[Federal Register Volume 69, Number 158 (Tuesday, August 17, 2004)]
[Proposed Rules]
[Pages 51015-51017]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-18745]


 ========================================================================
 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. 69, No. 158 / Tuesday, August 17, 2004 / 
Proposed Rules  

[[Page 51015]]



DEPARTMENT OF TRANSPORTATION (DOT)

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-18876; Directorate Identifier 2003-NM-254-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 757-200 and -200PF Series 
Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain Boeing Model 757-200 and -200PF series airplanes. This 
proposed AD would require repetitive inspections and audible tap tests 
of the upper and lower skins of the trailing edge wedges on certain 
slats, and related investigative and corrective actions if necessary. 
This proposed AD also provides an optional terminating action for the 
repetitive inspections and audible tap tests. This proposed AD is 
prompted by a report of damage to the No. 4 leading edge slat. We are 
proposing this AD to prevent delamination of the leading edge slats, 
possible loss of pieces of the trailing edge wedge assembly during 
flight, reduction of the reduced maneuver and stall margins, and 
consequent reduced controllability of the airplane.

DATES: We must receive comments on this proposed AD by October 1, 2004.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility, U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, room PL-401, 
Washington, DC 20590.
     By fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact 
Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-
2207.
    You can examine the contents of this AD docket on the Internet at 
http://dms.dot.gov, or at the Docket Management Facility, U.S. 
Department of Transportation, 400 Seventh Street, SW., room PL-401, on 
the plaza level of the Nassif Building, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Dennis Stremick, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
917-6450; fax (425) 914-6590.

SUPPLEMENTARY INFORMATION: 

Docket Management System (DMS)

    The FAA has implemented new procedures for maintaining AD dockets 
electronically. As of May 17, 2004, new AD actions are posted on DMS 
and assigned a docket number. We track each action and assign a 
corresponding directorate identifier. The DMS AD docket number is in 
the form ``Docket No. FAA-2004-99999.'' The Transport Airplane 
Directorate identifier is in the form ``Directorate Identifier 2004-NM-
999-AD.'' Each DMS AD docket also lists the directorate identifier 
(``Old Docket Number'') as a cross-reference for searching purposes.

Comments Invited

    We invite you to submit any written relevant data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2004-18876; 
Directorate Identifier 2003-NM-254-AD'' in the subject line of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed AD. We will 
consider all comments submitted by the closing date and may amend the 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this proposed AD. Using the search function of 
that website, anyone can find and read the comments in any of our 
dockets, including the name of the individual who sent the comment (or 
signed the comment on behalf of an association, business, labor union, 
etc.). You can review DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
can visit http://dms.dot.gov.
    We are reviewing the writing style we currently use in regulatory 
documents. We are interested in your comments on whether the style of 
this document is clear, and your suggestions to improve the clarity of 
our communications that affect you. You can get more information about 
plain language at http://www.faa.gov/language and http://www.plainlanguage.gov.

Examining the Docket

    You can examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level of the Nassif Building at the DOT 
street address stated in the ADDRESSES section. Comments will be 
available in the AD docket shortly after the DMS receives them.

Discussion

    We have received a report of damage to the No. 4 leading edge slat 
on a Boeing Model 757-200 series airplane. The affected airplane had 
54,000 total flight hours and 24,000 total flight cycles. Investigation 
revealed that a large piece of the trailing edge wedge broke away from 
the slat during flight. The crew was not aware that the piece had 
broken away until a post-flight walk around inspection. Further 
investigation revealed that during the assembly of the affected 
trailing edge wedge, BMS 5-104 adhesive was used to bond the skins to 
the honeycomb core material. Analysis

[[Page 51016]]

showed that moisture entered the internal structure of the wedge 
assembly, resulting in a decrease in the strength of the trailing edge 
wedge skin-to-core bond and corrosion of the aluminum honeycomb core. 
This condition eventually caused an area of the skin to delaminate from 
the honeycomb core material. The intensity of the flight loads on the 
affected airplane was sufficient to cause pieces of the skin to break 
away during flight. This condition, if not corrected, could result in 
reduced maneuver and stall margins, and consequent reduced 
controllability of the airplane.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 757-57A0063, dated 
June 26, 2003. The alert service bulletin describes procedures for a 
detailed inspection and an audible tap test of the upper and lower 
skins of the trailing edge wedge on slats No. 2 through No. 4 inclusive 
and No. 7 through No. 9 inclusive, for evidence of damage and cracking 
on the trailing edge wedge assembly, and related investigative and 
corrective actions. Evidence of damage to the wedge assembly skin 
includes cracking in the skin; delamination of the skin and the chord, 
the doublers, and the honeycomb core; separation between those 
components; or bulges in the skin or areas where the skin has broken 
off from the wedge. Evidence of damage to the inboard and outboard ends 
of the wedge assembly includes cracking in the sealant and end potting, 
and pieces of end potting that have broken off from the wedge.
    If there is an indication of delamination during the audible tap 
test, the related investigative action is doing the ``Bondline 
Delamination Inspection in Honeycomb Structure'' described in the 
Boeing 757 Nondestructive Test Manual.
    The corrective actions include repairing affected trailing edge 
wedge assemblies, or replacing the trailing edge wedge assemblies with 
new, improved wedge assemblies. The service bulletin states that 
replacement of trailing edge wedge assemblies with new, improved 
trailing edge wedge assemblies eliminates the need for the repetitive 
detailed inspection and audible tap test.
    Accomplishing the actions specified in the service information is 
intended to adequately address the unsafe condition.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other airplanes 
of this same type design. Therefore, we are proposing this AD, which 
would require repetitive inspections and audible tap tests of the upper 
and lower skins of the trailing edge wedges on certain slats, and 
related investigative and corrective actions if necessary. The proposed 
AD would require you to use the service information described 
previously to perform these actions. The proposed AD provides an 
optional terminating action for the repetitive inspections and audible 
tap tests.

