
[Federal Register: September 8, 2008 (Volume 73, Number 174)]
[Rules and Regulations]               
[Page 51903-51906]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr08se08-2]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-0356; Directorate Identifier 2008-NM-042-AD; 
Amendment 39-15661; AD 2008-18-04]
RIN 2120-AA64

 
Airworthiness Directives; Bombardier Model DHC-8-400 Series 
Airplanes

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

ACTION: Final rule.

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SUMMARY: The FAA is superseding an existing airworthiness directive 
(AD), which applies to certain Bombardier Model DHC-8-400 series 
airplanes. That AD currently requires inspecting all barrel nuts to 
determine if the barrel nuts have a certain marking, inspecting 
affected bolts to determine if the bolts are pre-loaded correctly, and 
replacing all hardware if the pre-load is incorrect. For airplanes on 
which the pre-load is correct, the existing AD requires doing 
repetitive visual inspections for cracking of the barrel nuts and 
cradles and replacing all hardware for all cracked barrel nuts. The 
existing AD also requires replacing all hardware for certain affected 
barrel nuts that do not have cracking, which would end the repetitive 
inspections for those airplanes. The existing AD also provides an 
optional replacement for all affected barrel nuts. This new AD requires 
replacing all affected barrel nuts and applying a certain compound to 
the affected barrel nuts and bolts. This AD results from reports of 
cracking in the barrel nuts at the four primary front spar wing-to-
fuselage attachment joints. We are issuing this AD to detect and 
correct cracking of the barrel nuts at the wing front spar wing-to-
fuselage joints, which could result in reduced structural integrity of 
the wing-to-fuselage attachments and consequent detachment of the wing.

DATES: This AD becomes effective October 14, 2008.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of October 14, 
2008.
    On February 13, 2008 (73 FR 8187, February 13, 2008), the Director 
of the Federal Register approved the incorporation by reference of 
Bombardier Alert Service Bulletin A84-57-19, Revision A, dated February 
6, 2008.

ADDRESSES: For service information identified in this AD, contact 
Bombardier, Inc., Bombardier Regional Aircraft Division, 123 Garratt 
Boulevard, Downsview, Ontario M3K 1Y5, Canada.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://
www.regulations.gov; or in person at the Docket Management Facility 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this AD, the regulatory evaluation, 
any comments received, and other information. The address for the 
Docket Office (telephone 800-647-5527) is the Document Management 
Facility, U.S. Department of Transportation, Docket Operations, M-30, 
West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Pong Lee, Aerospace Engineer, Airframe 
and Propulsion Branch, ANE-171, FAA, New York Aircraft Certification 
Office, 1600 Stewart Avenue, Suite 410, Westbury, New York 11590; 
telephone (516) 228-7324; fax (516) 794-5531.

SUPPLEMENTARY INFORMATION:

Discussion

    The FAA issued a supplemental notice of proposed rulemaking (NPRM) 
to amend 14 CFR part 39 to include an AD that supersedes AD 2008-04-02, 
amendment 39-15374 (73 FR 8187, February 13, 2008). The existing AD 
applies to certain Bombardier Model DHC-8-400 series airplanes. That 
supplemental NPRM was published in the Federal Register on June 26, 
2008 (73 FR 36285). That supplemental NPRM proposed to continue to 
require inspecting all barrel nuts to determine if the barrel nuts have 
a certain marking, inspecting affected bolts to determine if the bolts 
are pre-loaded correctly, and replacing all hardware if the pre-load is 
incorrect. For airplanes on which the pre-load is correct, that 
supplemental NPRM also proposed to continue to require doing repetitive 
visual inspections for cracking of the barrel nuts and cradles and 
replacing all hardware for all cracked barrel nuts. That supplemental 
NPRM also proposed to continue to require replacing all hardware for 
certain affected barrel nuts that do not have cracking, which would end 
the repetitive inspections for those airplanes. In addition, that 
supplemental NPRM also proposed to continue to provide an optional 
replacement for all affected barrel nuts. Finally, that supplemental 
NPRM also proposed to require replacing all affected barrel nuts and 
applying a certain compound to the affected barrel nuts and bolts.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. No comments have been received on the NPRM or 
on the determination of the cost to the public.

Conclusion

    We have carefully reviewed the available data and determined that 
air

[[Page 51904]]

safety and the public interest require adopting the AD as proposed.

