                  TOXIC SUBSTANCES CONTROL ACT

                   INVENTORY REPRESENTATION FOR

           PRODUCTS CONTAINING TWO OR MORE SUBSTANCES:

                FORMULATED AND STATUTORY MIXTURES

I.  Introduction

     This paper explains the conventions that are applied to

listings of certain mixtures for the Chemical Substance Inventory

that is maintained by the U.S. Environmental Protection Agency

(EPA) under the Toxic Substances Control Act (TSCA).  This paper

discusses the Inventory representation of mixtures of substances

that do not react together (i.e., formulated mixtures) as well as

those combinations that are formed during certain manufacturing

activities and are designated as mixtures by the Agency (i.e.,

statutory mixtures).  Complex reaction products are covered in a

separate paper.  The Agency's goal in developing this paper is to

make it easier for the users of the Inventory to interpret

Inventory listings and to understand how new mixtures would be

identified for Inventory inclusion.

     Fundamental to the Inventory as a whole is the principle

that entries on the Inventory are identified as precisely as

possible for the commercial chemical substance, as reported by

the submitter.  Substances that are chemically indistinguishable,

or even identical, may be listed differently on the Inventory,

depending on the degree of knowledge that the submitters possess

and report about such substances, as well as how submitters

intend to represent the chemical identities to the Agency and to

customers.  Although these chemically indistinguishable

substances are named differently on the Inventory, this is not a

"nomenclature" issue, but an issue of substance representation.

Submitters should be aware that their choice for substance

representation plays an important role in the Agency's

determination of how the substance will be listed on the

Inventory.

=====================================

     NOTICE:  The policies set out in this document are not final

Agency action, but are intended solely as guidance.  They are not

intended, nor can they be relied upon, to create any rights

enforceable by any party in litigation with the United States.

EPA officials may decide to follow the guidance provided in this

document, or to act at variance with this guidance, based on an

analysis of specific circumstances.

II.  Definition of Terms

     TSCA identifies two types of materials:  (1) chemical

substances and (2) mixtures of chemical substances.  The

Inventory lists only chemical substances.  It does not list

mixtures; however, the individual components of mixtures are

listed separately.

     "Chemical substance" is defined in section 3 of TSCA (and

in section 710 of the Agency's implementing regulations) by

chemical composition, by source or origin and by identification

of certain categories of materials that are not considered

"chemical substances":

          "Chemical substance" means any organic or inorganic

     substance of a particular molecular identity, including --

                    (i) any combination of such substances occurring in

          whole or in part as a result of a chemical reaction or

          occurring in nature, ... .

          "Chemical substance" does not include:

                    (i) any mixture [710.2(q)], ...

     "Mixture" is defined in section 710.2(q) as:

          any combination of two or more chemical substances if the

     combination does not occur in nature and is not, in whole or

     in part, the result of a chemical reaction; except that

     "mixture" does include:

            (1) Any combination which occurs, in whole or in part, as

     a result of a chemical reaction if the combination could

     have been manufactured for commercial purposes without a

     chemical reaction at the time the chemical substances

     comprising the combination were combined and if, after the

     effective date of premanufacture notification requirements,

     none of the chemical substances comprising the combination

     is a new chemical substance, and

            (2) Hydrates of a chemical substance or hydrated ions

     formed by association of a chemical substance with water.

III.  Inventory Representations with Illustrative Examples

          A.  Mixtures resulting from blending substances that do not

     react.

     A blend of two or more substances that has been physically

combined without a chemical reaction is considered to be a

mixture.  Such a blend, as a whole entity, is excluded from the

Inventory and premanufacture notification (PMN) requirements for

new chemical substances.  Individual components of such a mixture

are separately reportable for the Inventory, however, and are

considered to be "new substances" if they are not currently

listed on the Inventory.

     Note, however, that salt formation, the creation of ionic

bonds, is considered to be a chemical reaction.

               1.  Combinations of materials that are physically

     blended or mixed together and do not themselves result in a

     chemical reaction are always considered to be mixtures.

     The exclusion of these mixtures from the Inventory applies

only to the mixture itself and not to the individual chemical

substances of which the mixture is comprised.  Each chemical

substance in a mixture requires a separate Inventory listing.

