Document ID: FAA-2021-0197-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: Airbus Helicopters
Posted Date: 2021-07-22T04:00Z

[Federal Register Volume 86, Number 138 (Thursday, July 22, 2021)]
[Proposed Rules]
[Pages 38608-38612]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-15477]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0197; Project Identifier 2018-SW-107-AD]
RIN 2120-AA64

Airworthiness Directives; Airbus Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for Airbus Helicopters Model EC 155B and EC155B1 helicopters. This 
proposed AD would require replacing the main gearbox (MGB), or as an 
alternative, replacing the epicyclic reduction gear module for certain 
serial numbered planet gear assemblies installed on the MGB. This 
proposed AD would also require inspecting the MGB magnetic plugs, MGB 
filter, and oil sump for particles. Depending on the outcome of these 
inspections, this proposed AD would require further inspections and 
replacing certain parts. This proposed AD would also prohibit 
installing certain parts. This proposed AD was prompted by the failure 
of an MGB second stage planet gear. The actions of this proposed AD are 
intended to correct an unsafe condition on these helicopters.

[[Page 38609]]

DATES: The FAA must receive comments on this proposed AD by September 
7, 2021.

ADDRESSES: You may send comments by any of the following methods:
     Federal eRulemaking Docket: Go to https://www.regulations.gov. Follow the online instructions for sending your 
comments electronically.
     Fax: (202) 493-2251.
     Mail: Send comments to the U.S. Department of 
Transportation, Docket Operations, M-30, West Building Ground Floor, 
Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590-0001.
     Hand Delivery: Deliver to the ``Mail'' address between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this proposed rule, contact 
Airbus Helicopters, 2701 North Forum Drive, Grand Prairie, TX 75052; 
telephone (972) 641-0000 or (800) 232-0323; fax (972) 641-3775; or at 
https://www.airbus.com/helicopters/services/technical-support.html. You 
may view the referenced service information at the FAA, Office of the 
Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-321, 
Fort Worth, TX 76177.

Examining the AD Docket

    You may examine the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-
0197; or in person at Docket Operations between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays. The AD docket contains 
this NPRM, the European Aviation Safety Agency (now European Union 
Aviation Safety Agency) (EASA) AD, any comments received, and other 
information. The street address for Docket Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Rao Edupuganti, Aerospace Engineer, 
Dynamic Systems Section, Technical Innovation Policy Branch, Policy & 
Innovation Division, FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177; 
telephone (817) 222-5110; email rao.edupuganti@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under ADDRESSES. Include ``Docket No. FAA-2021-0197; Project Identifier 
2018-SW-107-AD'' at the beginning of your comments. The most helpful 
comments reference a specific portion of the proposal, explain the 
reason for any recommended change, and include supporting data. The FAA 
will consider all comments received by the closing date and may amend 
this proposal because of those comments.
    Except for Confidential Business Information (CBI) as described in 
the following paragraph, and other information as described in 14 CFR 
11.35, the FAA will post all comments received, without change, to 
https://www.regulations.gov, including any personal information you 
provide. The agency will also post a report summarizing each 
substantive verbal contact received about this NPRM.

Confidential Business Information

    CBI is commercial or financial information that is both customarily 
and actually treated as private by its owner. Under the Freedom of 
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public 
disclosure. If your comments responsive to this NPRM contain commercial 
or financial information that is customarily treated as private, that 
you actually treat as private, and that is relevant or responsive to 
this NPRM, it is important that you clearly designate the submitted 
comments as CBI. Please mark each page of your submission containing 
CBI as ``PROPIN.'' The FAA will treat such marked submissions as 
confidential under the FOIA, and they will not be placed in the public 
docket of this NPRM. Submissions containing CBI should be sent to Rao 
Edupuganti, Aerospace Engineer, Dynamic Systems Section, Technical 
Innovation Policy Branch, Policy & Innovation Division, FAA, 10101 
Hillwood Pkwy., Fort Worth, TX 76177; telephone (817) 222-5110; email 
rao.edupuganti@faa.gov. Any commentary that the FAA receives which is 
not specifically designated as CBI will be placed in the public docket 
for this rulemaking.