Costs of Compliance

    This AD affects about 48 airplanes of U.S. registry.
    The actions that are required by AD 2008-04-02 and retained in this 
AD take about 3 work hours per airplane, at an average labor rate of 
$80 per work hour. Based on these figures, the estimated cost of the 
currently required actions is $11,520, or $240 per airplane, per 
inspection cycle.
    Replacement of the hardware of a barrel nut, if required, takes 
about 12 work hours per airplane, at an average labor rate of $80 per 
work hour. Required parts cost about $800 per barrel nut. Based on 
these figures, we estimate the cost of a replacement to be $1,760 per 
barrel nut.
    Application of the compound, if required, takes about 4 work hours 
per airplane, at an average labor rate of $80 per work hour. Based on 
these figures, we estimate the cost of a replacement to be $320 per 
application.

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 
removing amendment 39-15374 (73 FR 8187, February 13, 2008) and by 
adding the following new airworthiness directive (AD):

2008-18-04 Bombardier, Inc. (Formerly de Havilland, Inc.): Amendment 
39-15661. Docket No. FAA-2008-0356; Directorate Identifier 2008-NM-
042-AD.

Effective Date

    (a) This AD becomes effective October 14, 2008.

Affected ADs

    (b) This AD supersedes AD 2008-04-02.

Applicability

    (c) This AD applies to Bombardier Model DHC-8-400, DHC-8-401, 
and DHC-8-402 airplanes, certificated in any category; serial 
numbers 4001 and 4003 through 4176 inclusive.

Unsafe Condition

    (d) This AD results from reports of cracking in the barrel nuts 
at the four primary front spar wing-to-fuselage attachment joints. 
We are issuing this AD to detect and correct cracking of the barrel 
nuts at the wing front spar wing-to-fuselage joints, which could 
result in reduced structural integrity of the wing-to-fuselage 
attachments and consequent detachment of the wing.

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.

Restatement of Requirements of AD 2008-04-02 With New Service 
Information

Inspections and Corrective Actions

    (f) Within 50 flight hours after February 13, 2008 (the 
effective date of AD 2008-04-02), inspect all barrel nuts, part 
number DSC228-16, to determine if the barrel nuts are identified 
with a marking of LH7940T SPS 01. Inspect in accordance with the 
Accomplishment Instructions of Bombardier Alert Service Bulletin 
A84-57-19, Revision A, dated February 6, 2008; or Revision B, dated 
March 6, 2008. As of the effective date of this AD, Bombardier Alert 
Service Bulletin A84-57-19, Revision B, dated March 6, 2008, must be 
used.
    (1) If no barrel nuts are identified with a marking of LH7940T 
SPS 01, no further actions are required by this paragraph.
    (2) If any barrel nut is found that is identified with a marking 
of LH7940T SPS 01, before further flight, inspect the inboard and 
outboard bolts to determine if the bolts are pre-loaded correctly. 
Inspect in accordance with the Accomplishment Instructions of 
Bombardier Alert Service Bulletin A84-57-19, Revision A, dated 
February 6, 2008; or Revision B, dated March 6, 2008. As of the 
effective date of this AD, Bombardier Alert Service Bulletin A84-57-
19, Revision B, dated March 6, 2008, must be used.
    (i) If the pre-load is incorrect (i.e., the ring can be 
rotated), before further flight, replace all hardware at that 
location in accordance with the Accomplishment Instructions of the 
alert service bulletin.
    (ii) If the pre-load is correct, before further flight, do a 
visual inspection for cracking of the barrel nuts and cradles in 
accordance with the Accomplishment Instructions of the alert service 
bulletin.
    (A) If no cracking of the barrel nut and cradle is found, do the 
applicable action required by paragraph (g) of this AD.
    (B) If no cracking of the barrel nut is found and only cracking 
of the cradle is found, no action is required by this paragraph 
provided that the applicable corrective action specified in 
paragraph (g) of this AD is done.
    (C) If any cracking of the barrel nut is found, before next 
flight, replace all hardware only at that location in accordance 
with the Accomplishment Instructions of the alert service bulletin.
    (g) For any barrel nuts on which no cracking of the barrel nut 
was found during the inspection required by paragraph (f)(2)(ii) of 
this AD, do the applicable corrective action specified in paragraph 
(g)(1), (g)(2), (g)(3), (g)(4), or (g)(5) of this AD at the 
compliance time specified in the applicable paragraph.
    (1) If four barrel nuts having no cracking are found, do the 
actions specified in paragraphs (g)(1)(i), (g)(1)(ii), and 
(g)(1)(iii) of this AD.
    (i) Within 50 flight hours after doing the inspection required 
by paragraph (f)(2)(ii) of this AD, repeat the inspection specified 
in paragraph (f)(2) of this AD. Thereafter, repeat the inspection at 
intervals not to exceed 50

