[Federal Register Volume 72, Number 161 (Tuesday, August 21, 2007)]
[Rules and Regulations]
[Pages 46545-46549]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-16106]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-24952; Directorate Identifier 2006-NM-107-AD; 
Amendment 39-15157; AD 2007-16-18]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 767 Airplanes

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

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
Boeing Model 767 airplanes. This AD requires repetitive detailed 
inspections of the wire bundles, power drive unit (PDU) wiring, and 
wire attaching hardware, supports, and sleeving located in the forward 
and aft lower lobe cargo compartments, and corrective actions as 
necessary. This AD results from a fire in the forward lower lobe cargo 
compartment found shortly after airplane arrival. We are issuing this 
AD to detect and correct damage to wires in the forward and aft lower 
lobe cargo compartments, which could result in a potential short 
circuit and consequent fire in the forward and aft lower lobe cargo 
compartments.

DATES: This AD becomes effective September 25, 2007.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in the AD as of September 25, 
2007.

ADDRESSES: You may examine the AD docket on the Internet at http://dms.dot.gov or in person at the U.S. Department of Transportation, 
Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 
New Jersey Avenue, SE., Washington, DC.
    Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for service information identified in this AD.

FOR FURTHER INFORMATION CONTACT: Elias Natsiopoulos, Aerospace 
Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-
4056; telephone (425) 917-6478; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Examining the Docket

    You may examine the airworthiness directive (AD) docket on the 
Internet at http://dms.dot.gov or in person at the Docket Operations 
office between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Operations office (telephone (800) 647-5527) is 
located on the ground floor of the West Building at the street address 
stated in the ADDRESSES section.

Discussion

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to include an AD that would apply to all Boeing Model 767 
airplanes.

[[Page 46546]]

That NPRM was published in the Federal Register on June 6, 2006 (71 FR 
32489). That NPRM proposed to require repetitive detailed inspections 
of the wire bundles, power drive unit (PDU) wiring, and wire attaching 
hardware, supports, and sleeving located in the forward and aft lower 
lobe cargo compartments, and corrective actions as necessary.

Actions Since NPRM Was Issued

    Since we issued the NPRM, Boeing has published Service Bulletin 
767-25-0376, Revision 1, dated February 9, 2007, for Model 767-200, -
300, and -300F series airplanes; and Service Bulletin 767-25-0377, 
Revision 1, dated February 9, 2007, for Model 767-400ER series 
airplanes. In the NPRM, we referred to the original issue of Boeing 
Service Bulletin 767-25-0376 and Boeing Service Bulletin 767-25-0377, 
both dated November 17, 2005, as appropriate sources of service 
information for accomplishing the repetitive inspections and corrective 
actions. The procedures in Revision 1 of the service bulletins are 
essentially the same as the procedures in the original issue of the 
service bulletins, except that the revised service bulletins replace 
all references to Task 25-52-00, ``Cargo Compartment--Cleaning/
Painting,'' of the Boeing 767 Airplane Maintenance Manual (AMM) with 
references to Task 20-60-02, ``Cleaning to Remove Combustible Material 
Around Wiring.'' Therefore, we have revised paragraph (f) of this AD to 
refer to Revision 1 of the service bulletins as appropriate sources of 
service information for accomplishing the actions required by this AD. 
We have also added a new paragraph (g) to this AD allowing credit for 
actions accomplished before the effective date of this AD in accordance 
with the original issue of the service bulletins.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comments received.

Support for the NPRM

    Air Transport Association (ATA), American Airlines, and United 
Airlines agree with the intent of the NPRM.