This approach affords considerable flexibility to processors, who

are allowed to make many different mixtures of Inventory-listed

substances without submitting PMNs.

               Example 1.  Consider two petroleum streams, each of which is

          a complex chemical substance.  The two streams are

          mixed, but no reaction occurs.  The Agency considers

          that the combination of the two petroleum streams

          themselves is a mixture; each would be listed

          separately on the Inventory.  A similar example from

          the petroleum industry is a blended gasoline to which a

          non-reactive corrosion inhibitor has been added.

               Example 2.  Solid solutions are treated as mixtures; they

          are found in certain alloys.  For example, gold and

          copper form solid solutions in which some of the copper

          atoms in the lattice are replaced by gold atoms.  In

          general, the gold atoms are distributed at random, and

          a range of gold-copper compositions is possible,

          according to this mixture representation for gold and

          copper.

               Example 3.  Consider a substance that is encapsulated in a

          second substance.  If the two substances do not react

          together, they are considered to be a mixture under

          TSCA if they do not constitute an article.

               Example 4.  A commercial product described as "coating

          material of linseed oil and titanium dioxide," formed

          by the intentional mixing of two or more substances,

          which produces no new substance(s) and results only in

          a combination of the mixed substances, is not itself a

          substance under TSCA.  The component substances of such

          mixtures (e.g., linseed oil and titanium dioxide),

          however, are individually reportable as substances.

               Example 5.  Consider a multi-nutrient "mixed fertilizer"

          that could have been prepared by physically blending

          dry products such as urea, superphosphate and potash or

          by chemical reaction when liquid ammonium phosphate was

          granulated with potash.  The Agency considers this

          "mixed fertilizer" a mixture of urea, superphosphate

          and potash regardless of the method used to make it.

               Example 6.  If commercially-available pine oil, a non-ionic

          surfactant, and sodium soap of coconut oil acids are

          mixed, without chemical reaction, a combination is

          produced that is a mixture.  Alternatively, if that

          same combination is prepared by mixing pine oil, the

          non-ionic surfactant, coconut oil acids and sodium

          hydroxide, and carrying out the saponification reaction

          to form the sodium soap of coconut oil acids, the

          combination would be identical to that manufactured by

          mixing the first set of substances without chemical

          reaction.  The three substances in the final

          combination (i.e., pine oil, the surfactant and the

          sodium salt of coconut oil) constitute a mixture and

          each one is subject to Inventory reporting, regardless

          of the method used to manufacture the mixture.

     In some cases two substances may be physically intertwined

such that they cannot be separated without breaking bonds of one

or the other.  As long as they have not reacted with each other

(i.e., there are no covalent bonds between the two types of

molecules), they are considered to be a mixture.  As an extreme

example, two or more intertwined rings (i.e., concatenated

molecules) that had different chemical compositions would be

considered a mixture under TSCA if, in fact, they had no covalent

bonds connecting them.

          B.  Combinations that are considered to be statutory

     mixtures under TSCA

                    1.  Certain alloys, inorganic glasses, ceramics, frits

          and cements, including Portland cement are considered

          to be statutory mixtures by the Agency.

     Inorganic glasses, ceramics, frits and cements, including

Portland cements, are considered to be statutory mixtures under

TSCA.  Manufacturers of these products are not required to report

them.  When the initial Inventory was being developed, both EPA

and industry recognized that the individual substances comprising

these mixtures are complex solids and would be very difficult to

identify.  Therefore, instead of requiring industry to identify

and report every such substance for the Inventory, several

special categories were created to include the various substances

formed when cement, glass, frit or ceramic are produced.  These

categories were reported during the initial Inventory reporting

period and are currently listed on the TSCA Inventory.  Each

category contains a definition that describes the various

components of that category in terms of the elements and the

various types of chemical substances that may be formed with

these elements.  These categories of substances are:

Cement, Portland, Chemicals             [65997-15-1* ]

Cement, Alumina, Chemicals              [65997-16-2* ]

Glass, Oxide, Chemicals                 [65997-17-3* ]

Frits, Chemicals                        [65997-18-4* ]

Steel Manufacture, Chemicals            [65997-19-5* ]

Ceramic Materials and Wares, Chemicals  [66402-68-4* ]

     For example, a category such as Ceramic Material and Wares,

Chemicals includes any combination of the elements listed in the

Inventory definition, as oxides, borides, carbides, etc., in

multiple oxidation states, or in more complex compounds.  The

listed elements included in the definition of each of these

categories are not intended to be inclusive.  EPA recognizes that

the list of elements may need to be updated from time to time as

the state of the technology changes.