Background

    EASA, which is the Technical Agent for the Member States of the 
European Union, has issued EASA AD 2018-0263, dated December 7, 2018 
(EASA AD 2018-0263), to correct an unsafe condition for Airbus 
Helicopters Model EC 155 B and EC 155 B1 helicopters. EASA advises that 
after an accident on a Model EC225 helicopter, an investigation 
revealed the failure of an MGB second stage planet gear. EASA states 
that one of the two types of planet gear used in the MGB epicyclic 
module is subject to higher outer race contact pressures and therefore 
is more susceptible to spalling and cracking. EASA AD 2018-0263 
consequently requires repetitive inspections of the MGB magnetic plugs, 
the MGB filer, and the oil sump for particles, and depending on the 
results of those inspections, removing or replacing certain parts. EASA 
AD 2018-0263 also requires reducing the life limit of Type Z planet 
gear assemblies. EASA AD 2018-0263 also requires, if certain gear 
assemblies are installed, either replacing the MGB or replacing the 
epicyclic reduction gear. Finally EASA AD 2018-0263 prohibits 
installing a Type Y planet gear assembly or an MGB with a Type Y planet 
gear assembly on any helicopter.

FAA's Determination

    These helicopters have been approved by EASA and are approved for 
operation in the United States. Pursuant to the FAA's bilateral 
agreement with the European Union, EASA has notified the FAA of the 
unsafe condition described in its AD. The FAA is proposing this AD 
after evaluating all known relevant information and determining that an 
unsafe condition is likely to exist or develop on other products of the 
same type designs.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Airbus Helicopters Alert Service Bulletin ASB No. 
EC155-05A034, Revision 5, dated December 4, 2018 (ASB EC155-05A34 Rev 
5) for Model EC 155 helicopters, which specifies periodic inspections 
of the MGB magnetic plugs, the MGB filter, and the oil sump for 
particles. ASB EC155-05A34 Rev 5 also specifies identifying the type of 
gear assembly installed in the MGB and replacing any Type Y planet gear 
assembly within 50 hours time-in-service (TIS). For Type Z gear 
assemblies that have logged less than 1,800 hours TIS since new, this 
service information specifies replacing the gear assembly before 
exceeding 1,800 total hours TIS, and for Type Z gear assemblies that 
have logged 1,800 or more total hours TIS, replacing the gear assembly 
within 600 hours TIS.
    The FAA also reviewed Airbus Helicopters Service Bulletin SB No. 
EC155-63-016, Revision 4, dated July 26, 2018, for Model EC 155 
helicopters. This service information specifies procedures for 
replacing the MGB epicyclic reduction gear without removing the MGB.
    This service information is reasonably available because the 
interested parties have access to it through their normal course of 
business or by the means identified in the ADDRESSES section.

[[Page 38610]]

Proposed AD Requirements in This NPRM

    This proposed AD would require for helicopters with at least one 
Type Y planet gear assembly with a certain serial number (S/N) 
installed, or at least one Type Z planet gear assembly with a certain 
S/N installed, within 10 hours TIS after the effective date of this AD 
and thereafter at intervals not to exceed 10 hours TIS, inspecting the 
MGB magnetic plugs for particles. If there are particles, the proposed 
AD would require further inspections and analyses, and replacing the 
MGB, depending on the type and the size of the particles.
    This proposed AD would also require for helicopters with a Type Y 
planet gear assembly with a certain S/N installed, within 25 hours TIS 
after the effective date of this AD, inspecting the MGB filter for 
particles. If there are particles, this proposed AD would require 
further inspections and analyses, and replacing the MGB, depending on 
the type and the size of the particles. This proposed AD would require 
for helicopters with at least one Type Y planet gear assembly with a 
certain S/N installed, within 50 hours TIS after the effective date of 
this AD, replacing the MGB. As an alternative to replacing the MGB, 
this proposed AD would allow replacing the epicyclic reduction gear in 
the affected MGB.
    Additionally, this proposed AD would require, for helicopters 
without any Type Y planet gear assembly but at least one Type Z planet 
gear assembly with a certain S/N installed, replacing the MGB within 50 
hours TIS after the effective date of this AD or before any planet gear 
assembly accumulates 1,800 total hours TIS, whichever occurs later. As 
an alternative to replacing the MGB, this proposed AD would allow 
replacing the epicyclic reduction gear in the affected MGB.
    This proposed AD would require, for helicopters with at least one 
Type Z planet gear with a certain S/N installed, within certain 
compliance times specified in the figures in this AD, inspecting the 
MGB filter and inspecting the oil sump for particles. If there are 
particles this proposed AD would require further inspections and 
analyses, and replacing the MGB, depending on the type and the size of 
the particles.
    This proposed AD would prohibit installing an MGB with a certain 
serial numbered Type Y planet gear assembly and this proposed AD would 
also prohibit installing a Type Y planet gear assembly with a certain 
S/N on any helicopter.
    This proposed AD would also prohibit installing certain serial 
numbered Type Z planet gear assemblies that have accumulated 1,800 or 
more total hours TIS and prohibit installing an MGB with certain serial 
numbered Type Z planet gear assemblies that have accumulated 1,800 or 
more total hours TIS.
    Finally, this proposed AD would prohibit installing an MGB if the 
type of the planet gear assembly cannot be determined and would also 
prohibit installing any planet gear assembly if the type cannot be 
determined.