Request To Clarify the Cleaning Procedure

    ATA, on behalf of its member United Airlines, states that Boeing 
Service Bulletin 767-25-0376, dated November 17, 2005, specifies 
cleaning the cargo compartments using Task 25-52-00-701 of the Boeing 
767 AMM. United Airlines further states that Task 25-52-00-701 
specifies cleaning the entire compartment using solvents while removing 
insulation. United Airlines, therefore, requests the AMM task be 
clarified, since it believes that this task does not address the intent 
of the NPRM.
    We agree, since the intent of the NPRM was to propose cleaning only 
wiring, wiring components, and the small area contacting the wiring in 
order to detect and correct damage that could be concealed by debris. 
As we mentioned previously, Boeing has issued Revision 1 to Service 
Bulletin 767-25-0376, which refers instead to Task 20-60-02, ``Cleaning 
to Remove Combustible Material Around Wiring,'' of the Boeing 767 AMM. 
Paragraph (f) of this AD refers to Revision 1 of the service bulletin 
as the appropriate source of service information for Model 767-200, -
300, and -300F series airplanes. No additional change to this AD is 
necessary in this regard.

Request To Revise Summary

    Boeing requests that we revise the Summary section of the NPRM to 
specify that PDU stands for ``power drive unit.'' Boeing states that 
PDU was incorrectly defined as ``power display unit'' in the NPRM. We 
agree and have revised this AD as requested.

Request To Increase the Estimated Work Hours

    Boeing requests that we increase the estimated work hours from 6 
hours to 20 hours for an airplane with a partial cargo compartment 
floor and to 22 hours for an airplane with a full cargo compartment 
floor. Boeing states that these numbers were provided in Boeing Service 
Bulletins 767-25-0376 and 767-25-0377, both dated November 17, 2005.
    Although we agree with revising the estimated work hours found in 
the Costs of Compliance section of this AD, we disagree with using the 
estimate provided by the commenter. 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. The original issue and Revision 1 of Boeing 
Service Bulletins 767-25-0376 and 767-25-0377 state that the 
examination of the forward lower lobe cargo compartment takes 3 hours 
and the examination of the aft lower lobe cargo compartment takes 3 
hours. The service bulletins also state that cleaning the forward and 
aft lobe cargo compartments takes 2 hours each. However, the NPRM did 
not include time to accomplish the cleaning. Therefore, we have updated 
the estimated work hours to 10 hours per airplane in this AD and have 
updated the estimated costs accordingly.

Request To Clarify the Unsafe Condition

    Boeing requests we revise the Discussion section of the NPRM to 
clarify that crushed and chafed PDU power supply cables ``along with 
other wire and wire support damage,'' if not corrected, could result in 
a potential short circuit and consequent fire in the forward and aft 
lower lobe cargo compartments. Boeing states that the statements in the 
Discussion section of the NPRM could lead a reader to believe that the 
fire occurred at the location of the crushed and chafed PDU power 
supply cables. Boeing further states that the fire occurred in the 
bilge approximately two feet below the PDUs, at a location where the 
airplane wiring is installed in close proximity to the insulation 
blankets.
    We agree that the statement as written in the NPRM could lead a 
reader to believe that inspection and corrective actions should only be 
limited to the PDU power supply cables. The intent of the NPRM was to 
propose inspecting all wiring in the forward and aft lower lobe cargo 
compartment, not just the wiring associated with the PDU. Any wire or 
wiring components found to be damaged must be repaired to adequately 
address the unsafe condition of this AD. However, we have not revised 
this AD since the Discussion section of the NPRM is not carried over 
into a final rule.

Request To Reduce Compliance Time and Add Terminating Action

    ATA, on behalf of its member United Airlines, requests that the FAA 
and Boeing pursue a more conclusive method of resolving the damage to 
wires in the cargo compartments. United Airlines states that the 
actions proposed in the NPRM are of limited value and do not address 
the root cause of the problem; the service bulletins provide procedures 
for cleaning and routinely inspecting the subject wire bundles, but do 
not provide any preventive or terminating action. United Airlines 
further states that even though it implemented the requirements of this 
AD into its maintenance program two years ago, it has found three 
additional occurrences on airplanes that have been cleaned and 
inspected. United Airlines states that the industry would benefit if 
the airplane manufacturer could lead a collaborative effort to (1) 
implement a