[[Page 51905]]

flight hours until the replacement specified in paragraph (g)(1)(ii) 
of this AD is done.
    (ii) Within 100 flight hours after doing the inspection required 
by paragraph (f)(2)(ii) of this AD, replace all hardware at the 
left-hand outboard location and the right-hand outboard location in 
accordance with the Accomplishment Instructions of Bombardier Alert 
Service Bulletin A84-57-19, Revision A, dated February 6, 2008; or 
Revision B, dated March 6, 2008. As of the effective date of this 
AD, Bombardier Alert Service Bulletin A84-57-19, Revision B, dated 
March 6, 2008, must be used. Replacing the barrel nuts on the 
outboard locations terminates the requirement to do the repetitive 
inspections specified in paragraph (g)(1)(i) of this AD.
    (iii) Within 100 flight hours after doing the replacement 
required by paragraph (g)(1)(ii) of this AD, repeat the inspection 
specified in paragraph (f)(2) of this AD for the remaining barrel 
nuts identified with a marking of LH7940T SPS 01. Thereafter, repeat 
the inspection at intervals not to exceed 100 flight hours until the 
replacement of all hardware at those locations is done. Do the 
inspection and replacement in accordance with the Accomplishment 
Instructions of Bombardier Alert Service Bulletin A84-57-19, 
Revision A, dated February 6, 2008; or Revision B, dated March 6, 
2008. As of the effective date of this AD, Bombardier Alert Service 
Bulletin A84-57-19, Revision B, dated March 6, 2008, must be used.
    (2) If three barrel nuts having no cracking are found, do the 
actions specified in paragraphs (g)(2)(i), (g)(2)(ii), and 
(g)(2)(iii) of this AD.
    (i) Within 50 flight hours after doing the inspection required 
by paragraph (f)(2)(ii) of this AD, repeat the inspection specified 
in paragraph (f)(2) of this AD. Thereafter, repeat the inspection at 
intervals not to exceed 50 flight hours until the replacement 
specified in paragraph (g)(2)(ii) of this AD is done.
    (ii) Within 100 flight hours after doing the inspection required 
by paragraph (f)(2)(ii) of this AD, replace all hardware for one 
affected barrel nut at the outboard location, on the side with two 
affected barrel nuts, in accordance with the Accomplishment 
Instructions of Bombardier Alert Service Bulletin A84-57-19, 
Revision A, dated February 6, 2008; or Revision B, dated March 6, 
2008. As of the effective date of this AD, Bombardier Alert Service 
Bulletin A84-57-19, Revision B, dated March 6, 2008, must be used. 
Replacing the barrel nut on the outboard location terminates the 
requirement to do the repetitive inspections specified in paragraph 
(g)(2)(i) of this AD.
    (iii) Within 100 flight hours after doing the replacement 
required by paragraph (g)(2)(ii) of this AD, repeat the inspection 
specified in paragraph (f)(2) of this AD for the remaining barrel 
nuts identified with a marking of LH7940T SPS 01. Thereafter, repeat 
the inspection at intervals not to exceed 100 flight hours until the 
replacement of all hardware at those locations is done. Do the 
inspection and replacement in accordance with the Accomplishment 
Instructions of Bombardier Alert Service Bulletin A84-57-19, 
Revision A, dated February 6, 2008; or Revision B, dated March 6, 
2008. As of the effective date of this AD, Bombardier Alert Service 
Bulletin A84-57-19, Revision B, dated March 6, 2008, must be used.