     Example 7.  Glass, oxide, chemicals (CASRN 65997-17-3* )

               The definition of this substance is as follows:

                    Synonym:  Chemical substances manufactured in the

          production of inorganic glass

                    This category encompasses the various chemical

          substances manufactured in the production of inorganic

          glasses.  For purposes of this category, "glass" is

          defined as an amorphous, inorganic, transparent,

          translucent or opaque material traditionally formed by

          fusion of sources of silica with a flux, such as an

          alkali-metal carbonate, boron oxide, etc. and a

          stabilizer, into a mass which is cooled to a rigid

          condition without crystallization in the case of

          transparent or liquid-phase separated glass or with

          controlled crystallization in the case of glass-

          ceramics.  The category consists of the various

          chemical substances, other than by-products or

          impurities, which are formed during the production of

          various glasses and concurrently incorporated into a

          glass mixture.  All glasses contain one or more of

          these substances, but few, if any, contain all of them.

          The elements listed below are principally present as

          components of oxide systems but some may also be

          present as halides or chalcogenides, in multiple

          oxidation states, or in more complex compounds.  Trace

          amounts of other oxides or chemical compounds may be

          present.  Oxides of the first seven elements listed*

          comprise more than 95 percent, by weight, of the glass

          produced.

          Aluminum*                     Lanthanum

          Boron*                        Lead

          Calcium*                      Lithium

          Magnesium*                    Manganese

          Potassium*                    Molybdenum

          Silicon*                      Neodymium

          Sodium*                       Nickel

          Antimony                      Niobium

          Arsenic                       Nitrogen

          Barium                        Phosphorus

          Bismuth                       Praseodymium

          Cadmium                       Rudibium

          Carbon                        Selenium

          Cerium                        Silver

          Cesium                        Strontium

          Chromium                      Sulfur

          Cobalt                        Tellurium

          Copper                        Tin

          Germanium                     Titanium

          Gold                          Tungsten

          Holmium                       Uranium

          Iron                          Vanadium

                                        Zinc

     Definitions such as this may be subject to revision to

reflect changes in the underlying technology.

     Alloys that are solid or liquid mixtures of two or more

metals or of one or more metals with certain nonmetallic elements

(e.g., certain carbon steels), are considered mixtures and are

not reportable.  However, intermetallic compounds of well-defined

stoichiometry are not considered alloys and should be reported.

                    2.  Certain combinations of metals, inorganic metal

          compounds and inert supports, which are frequently used

          for commercial purposes, including for use as solid

          phase heterogeneous catalysts, are also considered to

          be mixtures for the purposes of the TSCA Inventory.

               Example 8.  Consider the following supported catalysts:

          Pt supported on SiO2, Al2O3 or C

          Pd supported on SiO2, Al2O3 or C

          Rh supported on SiO2, Al2O3 or C

          Ni supported on SiO2, Al2O3 or C

                    In supported catalysts, the catalytic ingredient is

          dispersed in the internal porosity of such supports as

          silica gel, alumina or charcoals.  Tiny crystallites of

          such metals as platinum, palladium, rhodium and nickel

          can be formed in the pore structure.  Supported

          catalysts have much larger surface area of the

          catalytic ingredient and are much more resistant to

          coalescence of the catalytic ingredient than are

          powders.  For example, the supported catalyst Pt/C was

          prepared by the reduction of PtCl2 adsorbed on

          charcoal.  Although a reaction was involved in the

          preparation, the resultant catalyst is represented in

          terms of the products formed and is viewed under TSCA

          as a mixture of the two substances, platinum and

          carbon.

               Example 9.  Zeolites are considered for TSCA purposes to be

          mixtures of the substances used to manufacture them.