[[Page 46547]]

way to prevent cargo debris from falling onto and into the high-voltage 
wiring runs and (2) address failures that have occurred under the 
clamps where debris was not the issue, including those failures that 
have occurred soon after cleaning and inspection. United Airlines, 
therefore, requests that we revise the NPRM to reduce the inspection 
and cleaning interval to 18 months, and that Boeing develop a 
terminating action.
    We appreciate the commenter's concern to have the inspection and 
cleaning done more frequently. In developing an appropriate compliance 
time for this action, we considered the urgency associated with the 
subject unsafe condition, the practical aspect of accomplishing the 
required inspections within a period of time that corresponds to the 
normal scheduled maintenance for most affected operators, and the 
recommendations of the manufacturer. In light of these items, we have 
determined that the compliance time proposed in the NPRM is 
appropriate. Operators are always permitted to accomplish the 
requirements of an AD earlier than the specified compliance time. We 
have not changed this AD in this regard.
    We agree with United Airline's suggestion for a collaborative 
effort to investigate the feasibility and implementation of preventive 
actions because preventive actions will more effectively address the 
root cause of the wiring damage. The FAA and Boeing have considered the 
following actions, and their feasibility, in preventing debris from 
falling onto wiring:
     Installing the full complement of floor panels.
     Installing conduit or sleeving over wire bundles.
     Rerouting the wire bundles to locations that are less 
exposed to debris.
     Performing good maintenance practices.
    The full complement of floor panels is currently available as an 
option to operators, if they choose to have them installed. However, 
even if the full complement of floor panels is installed, the wiring is 
still susceptible to damage when the panels are removed for maintenance 
or other actions.
    Conduit or sleeving over wire bundles is not a viable option, since 
the conduit/sleeving would be exposed to step-ons and dropped tools, 
which may crush the conduit/sleeving and damage the wires inside. 
Further, the conduit/sleeving would conceal any damage, making it less 
likely for the maintenance crew to detect the damage.
    Rerouting the wire bundles to locations that are less exposed to 
debris is not feasible or recommended because it would be a major 
change. The modification would require structural changes to provide 
bundle supports, as well as require lengthening the wire bundles.
    Good maintenance practices would substantially reduce the exposure 
of wiring to falling debris and minimize the occurrence of wire damage.
    At this time, we have determined that repetitive inspections and 
cleaning will adequately address the unsafe condition. To delay this 
action would be inappropriate, since we have determined that an unsafe 
condition exists and that inspections must be conducted to ensure 
continued safety. We might consider additional rulemaking, however, if 
a preventive modification is developed by the airplane manufacturer. 
Operators may also request, under the provisions of paragraph (h) of 
this AD, an alternative method of compliance (AMOC) if sufficient data 
are submitted to substantiate that such a design change would provide 
an acceptable level of safety. Therefore, we have not revised this AD 
in this regard.
    We also agree that the cable clamps should be inspected, since 
history has shown that the wires under the cable clamps can be damaged 
not only by falling debris but also by other conditions. The 
commenter's statement regarding clamp failures implies that the NPRM 
and service bulletins only address wiring damage caused by falling 
debris. However, the procedures in the service bulletins, which are 
mandated by this AD, specify to inspect all wiring components to detect 
and correct damage caused by any environmental condition, not just 
falling debris. The inspection applies to all wire cable clamps, 
regardless of location. Further, experience has shown that wiring 
damage is often caused by poor maintenance practices. The corrective 
actions for the cable clamps are part of routine maintenance per the 
Boeing 767 Standard Wiring Practices Manual, which is referenced in the 
applicable service bulletin. We have not revised this AD in this 
regard.

Request To Revise Discussion

    Boeing requests that we revise the Discussion section of the NPRM 
to state that the source of the fire was near the bottom of the bilge 
below the 13L and 14L PDUs. As justification, Boeing states that this 
is the location where the airplane wiring for the suspect PDUs is 
installed. Boeing also requests that we revise the Discussion section 
of the NPRM to state that investigation revealed that the flammable 
debris had accumulated ``(in the bilge)'' below the 13L and 14L PDUs.
    Although we agree that a portion of the suspect PDU wiring is 
routed near the bottom of the bilge, none of the reports specified the 
exact point of initiation of the fires. Further, the Boeing service 
bulletins state that: ``It was found that flammable debris collected 
below the 13L and 14L PDUs; but the source of ignition was not 
positively identified.'' The NPRM correctly identified the location of 
the accumulated debris as being in the area below the 13L and 14L PDUs, 
which includes the bilge. Therefore, no change to this AD is necessary 
in this regard.

