[Federal Register Volume 71, Number 147 (Tuesday, August 1, 2006)]
[Proposed Rules]
[Pages 43390-43392]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-12302]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-25470; Directorate Identifier 2006-NM-090-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-400 Series Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede an existing airworthiness 
directive (AD) that applies to certain Boeing Model 747-400 series 
airplanes. The existing AD currently requires replacement of the 
decompression panels that are located in the smoke barrier between the 
passenger and main deck cargo compartment with new panels of an 
improved design. This proposed AD would require modification of the 
decompression panels on the smoke barrier in the main deck cargo 
compartment or replacement of the smoke barrier with an improved smoke 
barrier, as applicable. This proposed AD would also require repetitive 
inspections of the decompression (vent) panels on the smoke barrier and 
corrective actions if necessary. This proposed AD also adds airplanes 
to the applicability. This proposed AD results from reports of 
decompression panels on the smoke barrier opening in flight and on the 
ground without a decompression event. We are proposing this AD to 
prevent inadvertent opening or tearing of decompression panels, which 
could result in degraded cargo fire detection and suppression 
capability, smoke penetration into an occupied compartment, and an 
uncontrolled cargo fire, if a fire occurs in the main deck cargo 
compartment.

DATES: We must receive comments on this proposed AD by September 15, 
2006.

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.
     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.
    Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for service information identified in this 
proposed AD.

FOR FURTHER INFORMATION CONTACT: Susan Letcher, Aerospace Engineer, 
Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98057-3356; telephone (425) 917-6474; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to submit any relevant written data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed in the ADDRESSES section. Include the docket number ``Docket No. 
FAA-2006-25470; Directorate Identifier 2006-NM-090-AD'' at the 
beginning 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 received 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 Web site, 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 may review the DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or visit 
http://dms.dot.gov.

Examining the Docket

    You may 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

[[Page 43391]]

(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 Docket Management 
System receives them.

Discussion

    On November 14, 1996, we issued AD 96-24-03, amendment 39-9829 (61 
FR 59319, November 22, 1996), for certain Boeing Model 747-400 
``combi'' series airplanes. That AD requires replacing the 
decompression panels located in the smoke barrier between the passenger 
and main deck cargo compartments with new panels of an improved design. 
That AD resulted from reports indicating that normal pressurization 
cycles are causing premature tearing or opening of these decompression 
panels. We issued that AD to prevent increased airflow in the cargo 
compartment caused by the tearing or opening of these panels; this 
condition, if not corrected, could result in delayed fire detection and 
reduced effectiveness of the cargo compartment fire suppression system.

Actions Since Existing AD Was Issued

    Since we issued AD 96-24-03, operators have reported that 
decompression panels on the smoke barrier in the main deck cargo 
compartment are opening in flight and on the ground without a 
decompression event, on Boeing Model 747-400 series airplanes. We have 
determined that the modification required by AD 96-24-03 has not been 
effective in preventing inadvertent opening or tearing of decompression 
panels on the smoke barrier. This condition, if not corrected, could 
result in degraded cargo fire detection and suppression capability, 
smoke penetration into an occupied compartment, and an uncontrolled 
cargo fire, if a fire occurs in the main deck cargo compartment.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 747-25A3353, dated 
December 9, 2004. The service bulletin describes procedures for either 
modifying the decompression panels on the smoke barrier in the main 
deck cargo compartment, or replacing the smoke barrier with an improved 
smoke barrier, depending on the airplane configuration. The 
modification, if required, includes the following actions:
     Replacing the existing decompression panels with new, 
improved decompression (vent) panels.
     Replacing the forward frames with new, improved forward 
frame assemblies.
     For certain airplanes, replacing spring clips with new 
spring clips.
     For certain airplanes, replacing snap brackets with new 
spring clips and removing chain assemblies.
     Installing aft frame angles.
    The service bulletin also describes procedures for inspecting the 
decompression (vent) panels of the smoke barrier for changes from their 
installed condition and accomplishing corrective actions as necessary. 
The corrective actions include restoring vent panels to their installed 
condition and replacing any damaged components with new components.
    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 develop on other airplanes of the 
same type design. For this reason, we are proposing this AD, which 
would supersede AD 96-24-03. The proposed AD would require 
accomplishing the actions specified in the service bulletin described 
previously.

