[Federal Register Volume 66, Number 35 (Wednesday, February 21, 2001)]
[Proposed Rules]
[Pages 10974-10976]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-4219]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-251-AD]
RIN 2120-AA64


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 adoption of a new airworthiness 
directive (AD) that is applicable to all Boeing Model 747 series 
airplanes. This proposal would require repetitive high frequency eddy 
current inspections to find cracking of the bulkhead frame support at 
body station 2598 under the hinge support fittings of the horizontal 
stabilizer, and repair if cracking is found. This action is necessary 
to find and fix fatigue cracking in the frame support, which could 
result in inability of the structure to carry horizontal stabilizer 
flight loads and reduced controllability of the horizontal stabilizer. 
This action is intended to address the identified unsafe condition.

DATES: Comments must be received by April 9, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-251-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: 
<a href="/cdn-cgi/l/email-protection#b78e9ad6d9da9ad9c7c5dad4d8dadad2d9c3f7d1d6d699d0d8c1"><span class="__cf_email__" data-cfemail="645d49050a09490a141609070b0909010a10240205054a030b12">[email protected]</span></a>. Comments sent via fax or the Internet must 
contain ``Docket No. 2000-NM-251-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: Rick Kawaguchi, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, 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 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:
    <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

[[Page 10975]]

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 2000-NM-251-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. 2000-NM-251-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received a report indicating that a fatigue crack (1.25 
inches in length) was found on the bulkhead frame support under the 
hinge support fittings of the horizontal stabilizer at body station 
(BS) 2598 on a Model 747-200F series airplane. The airplane had 
accumulated approximately 13,488 total flight cycles and 58,697 total 
flight hours at the time the crack was found. Such cracking in the 
frame support, if not found and fixed, could result in inability of the 
structure to carry horizontal stabilizer flight loads and reduced 
controllability of the horizontal stabilizer.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-53A2449, dated June 8, 2000. The service bulletin describes 
procedures for repetitive open-hole high frequency eddy current 
inspections to find cracking of the bulkhead frame support located on 
the left and right sides at BS 2598 under the hinge support fittings of 
the horizontal stabilizer. If cracking is found, the service bulletin 
specifies to contact Boeing for repair instructions.

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 service bulletin described previously, except as discussed below.

Difference Between Service Bulletin and This Proposed AD

    The service bulletin specifies that the manufacturer must be 
contacted for repair of certain conditions, but this proposal would 
require the repair of those conditions to be accomplished per a method 
approved by the FAA, or per 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. For a method to be approved, the approval letter must 
specifically reference this AD.

Cost Impact

    There are approximately 1,314 airplanes of the affected design in 
the worldwide fleet. The FAA estimates that 258 airplanes of U.S. 
registry would be affected by this proposed AD, that it would take 
approximately 8 work hours (4 work hours per side) per airplane to 
accomplish the proposed inspections, and that the average labor rate is 
$60 per work hour. Based on these figures, the cost impact of the 
proposed AD on U.S. operators is estimated to be $123,840, or $480 per 
airplane, per inspection cycle.
    The cost impact figure discussed above is 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 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 2000-NM-251-AD.

    Applicability: Model 747 series airplanes, as listed in Boeing 
Alert Service Bulletin 747-53A2449, dated June 8, 2000, 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 find and fix fatigue cracking in the bulkhead frame support 
at body station (BS) 2598 under the hinge support fittings of the 
horizontal stabilizer, which could result in inability of the 
structure to carry horizontal stabilizer flight loads and reduced 
controllability of the horizontal stabilizer, accomplish the 
following:

Repetitive High Frequency Eddy Current (HFEC) Inspections

    (a) Before the accumulation of 10,000 total flight cycles, or 
within 1,000 flight cycles after the effective date of this AD, 
whichever occurs later: Do an open-hole HFEC

[[Page 10976]]

inspection to find cracking of the bulkhead frame support under the 
hinge support fittings of the horizontal stabilizer on the left and 
right sides at BS 2598, per Figure 2 of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-53A2449, dated 
June 8, 2000. Repeat the inspection after that at intervals not to 
exceed 3,000 flight cycles.

Repair

    (b) If any cracking is found during any inspection required by 
paragraph (a) of this AD, before further flight, repair per a method 
approved by the Manager, Seattle Aircraft Certification Office 
(ACO), FAA; or per data meeting the type certification basis of the 
airplane approved by a Boeing Company Designated Engineering 
Representative 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.

Alternative Methods of Compliance

    (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.

Special Flight Permit

    (d) 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.

    Issued in Renton, Washington, on February 13, 2001.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-4219 Filed 2-20-01; 8:45 am]
BILLING CODE 4910-13-U


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