Request To Revise the Applicability

    ABX Air states that the PDUs and associated wiring have been 
removed on 24 of its airplanes in accordance with a supplemental type 
certificate. ABX Air asserts these airplanes are not susceptible to the 
unsafe condition identified in the NPRM. Therefore, ABX Air requests 
that we revise the applicability to as follows:

    This AD applies to all Boeing Model 767-200, -300, -300F, and -
400ER series airplanes equipped with a powered cargo handling system 
in the forward or aft lower lobe compartment, certificated in any 
category.

    We disagree with limiting the applicability of the AD as proposed 
by the commenter. To adequately address the unsafe condition, this AD 
requires an inspection of all wires and wiring components in the 
forward and aft lower cargo compartments, not just the PDU and 
associated wiring. If the PDU, associated wiring, and all other wires 
and wiring components have also been removed on the commenter's 
airplanes, then no further action is required by this AD. However, the 
operator must still apply for an AMOC for relief from the requirements 
of this AD. Under the provisions of paragraph (h) of this AD, we may 
consider requests for approval of an AMOC if sufficient data are 
submitted to substantiate that such a design change would provide an 
acceptable level of safety. We have not changed this AD in this regard.

Request To Extend Compliance Time

    ATA, on behalf of its member American Airlines, requests that we 
extend the compliance time for the repetitive inspection to 74 months 
or 30,000 flight hours, whichever occurs first. In the NPRM, we 
proposed a repetitive interval of 72 months or 24,000 flight hours, 
whichever occurs first. American Airlines states that it schedules main 
base visits (MBVs) every 18 months for Model 767 airplanes. It

[[Page 46548]]

also uses flex scheduling, which allows for scheduling an extra 10 
percent calendar time depending on the history of the airplane. 
American Airlines states the NPRM proposes the repetitive inspection 
every fourth MBV, and that it accomplishes the fourth MBV at a maximum 
of 4 times 18 plus 10 percent, which is equal to 73.8 months. American 
Airlines further states that it can fly an airplane almost 27,800 
flight hours between fourth MBVs, which includes the extra 10 percent 
due to flex scheduling. American Airlines asserts that the compliance 
time it proposes will keep airplanes safe for the flying public. 
American Airlines states that the FAA can avoid the cost of processing 
a request for an AMOC if the compliance time is extended as it 
proposes.
    We disagree with extending the compliance time. In developing an 
appropriate compliance time for this action, we considered the urgency 
associated with the subject unsafe condition, the practical aspect of 
accomplishing the required inspections within a period of time that 
corresponds to the normal scheduled maintenance for most affected 
operators, and the recommendations of the manufacturer. In light of 
these items, we have determined that the compliance time proposed in 
the NPRM is appropriate. However, according to the provisions of 
paragraph (h) of this AD, we might approve requests to adjust the 
compliance time if the request includes data that prove that the new 
compliance time would provide an acceptable level of safety. We have 
not changed this AD in this regard.

Request To Revise Costs of Compliance

    American Airlines estimates that the cost of complying with the 
NPRM will require approximately 6 work hours per airplane at a cost of 
$563, every six years. We infer the commenter would like us to revise 
the estimated costs in this AD.
    We disagree with revising the estimated costs for this AD. In 
determining those costs we used the estimated work hours provided in 
the Boeing service bulletins. As stated previously, we have updated the 
estimated work hours in this AD to reflect a higher cost for 
accomplishing the cleaning and inspections required by this AD. 
Therefore, we have not changed this AD in this regard.

Clarification of AMOC Paragraph

    We have revised this action to clarify the appropriate procedure 
for notifying the principal inspector before using any approved AMOC on 
any airplane to which the AMOC applies.

