[Federal Register Volume 67, Number 118 (Wednesday, June 19, 2002)]
[Proposed Rules]
[Pages 41640-41642]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-15368]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
 
 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
 ========================================================================
 

  Federal Register / Vol. 67, No. 118 / Wednesday, June 19, 2002 / 
Proposed Rules  

[[Page 41640]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-30-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 777 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to all Boeing Model 777 series 
airplanes. This proposal would require repetitive inspections for 
cracking of the floor beam structure located at body station 246; and 
repair, if necessary. This action is necessary to find and fix such 
cracking, which could extend and sever the floor beam, resulting in 
rapid depressurization of the airplane and consequent collapse of the 
floor structure. This action is intended to address the identified 
unsafe condition.

DATES: Comments must be received by August 5, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2001-NM-30-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: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2001-NM-30-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: Suzanne Masterson, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2772; 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:
     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.
     For each issue, state what specific change to the proposed 
AD is being requested.
     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 action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2001-NM-30-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. 2001-NM-30-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received numerous reports of fatigue cracking of the 
floor beam structure located at body station (BS) 246 on several Boeing 
Model 777 series airplanes. Investigation revealed that the fatigue is 
caused by high bending stresses in the forward and aft directions of 
the BS 246 floor beam during flight. The high stress is due to the 
temperature difference between the fuselage skin and the floor 
structure, which results in contraction of the fuselage skin and 
subsequent cracking of the floor structure. Additionally, cracked 
stiffeners and mid-chord cracking of the left and/or right body line 
(BL) 38.5 were found. Several web cracks were also found at left and 
right BL 32.5. Such cracking could extend and sever the floor beam, 
resulting in rapid depressurization of the airplane and consequent 
collapse of the floor structure.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Service Bulletin 777-53-
0031, dated October 26, 2000, which describes procedures for a detailed 
inspection for cracking of the floor beam structure located at BS 246. 
The inspection includes the floor beam clips, stiffeners, webs, and 
chords. The service bulletin also describes procedures for a low 
frequency eddy current (LFEC) inspection for cracking of the upper 
flange of the mid-chord at left and right BL 38.5. As an alternative to 
the LFEC inspection, the service bulletin allows for a detailed 
inspection of those areas. The alternative inspection necessitates 
removal of certain equipment and floor panels installed on the aft side 
of the BS 246 floor beam for access. If cracking is found, the service 
bulletin describes procedures for repair, as specified in the Boeing 
Model 777 Structural Repair

[[Page 41641]]

Manual. The service bulletin also specifies obtaining repair data from 
Boeing for certain cracking. Accomplishment of the actions specified in 
the 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 service bulletin described previously, except as discussed below.

Difference Between This Proposed AD and the Service Bulletin

    Although the service bulletin specifies that the manufacturer may 
be contacted for disposition of certain repairs/inspection procedures, 
this proposed AD would require such repairs/inspection procedures 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 
Manager, Seattle Aircraft Certification Office, to make such findings.

Interim Action

    This is considered to be interim action. The manufacturer has 
advised that it currently is developing a modification to address the 
unsafe condition that will reduce or eliminate the need for the 
requirement imposed by this proposed AD. Once this modification is 
developed, approved, and available, the FAA may consider additional 
rulemaking.

Cost Impact

    There are approximately 184 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 81 airplanes of U.S. registry 
would be affected by this proposed AD, that it would take approximately 
1 work hour 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 inspections proposed by this AD on U.S. 
operators is estimated to be $4,860, or $60 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 2001-NM-30-AD.

    Applicability: All Model 777 series airplanes, 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 cracking of the floor beam structure located at 
body station (BS) 246, which could extend and sever the floor beam, 
resulting in rapid depressurization of the airplane and consequent 
collapse of the floor structure, accomplish the following:

Repetitive Inspections

    (a) Within 2,500 flight cycles or 5,000 flight hours after the 
effective date of this AD, whichever is first: Do the inspections 
for cracking of the floor beam structure located at BS 246 as 
specified in paragraphs (a)(1) and (a)(2) of this AD, per Boeing 
Service Bulletin 777-53-0031, dated October 26, 2000. Repeat the 
inspections every 2,500 flight cycles or 5,000 flight hours, 
whichever is first.
    (1) Do a detailed inspection for cracking of the floor beam 
structure (including floor beam clips, stiffeners, webs, and chords) 
located at BS 246.
    (2) Do a low frequency eddy current (LFEC) inspection for 
cracking of the upper flange of the mid-chord at left and right body 
lines 38.5: As an alternative to the LFEC inspection a detailed 
inspection of this area may be done, provided that removal of 
certain equipment and floor panels installed on the aft side of the 
BS 246 floor beam is done to obtain access.

    Note 2: For the purposes of this AD, a detailed 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.''

Repair

    (b) If any crack is found during any inspection per paragraph 
(a) of this AD: Before further flight, repair per Boeing Service 
Bulletin 777-53-0031, dated October 26, 2000; except where the 
service bulletin specifies to contact Boeing for disposition of 
certain repairs, 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 as required by this paragraph,

[[Page 41642]]

the approval must specifically reference this AD.

    Note 3: There is no terminating action currently available for 
the repetitive inspections required by 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 4: 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 
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.

    Issued in Renton, Washington, on June 12, 2002.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-15368 Filed 6-18-02; 8:45 am]
BILLING CODE 4910-13-P