Differences Between This Proposed AD and the EASA AD

    EASA AD 2018-0263 specifies compliance times based on flight hours 
and calendar dates. This proposed AD would set compliance times based 
on hours TIS or before further flight. EASA AD 2018-0263 allows a pilot 
to inspect the MGB magnetic plugs for particles, while this proposed AD 
would not. For helicopters with at least one affected Type Z planet 
gear assembly that has accumulated 1,800 or more total hours TIS 
installed, EASA AD 2018-0263 requires replacing the MGB or epicyclic 
reduction gear within 600 flight hours after March 16, 2018, whereas 
this proposed AD would require either of those replacements within 50 
hours TIS after the effective date of this proposed AD instead. If 
16NCD13 particles are present, EASA AD 2018-0263 requires taking a 1 
liter sample of oil and returning it to Airbus Helicopters and removing 
the MGB for depot-level inspection, whereas this proposed AD would 
require replacing the MGB instead.

Interim Action

    The FAA considers this proposed AD to be an interim action. If 
final action is later identified, the FAA might consider further 
rulemaking then.

Costs of Compliance

    The FAA estimates that this proposed AD would affect 14 helicopters 
of U.S. Registry. The FAA estimates that operators may incur the 
following costs in order to comply with this proposed AD. Labor costs 
are estimated at $85 per work-hour.
    Inspecting the magnetic plugs for particle deposits would take 
about 1 work-hour for an estimated cost of $85 per helicopter per 
inspection cycle.
    Inspecting the MGB filter and oil sump for particle deposits would 
take about 1 work-hour for an estimated cost of $85 per helicopter per 
inspection cycle.
    Replacing an MGB would take about 42 work-hours, and parts would 
cost about $295,000 (overhauled) for an estimated total cost of 
$298,570 per helicopter.
    Replacing the epicyclic reduction gear would take about 56 work-
hours and parts would cost about $11,404 for an estimated total cost of 
$16,164 per helicopter.

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.
    The FAA is 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

    The FAA 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, I certify this proposed regulation:
    1. Is not a ``significant regulatory action'' under Executive Order 
12866,
    2. Would not affect intrastate aviation in Alaska, and
    3. Would not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, 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:

[[Page 38611]]

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 FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

Airbus Helicopters: Docket No. FAA-2021-0197; Project Identifier 
2018-SW-107-AD.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by September 7, 2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Airbus Helicopters Model EC 155B and EC155B1 
helicopters, certificated in any category.

(d) Subject

    Joint Aircraft Service Component (JASC) Code: 6300, Main Rotor 
Drive System.

(e) Unsafe Condition

    This AD defines the unsafe condition as failure of a main 
gearbox (MGB) planet gear assembly. This condition could result in 
failure of the MGB and subsequent loss of helicopter control.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Required Actions