    (3) If two barrel nuts having no cracking are found and both 
nuts are on the same side, do the actions specified in paragraphs 
(g)(3)(i), (g)(3)(ii), and (g)(3)(iii) of this AD.
    (i) Within 100 flight hours after doing the inspection required 
by paragraph (f)(2)(ii) of this AD, repeat the inspection specified 
in paragraph (f)(2) of this AD. Thereafter, repeat the inspection at 
intervals not to exceed 100 flight hours until the replacement 
specified in paragraph (g)(3)(ii) of this AD is done.
    (ii) Within 500 flight hours after doing the inspection required 
by paragraph (f)(2)(ii) of this AD, replace all hardware for one 
affected barrel nut at the outboard location that has two affected 
barrel nuts in accordance with the Accomplishment Instructions of 
Bombardier Alert Service Bulletin A84-57-19, Revision A, dated 
February 6, 2008; or Revision B, dated March 6, 2008. As of the 
effective date of this AD, Bombardier Alert Service Bulletin A84-57-
19, Revision B, dated March 6, 2008, must be used. Replacing the 
barrel nut on the outboard location terminates the requirement to do 
the repetitive inspections specified in paragraph (g)(3)(i) of this 
AD.
    (iii) Within 100 flight hours after doing the replacement 
required by paragraph (g)(3)(ii) of this AD, repeat the inspection 
specified in paragraph (f)(2) of this AD for the remaining barrel 
nut identified with a marking of LH7940T SPS 01. Thereafter, repeat 
the inspection at intervals not to exceed 100 flight hours until the 
replacement of all hardware at that location is done. Do the 
inspection and replacement in accordance with the Accomplishment 
Instructions of Bombardier Alert Service Bulletin A84-57-19, 
Revision A, dated February 6, 2008; or Revision B, dated March 6, 
2008. As of the effective date of this AD, Bombardier Alert Service 
Bulletin A84-57-19, Revision B, dated March 6, 2008, must be used.
    (4) If two barrel nuts having no cracking are found and are on 
opposite sides, within 100 flight hours after doing the inspection 
required by paragraph (f)(2)(ii) of this AD, repeat the inspection 
specified in paragraph (f)(2) of this AD. Thereafter, repeat the 
inspection at intervals not to exceed 100 flight hours until the 
replacement of all hardware at those locations is done. Do the 
inspection and replacement in accordance with the Accomplishment 
Instructions of Bombardier Alert Service Bulletin A84-57-19, 
Revision A, dated February 6, 2008; or Revision B, dated March 6, 
2008. As of the effective date of this AD, Bombardier Alert Service 
Bulletin A84-57-19, Revision B, dated March 6, 2008, must be used.
    (5) If one barrel nut having no cracking is found, within 100 
flight hours after doing the inspection required by paragraph 
(f)(2)(ii) of this AD, repeat the inspection specified in paragraph 
(f)(2) of this AD. Thereafter, repeat the inspection at intervals 
not to exceed 100 flight hours until the replacement of all hardware 
at that location is done. Do the inspection and replacement in 
accordance with the Accomplishment Instructions of Bombardier Alert 
Service Bulletin A84-57-19, Revision A, dated February 6, 2008; or 
Revision B, dated March 6, 2008. As of the effective date of this 
AD, Bombardier Alert Service Bulletin A84-57-19, Revision B, dated 
March 6, 2008, must be used.