Costs of Compliance

    This proposed AD would affect about 139 airplanes worldwide. The 
following table provides the estimated costs for U.S. operators to 
comply with this proposed AD.

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                       Number  of
                                               Average                    Cost per        U.S.-
           Action              Work hours    labor rate       Parts       airplane     registered    Fleet cost
                                              per hour                                  airplanes
----------------------------------------------------------------------------------------------------------------
Inspection/ test, per               \1\ 6           $65          None      \2\ $390            97   \2\ $37,830
 inspection cycle...........
----------------------------------------------------------------------------------------------------------------
\1\ One work hour per slat, six slats per airplane.
\2\ Per inspection/test cycle.

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD 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.
    For the reasons discussed above, I certify that the 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. 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD. See the ADDRESSES section for a location 
to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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. The FAA amends Sec.  39.13 by adding the following new 
airworthiness directive (AD):

Boeing: Docket No. FAA-2004-18876; Directorate Identifier 2003-NM-
254-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this AD action by October 1, 2004.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 737-200 and -200PF series 
airplanes listed in Boeing Alert Service Bulletin 757-57A0063, dated 
June 26, 2003; certificated in any category.

Unsafe Condition

    (d) This AD was prompted by a report of damage to the No. 4 
leading edge slat. We are issuing this AD to prevent delamination of 
the leading edge slats, possible loss of pieces of the trailing edge 
wedge assembly during flight, reduction of the reduced maneuver and 
stall margins, and consequent reduced controllability of the 
airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within

[[Page 51017]]

the compliance times specified, unless the actions have already been 
done.

Repetitive Inspections and Tests

    (f) Within 18 months after the effective date of this AD: Do a 
detailed inspection and an audible tap test of the upper and lower 
skins of the trailing edge wedges on slats No. 2 through No. 4 
inclusive and No. 7 through No. 9 inclusive, for evidence of damage 
or cracking, in accordance with the Accomplishment Instructions of 
Boeing Alert Service Bulletin 757-57A0063, dated June 26, 2003. 
Repeat the detailed inspection and audible tap test thereafter at 
intervals not to exceed 18 months.

    Note 1: For the purposes of this AD, a detailed inspection is: 
``An intensive examination of a specific item, installation, or 
assembly to detect damage, failure, or irregularity. Available 
lighting is normally supplemented with a direct source of good 
lighting at an intensity deemed appropriate. Inspection aids such as 
mirror, magnifying lenses, etc., may be necessary. Surface cleaning 
and elaborate procedures may be required.''

Related Investigative and Corrective Actions

    (g) If any damage or cracking is found during any inspection or 
audible tap test required by paragraph (a) of this AD: Before 
further flight, do the related investigative action, if applicable, 
and replace the affected part with a new trailing edge wedge 
assembly or repair the affected part, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin 757-
57A0063, dated June 26, 2003. Accomplishing the replacement 
terminates the repetitive inspections and audible tap tests required 
by paragraph (f) of this AD for that wedge assembly only.

Parts Installation

    (h) As of the effective date of this AD, no trailing edge wedge 
assembly having a part number listed in the ``Existing Part Number'' 
column of the table in paragraph 2.C.3. of Boeing Alert Service 
Bulletin 757-57A0063, dated June 26, 2003, can be installed on any 
airplane unless it has been inspected, tested, and any necessary 
corrective actions accomplished in accordance with this AD.

Optional Terminating Action

    (i) Replacing all trailing edge wedge assemblies with new, 
improved wedge assemblies in accordance with Part III of the 
Accomplishment Instructions of Boeing Alert Service Bulletin 757-
57A0063, dated June 26, 2003, terminates the requirements of this 
AD.

Alternative Methods of Compliance (AMOCs)

    (j)(1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested in 
accordance with the procedures found in 14 CFR 39.19.
    (2) An AMOC that provides an acceptable level of safety may be 
used for any repair required by this AD, if it is approved by a 
Boeing Company Designated Engineering Representative who has been 
authorized by the Manager, Seattle ACO, to make those findings. For 
a repair method to be approved, the approval must specifically refer 
to this AD.

    Issued in Renton, Washington, on August 9, 2004.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-18745 Filed 8-16-04; 8:45 am]
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