    (1) For helicopters with at least one Type Y planet gear 
assembly with a serial number (S/N) listed in Appendix 4.A. of 
Airbus Helicopters Alert Service Bulletin ASB No. EC155-05A034, 
Revision 5, dated December 4, 2018 (ASB EC-155-05A034 Rev 5) or with 
at least one Type Z planet gear assembly with an S/N listed in 
Appendix 4.B. of ASB EC155-05A034 Rev 5 installed, within 10 hours 
time-in-service (TIS) after the effective date of this AD, and 
thereafter at intervals not to exceed 10 hours TIS, inspect the MGB 
magnetic plugs for particles. If there are any particles that 
consist of any scale, flake, splinter, or other particle other than 
cotter pin fragments, pieces of lock wire, swarf, abrasion, or 
miscellaneous non-metallic waste, and any of the planet gears have 
accumulated less than 50 total hours TIS, before further flight, 
inspect the MGB filter and oil sump for particles. Thereafter, for 
25 hours TIS, continue to inspect the MGB plugs for particles before 
each flight, inspect the MGB filter and oil sump for particles at 
intervals not to exceed 25 hours TIS, and inspect the cumulative 
surface area of the particles collected from the magnetic plugs, the 
MGB filter, and the oil sump, since last MGB overhaul, or since new 
if no overhaul has been performed.
    Note to paragraph (g)(1): Airbus Helicopters service information 
refers to an MGB filter as an oil filter.
    (i) If the total surface area of the particles is less than 3 
mm\2\, examine the particles with the largest surface area (S), 
greatest length (L), and greatest thickness (e).
    (A) If any (S) of all of the particles is less than or equal to 
1 mm\2\, the (L) is less than or equal to 1.5 mm, and the (e) is 
less than or equal to 0.2 mm, inspect the MGB plugs for particles 
before further flight, and inspect the MGB filter and oil sump for 
particles within 25 hours TIS. Thereafter:
    (1) For 25 hours TIS, continue to inspect the MGB plugs for 
particles before each flight and perform the actions required by 
paragraphs (g)(1)(i) and (ii) of this AD.
    (2) Inspect the MGB filter and oil sump for particles at 
intervals not to exceed 25 hours TIS and perform the actions 
required by paragraphs (g)(1)(i) and (ii) of this AD.
    (B) If any (S) is greater than 1 mm\2\, (L) is greater than 1.5 
mm, or (e) is greater than 0.2 mm, perform a metallurgical analysis 
for any 16NCD13 particles, using a method in accordance with FAA-
approved procedures.
    (C) If there are any 16NCD13 particles, before further flight, 
replace the MGB with an airworthy MGB.
    (D) If there are no 16NCD13 particles, inspect the MGB plugs for 
particles before further flight and inspect the MGB filter and oil 
sump for particles within 25 hours TIS. Thereafter:
    (1) For 25 hours TIS, continue to inspect the MGB plugs for 
particles before each flight and perform the actions required by 
paragraphs (g)(1)(i) and (ii) of this AD.
    (2) Inspect the MGB filter and oil sump for particles at 
intervals not to exceed 25 hours TIS and perform the actions 
required by paragraphs (g)(1)(i) and (ii) of this AD.
    (ii) If the total surface area of collected particles is greater 
than or equal to 3 mm\2\, before further flight, perform a 
metallurgical analysis for any 16NCD13 particles using a method in 
accordance with FAA-approved procedures.
    (A) If there are any 16NCD13 particles, before further flight, 
replace the MGB with an airworthy MGB.
    (B) If there are no 16NCD13 particles, inspect the MGB plugs for 
particles before further flight and inspect the MGB filter and oil 
sump for particles within 25 hours TIS. Thereafter:
    (1) For 25 hours TIS, continue to inspect the MGB plugs for 
particles before each flight and perform the actions required by 
paragraphs (g)(1)(i) and (ii) of this AD.
    (2) Inspect the MGB filter and oil sump for particles at 
intervals not to exceed 25 hours TIS and perform the actions 
required by paragraphs (g)(1)(i) and (ii) of this AD.
    (2) For helicopters with at least one Type Y planet gear 
assembly with an S/N listed in Appendix 4.A. of ASB EC-155-05A034 
Rev 5 installed, within 25 hours TIS after the effective date of 
this AD, inspect the MGB filter for particles. If there are any 
particles that consist of any scale, flake, splinter, or particle 
other than cotter pin fragments, pieces of lock wire, swarf, 
abrasion, or miscellaneous non-metallic waste, and any of the planet 
gears have accumulated more than 50 total hours TIS, before further 
flight, perform the actions required by paragraphs (g)(1)(i) and 
(ii) of this AD.
    (3) For helicopters with at least one Type Y planet gear 
assembly with an S/N listed in Appendix 4.A. of ASB EC-155-05A034 
Rev 5 installed, within 50 hours TIS after the effective date of 
this AD, replace the MGB or as an alternative to replacing an 
affected MGB, replace the epicyclic reduction gear module in the 
affected MGB in accordance with paragraph 3.B.2. of the 
Accomplishment Instructions of Airbus Helicopters Service Bulletin 
SB No. EC155-63-016, Revision 4, dated July 26, 2018 (SB EC155-63-
016 Rev 4), except you are not required to contact Airbus 
Helicopters.
    (4) For helicopters without any Type Y planet gear assembly 
installed but with at least one Type Z planet gear assembly with an 
S/N listed in Appendix 4.B. of ASB EC155-05A034 Rev 5 installed, 
within 50 hours TIS after the effective date of this AD, or before 
any gear accumulates 1,800 total hours TIS, whichever occurs later, 
replace the MGB or as an alternative to replacing an affected MGB, 
replace the epicyclic reduction gear module in the affected MGB in 
accordance with paragraph 3.B.2. of the Accomplishment Instructions 
of SB EC155-63-016 Rev 4, except you are not required to contact 
Airbus Helicopters.
    (5) For helicopters with at least one Type Z planet gear 
assembly with an S/N listed in Appendix 4.B. of ASB EC155-05A034 Rev 
5 installed, inspect the MGB filter for particles within the 
compliance times specified in Figure 1 to paragraph (g)(5) of this 
AD and inspect the oil sump for particles within the compliance 
times specified in Figure 2 to paragraph (g)(5) of this AD, based on 
the total hours TIS accumulated by the Type Z planet gear with the 
most total hours TIS accumulated since first installation in an MGB. 
If there are particles, before further flight, perform the actions 
required by paragraphs (g)(1)(i) and (ii) of this AD.