Conclusion

    We have carefully reviewed the available data, including the 
comments received, and determined that air safety and the public 
interest require adopting the AD with the changes described previously. 
We have determined that these changes will neither increase the 
economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

    There are about 857 airplanes of the affected design in the 
worldwide fleet. This AD affects about 374 airplanes of U.S. registry. 
The required inspections take about 10 work hours per airplane, at an 
average labor rate of $80 per work hour. Based on these figures, the 
estimated cost of the AD for U.S. operators is $299,200, or $800 per 
airplane, per inspection cycle.

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 AD will not have federalism 
implications under Executive Order 13132. This AD will 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 this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866;
    (2) Is not a ``significant rule'' under 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 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, Incorporation by 
reference, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The Federal Aviation Administration (FAA) amends Sec.  39.13 by 
adding the following new airworthiness directive (AD):

2007-16-18 Boeing: Amendment 39-15157. Docket No. FAA-2006-24952; 
Directorate Identifier 2006-NM-107-AD.

Effective Date

    (a) This AD becomes effective September 25, 2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to all Model 767-200, -300, -300F, and -
400ER series airplanes, certificated in any category.

Unsafe Condition

    (d) This AD results from a fire in the forward lower lobe cargo 
compartment found shortly after airplane arrival. We are issuing 
this AD to detect and correct damage to wires in the forward and aft 
lower lobe cargo compartments, which could result in a potential 
short circuit and consequent fire in the forward and aft lower lobe 
cargo compartments.

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.

Repetitive Inspections and Corrective Actions if Applicable

    (f) Within 36 months after the effective date of this AD, do 
detailed inspections for damage to the wire bundles, power drive 
unit wiring, and wire attaching hardware, supports, and sleeving 
located in the forward and aft lower lobe cargo compartments; and do 
all applicable corrective actions before

[[Page 46549]]

further flight after the inspections; by accomplishing all of the 
actions specified in the Accomplishment Instructions of Boeing 
Service Bulletin 767-25-0376, Revision 1, dated February 9, 2007 
(for Model 767-200, -300, and -300F series airplanes); or Boeing 
Service Bulletin 767-25-0377, Revision 1, dated February 9, 2007 
(for Model 767-400ER series airplanes); as applicable. Repeat the 
inspections thereafter at intervals not to exceed 24,000 flight 
hours or 72 months, whichever occurs first.

Credit for Actions Accomplished According to Previous Issues of Service 
Bulletins

    (g) Actions accomplished before the effective date of this AD in 
accordance with Boeing Service Bulletin 767-25-0376, dated November 
17, 2005 (for Model 767-200, -300, and -300F series airplanes); or 
Boeing Service Bulletin 767-25-0377, dated November 17, 2005 (for 
Model 767-400ER series airplanes); are considered acceptable for 
compliance with the corresponding actions specified in paragraph (f) 
of this AD.

Alternative Methods of Compliance (AMOCs)

    (h)(1) The Manager, Seattle Aircraft Certification Office, FAA, 
has the authority to approve AMOCs for this AD, if requested in 
accordance with the procedures found in 14 CFR 39.19.
    (2) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Before using any approved AMOC on any airplane to which the AMOC 
applies, notify your appropriate principal inspector (PI) in the FAA 
Flight Standards District Office (FSDO), or lacking a PI, your local 
FSDO.

Material Incorporated by Reference

    (i) You must use Boeing Service Bulletin 767-25-0376, Revision 
1, dated February 9, 2007; or Boeing Service Bulletin 767-25-0377, 
Revision 1, dated February 9, 2007; as applicable; to perform the 
actions that are required by this AD, unless the AD specifies 
otherwise. The Director of the Federal Register approved the 
incorporation by reference of these documents in accordance with 5 
U.S.C. 552(a) and 1 CFR part 51. Contact Boeing Commercial 
Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for a copy 
of this service information. You may review copies at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington; or at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Renton, Washington, on August 2, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E7-16106 Filed 8-20-07; 8:45 am]
BILLING CODE 4910-13-P