusion of additional airplanes to the candidate fleet. This proposal 
is prompted by a recommendation from the Airworthiness Assurance Task 
Force, Model 747 Structures Working Group. The actions specified by the 
proposed AD are intended to ensure the continued structural integrity 
of the total Boeing Model 747 fleet.

DATES: Comments must be received by March 1, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 93-NM-174-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.
    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: 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:

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 notice may be changed in 
light of the comments received.
    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 93-NM-174-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-103, Attention: Rules 
Docket No. 93-NM-174-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On March 18, 1993, the FAA issued AD 93-06-01, Amendment 39-8526 
(58 FR 19571, April 15, 1993), applicable to certain Boeing Model 747 
series airplanes, 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 
structural re-evaluation by the manufacturer which identified 
additional structural elements where, if damage should occur, 
supplemental inspections may be required for timely detection. The 
requirements of that AD are intended to ensure the continued structural 
integrity of the total Boeing Model 747 fleet.
    Since the issuance of that AD, the FAA has reviewed and approved 
Boeing Document No. D6-35022, Volumes 1 and 2, ``Supplemental 
Structural Inspection Document (SSID) for Model 747 Airplanes,'' 
Revision E, dated June 17, 1993, that revises the effectivity by adding 
airplanes to the candidate fleet on which supplemental inspections that 
give no less than the required damage tolerance rating (DTR) for each 
Structural Significant Item (SSI) must be performed. This document also 
clarifies the selection criteria for candidate airplanes. The original 
Model 747-100 and -200 series airplanes in the candidate fleet were 
selected based on having accumulated 10,000 flight cycles by June 30, 
1983. Subsequently, selected high time airplanes were added to the 
candidate fleet to replace out-of-service airplanes. Incorporation of 
the inspections described in this document will ensure the continuing 
structural integrity of the total Boeing Model 747 fleet.
    Since the failure of an SSI can compromise the structural integrity 
of these airplanes, and since such conditions are likely to exist or 
develop on other Model 747 series airplanes, the proposed AD would 
supersede AD 93-06-01 to expand the applicability to require that the 
inspections identified in the Boeing document, described previously, be 
performed on the airplanes in the candidate fleet to provide no less 
than the required damage tolerance rating (DTR) for each Structural 
Significant Item (SSI) listed in Revision E of the SSID.
    Moreover, the FAA has identified eight additional airplanes that 
are not listed in Revision E of the Boeing Document, and that must be 
added to the candidate fleet to replace certain airplanes that were 
removed from the candidate fleet. Some of these newly identified 
airplanes were operated as short range (SR) airplanes and have now been 
converted to freighters. Therefore, the FAA has determined that these 
airplanes must be included in the SSID program, and that supplemental 
inspections must also be performed on these additional airplanes to 
ensure safety of the entire Boeing Model 747 fleet. The AD proposes to 
expand the applicability by adding these eight airplanes.
    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 would be affected by 
this proposed AD. Incorporation of the SSID program into an operator's 
maintenance program, as required by AD 93-06-01, and retained in this 
proposal, 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 costs, as required by AD 93-06-01, and 
retained in this proposal, 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 proposal, 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 proposal, 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 proposal 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 proposal, 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, 
would 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 regulations proposed herein would 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    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 14 
CFR part 39 of the Federal Aviation Regulations 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), to read as follows:

Boeing: 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.
    (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 FAR 
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 December 28, 1993.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-23 Filed 1-3-94; 8:45 am]
BILLING CODE 4910-13-P