Actions Accomplished According to Previous Issue of Alert Service 
Bulletin

    (h) Actions accomplished before February 13, 2008, in accordance 
with Bombardier Alert Service Bulletin A84-57-19, dated February 1, 
2008, are acceptable for compliance with the corresponding actions 
specified in this AD.

Actions Accomplished According to Bombardier Alert Service Bulletin 
A84-57-18

    (i) For airplanes on which the actions specified in Bombardier 
Alert Service Bulletin A84-57-18, dated January 16, 2008, were 
accomplished before February 13, 2008, and on which no barrel nuts 
were found that were identified with a marking of LH7940T SPS 01: No 
further action is required by this AD.

Parts Installation

    (j) As of February 13, 2008, no person may install a barrel nut, 
part number DSC228-16, identified with a marking of LH7940T SPS 01, 
on any airplane.

New Requirement of This AD

Replacement of All Affected Barrel Nuts

    (k) For airplanes on which barrel nuts are inspected in 
accordance with paragraph (g)(1)(iii), (g)(2)(iii), (g)(3)(iii), 
(g)(4), or (g)(5) of this AD: Within 3,000 flight hours after the 
effective date of this AD, replace all hardware for all remaining 
barrel nuts, part number DSC228-16, identified with a marking of 
LH7940T SPS 01. Do the replacement in accordance with the 
Accomplishment Instructions of Bombardier Alert Service Bulletin 
A84-57-19, Revision B, dated March 6, 2008. Replacement of all 
hardware for all affected barrel nuts constitutes terminating action 
for the repetitive inspections of this AD.
    (l) For airplanes on which hardware for the barrel nut was 
replaced in accordance with Bombardier Alert Service Bulletin A84-
57-19, dated February 1, 2008; or Revision A, dated February 6, 
2008: Within 3,000 flight hours after the effective date of this AD, 
apply F13, Type 2 corrosion inhibiting compound to the affected 
bolts and barrel nuts in accordance with the Accomplishment 
Instructions of Bombardier Alert Service Bulletin A84-57-19, 
Revision B, dated March 6, 2008; except if it can be conclusively 
determined from a review of airplane maintenance records that F13, 
Type 2 corrosion inhibiting compound was applied to the affected 
bolts and barrel nuts, then no further action is required by this 
paragraph.

Special Flight Permit

    (m) Special flight permits, as described in Section 21.197 and 
Section 21.199 of the Federal Aviation Regulations (14 CFR 21.197 
and 21.199), may be issued to operate the airplane to a location 
where the requirements of this AD can be accomplished, but 
concurrence by the Manager, New York Aircraft Certification Office 
(ACO), FAA, is

[[Page 51906]]

required prior to issuance of the special flight permit. Before 
using any approved special flight permits, notify your appropriate 
principal inspector (PI) in the FAA Flight Standards District Office 
(FSDO), or lacking a PI, your local FSDO. Special flight permits may 
be permitted provided that the conditions specified in paragraphs 
(m)(1), (m)(2), (m)(3), (m)(4), and (m)(5) of this AD are met.
    (1) Both the right-hand side and left-hand side of the airplane 
must have at least one barrel nut that is not within the suspect 
batch (i.e., barrel nut is not identified with a marking of LH7940T 
SPS 01). The barrel nuts that are not within the suspect batch must 
be in good working condition (i.e., no cracking of the barrel nut).
    (2) No passengers and no cargo are onboard.
    (3) Airplane must operate in fair weather conditions with a low 
risk of turbulence.
    (4) Airplane must operate with reduced airspeed. For further 
information, contact Bombardier, Q Series 24 Hour Service Customer 
Response Center, at: Telephone 1-416-375-4000; fax 1-416-375-4539; 
E-mail: thd.qseries@aero.bombardier.com.
    (5) All of the conditions specified in paragraphs (m)(1), 
(m)(2), (m)(3), and (m)(4) of this AD are on a case-by-case basis. 
Contact your appropriate principal inspector (PI) in the FAA Flight 
Standards District Office (FSDO), or lacking a PI, your local FSDO, 
for assistance.

Alternative Methods of Compliance (AMOCs)

    (n)(1) The Manager, New York ACO, FAA, has the authority to 
approve AMOCs for this AD, if requested using the procedures found 
in 14 CFR 39.19. Send information to ATTN: Pong Lee, Aerospace 
Engineer, Airframe and Propulsion Branch, ANE-171, FAA, New York 
ACO, 1600 Stewart Avenue, Suite 410, Westbury, New York 11590; 
telephone (516) 228-7324; fax (516) 794-5531. 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.

Related Information

    (o) Canadian airworthiness directive CF-2008-11R1, dated May 9, 
2008, also addresses the subject of the AD.

Material Incorporated by Reference

    (p) You must use Bombardier Alert Service Bulletin A84-57-19, 
Revision A, dated February 6, 2008; or Bombardier Alert Service 
Bulletin A84-57-19, Revision B, dated March 6, 2008; as applicable; 
to perform the actions that are required by this AD, unless the AD 
specifies otherwise.
    (1) The Director of the Federal Register approved the 
incorporation by reference of Bombardier Alert Service Bulletin A84-
57-19, Revision B, dated March 6, 2008, in accordance with 5 U.S.C. 
552(a) and 1 CFR part 51.
    (2) On February 13, 2008 (73 FR 8187, February 13, 2008), the 
Director of the Federal Register approved the incorporation by 
reference of Bombardier Alert Service Bulletin A84-57-19, Revision 
A, dated February 6, 2008.
    (3) Contact Bombardier, Inc., Bombardier Regional Aircraft 
Division, 123 Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada, 
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 18, 2008.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E8-19718 Filed 9-5-08; 8:45 am]

BILLING CODE 4910-13-P