[[Page 38612]]

[GRAPHIC] [TIFF OMITTED] TP22JY21.001

[GRAPHIC] [TIFF OMITTED] TP22JY21.002

    (6) As of the effective date of this AD, do not install a type Y 
planet gear assembly with an S/N listed in Appendix 4.A. of ASB 
EC155-05A034 Rev 5 on any helicopter, and do not install an MGB with 
a Type Y planet gear assembly with an S/N listed in Appendix 4.A. of 
ASB EC155-05A034 Rev 5 on any helicopter.
    (7) As of the effective date of this AD, do not install a Type Z 
planet gear assembly with an S/N listed in Appendix 4.B. of ASB 
EC155-05A034 Rev 5 that has accumulated 1,800 or more total hours 
TIS on any helicopter, and do not install an MGB with at least one 
Type Z planet gear assembly with an S/N listed in Appendix 4.B. of 
ASB EC155-05A034 Rev 5 that has accumulated 1,800 or more total 
hours TIS on any helicopter.
    (8) As of the effective date of this AD, do not install any 
planet gear on any helicopter if the planet gear assembly type 
cannot be determined, and do not install any MGB on any helicopter 
if any of the planet gear assembly types cannot be determined.

(h) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, International Validation Branch, FAA, has the 
authority to approve AMOCs for this AD, if requested using the 
procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, 
send your request to your principal inspector or local Flight 
Standards District Office, as appropriate. If sending information 
directly to the manager of the International Validation Branch, send 
it to the attention of the person identified in paragraph (i)(1) of 
this AD. Information may be emailed to: 9-AVS-AIR-730-AMOC@faa.gov.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(i) Related Information

    (1) For more information about this AD, contact Rao Edupuganti, 
Aerospace Engineer, Dynamic Systems Section, Technical Innovation 
Policy Branch, Policy & Innovation Division, FAA, 10101 Hillwood 
Pkwy., Fort Worth, TX 76177; telephone (817) 222-5110; email 
rao.edupuganti@faa.gov.
    (2) For service information identified in this AD, contact 
Airbus Helicopters, 2701 North Forum Drive, Grand Prairie, TX 75052; 
telephone (972) 641-0000 or (800) 232-0323; fax (972) 641-3775; or 
at https://www.airbus.com/helicopters/services/technical-support.html. You may view the referenced service information at the 
FAA, Office of the Regional Counsel, Southwest Region, 10101 
Hillwood Pkwy., Room 6N-321, Fort Worth, TX 76177.
    (3) The subject of this AD is addressed in European Aviation 
Safety Agency (now European Union Aviation Safety Agency) (EASA) AD 
2018-0263, dated December 7, 2018. You may view the EASA AD on the 
internet at https://www.regulations.gov in the AD Docket.

    Issued on July 14, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-15477 Filed 7-21-21; 8:45 am]
BILLING CODE 4910-13-P