Clarification of Inspection Terminology

    The ``inspection'' specified in the service bulletin is referred to 
as a ``general visual inspection'' in the proposed AD. We have included 
the definition for a general visual inspection in a note in the 
proposed AD.

Explanation of Change to Applicability

    We have revised the applicability of the proposed AD to identify 
model designations as published in the most recent type certificate 
data sheet for the affected models. The proposed AD does not use the 
term, ``combi'' airplanes. We have also added airplanes to the 
applicability of this proposed AD.

Costs of Compliance

    There are about 63 airplanes of the affected design in the 
worldwide fleet. The following table provides the estimated costs, at 
an average labor rate of $80 per hour, for U.S. operators to comply 
with the proposed AD. The estimated work hours and cost of parts for 
the proposed modification in the table below depends on the 
configuration of an airplane.

                                                 Estimated Costs
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                                                                             Number of  U.S.-
           Action              Work         Parts        Cost per airplane      registered         Fleet cost
                               hours                                            airplanes
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Modification (new proposed     16-17    $12,064-$15,362    $13,344-$16,722                  2    $26,688-$33,444
 action)....................
Replacement (new proposed          4             48,647             48,967                  2             97,934
 action)....................
Inspection (new proposed           2               None                160                  2                320
 action)....................
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Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
subtitle VII, part A, subpart III, section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

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:

[[Page 43392]]

    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 and placed it in the AD docket. 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 Federal Aviation Administration (FAA) amends Sec.  39.13 by 
removing amendment 39-9829 (61 FR 59319, November 22, 1996) and adding 
the following new airworthiness directive (AD):
Boeing: Docket No. FAA-2006-25470; Directorate Identifier 2006-NM-
090-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by September 
15, 2006.

Affected ADs

    (b) This AD supersedes AD 96-24-03.

Applicability

    (c) This AD applies to Boeing Model 747-400 series airplanes, 
certificated in any category, as identified in Boeing Alert Service 
Bulletin 747-25A3353, dated December 9, 2004.

Unsafe Condition

    (d) This AD results from reports of decompression panels on the 
smoke barrier opening in flight and on the ground without a 
decompression event. We are issuing this AD to prevent inadvertent 
opening or tearing of decompression panels, which could result in 
degraded cargo fire detection and suppression capability, smoke 
penetration into an occupied compartment, and an uncontrolled cargo 
fire, if a fire occurs in the main deck cargo compartment.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

New Requirements of This AD

Modification or Replacement, as Applicable

    (f) Within 48 months after the effective date of this AD: Modify 
the decompression panels on the smoke barrier or replace the smoke 
barrier with an improved smoke barrier, by accomplishing all of the 
actions specified in Work Package 1 of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-25A3353, dated 
December 9, 2004, as applicable.

Repetitive Inspection

    (g) Within 20 months or 6,000 flight hours after accomplishing 
paragraph (f) of this AD, whichever occurs first: Do a general 
visual inspection of the decompression (vent) panels on the smoke 
barrier for any changes from their installed condition, and do all 
corrective actions before further flight after the inspection, by 
accomplishing all of the actions specified in Work Package 2 of the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
25A3353, dated December 9, 2004, as applicable. Repeat the 
inspection thereafter at intervals not to exceed 20 months or 6,000 
flight hours, whichever occurs first.


    Note 1: For the purposes of this AD, a general visual inspection 
is: ``A visual examination of an interior or exterior area, 
installation, or assembly to detect obvious damage, failure, or 
irregularity. This level of inspection is made from within touching 
distance unless otherwise specified. A mirror may be necessary to 
ensure visual access to all surfaces in the inspection area. This 
level of inspection is made under normally available lighting 
conditions such as daylight, hangar lighting, flashlight, or 
droplight and may require removal or opening of access panels or 
doors. Stands, ladders, or platforms may be required to gain 
proximity to the area being checked.''

Alternative Methods of Compliance (AMOCs)

    (h)(1) The Manager, Seattle Aircraft Certification Office, 
Transport Airplane Directorate, FAA, has the authority to approve 
AMOCs for this AD, if requested in accordance with the procedures 
found in 14 CFR 39.19.
    (2) Before using any AMOC approved in accordance with Sec.  
39.19 on any airplane to which the AMOC applies, notify the 
appropriate principal inspector in the FAA Flight Standards 
Certificate Holding District Office.

    Issued in Renton, Washington, on July 21, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E6-12302 Filed 7-31-06; 8:45 am]
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