          The individual reactant materials used to produce

          zeolites are required to be listed separately on the

          Inventory.  The application of EPA's guidance is not

          affected by the chemical composition of the zeolite

          under consideration.

     EPA recognizes zeolites as a family of aluminosilicates

manufactured from a number of commercial processes and techniques

that utilize different proportions of alumina, silica and a

variety of sources of different inorganic and organic cations.

The final zeolites are characterized by covalently linked AlO4

and SiO4 tetrahedra.  Zeolites as a class of substances are

considered mixtures under TSCA regardless of the commercial

manufacturing processes and reactants utilized to achieve the

desired chemical composition of the final zeolite structure.

               Example 10.  Consider a cobalt oxide-aluminum oxide

          catalyst.  A mixed hydroxide precipitate formed by the

          reaction of sodium hydroxide and an aqueous solution of

          cobalt (II) nitrate and aluminum nitrate is heated in

          air to produce a mixed oxide catalyst.  Some of the

          cobalt is known to be oxidized to Co(III) in the

          process.  In this case, cobalt (II) oxide, cobalt (III)

          oxide and aluminum oxide would each be reported for the

          Inventory.  More complex compounds of cobalt and/or

          aluminum which may be formed incidentally in the

          manufacture of the catalyst mixture are not reported.

          C.  Hydrates of a chemical substance or hydrated ions formed

     by association of a chemical substance with water are

     considered to be mixtures of the anhydrous form of the

     chemical substance and water.

     Hydrated forms of chemical substances are exempt from the

Inventory as mixtures; the anhydrous chemical substances,

however, are reportable for the Inventory.  Thus the manufacturer

of hydrated copper sulfate, CuSO4.(H2O)x, would use the anhydrous

form, CuSO4, for Inventory purposes.

               Example 11.  Na2CO3.10H2O is a mixture of Na2CO3 and H2O;

          CuSO4.5H2O is a mixture of CuSO4 and H2O.  The anhydrous

          forms, Na2CO3 and CuSO4, are subject to reporting under

          TSCA.

     This provision does not apply to the product of discrete

chemical reactions in which either water or a solvent is a

reactant.  For example, hydrates are not formed when water reacts

with an ester to form an acid and an alcohol; likewise,

substances with Chemical Abstracts (CA) names containing the term

"hydrolyzed" are not hydrates.  Similarly, metal hydroxides

formed by the reactions of metal oxides with water are not

considered to be hydrates for TSCA Inventory purposes.

               Example 12.  A stable, hydrated complex of two substances

          and water is considered to be a mixture of the three

          chemicals.  In this case, the only chemical interaction

          between the three entities is hydrogen bonding, which

          EPA does not recognize as bonding for purposes of

          chemical identification under TSCA.

     Hydrogen bonding does not result in the formation of a new

chemical substance for the purposes of TSCA, even though it has

significant effects on physical properties.  For example, the

hydrogen of the chloroform molecule, Cl3CH, forms hydrogen bonds

with an electron pair of the oxygen of the acetone molecule,

Cl3CH   O=C(CH3)2, and chloroform-acetone mixtures have higher

boiling points than either pure component.  This type of

interaction between two molecules is caused by the

electronegative atoms (such as fluorine, nitrogen or oxygen) in

one molecule and hydrogen atoms bound to electronegative atoms in

another molecule.  The hydrogen-bonded materials are considered

to be mixtures for the purposes of TSCA.

               Example 13.  Consider the reaction of calcium oxide (CaO)

          (CASRN 1305-78-8) with water (CASRN 7732-18-5) to form

          calcium hydroxide (Ca(OH)2) (CASRN 1305-62-0).  The

          calcium hydroxide is not a hydrate with water and thus

          would require its own Inventory listing.

                     CaO  +  H2O     Ca(OH)2

               Example 14.  Consider the reaction of acetyl chloride

          (CASRN 75-36-5) with water (CASRN 7732-18-5) to form

          acetic acid (CASRN 64-19-7) and hydrochloric acid

          (CASRN 7647-01-0).  Both products of this reaction

          would require Inventory listing.

             CH3-COCl  +  H2O     CH3-COOH  +  HCl

          D.  Surface Treatment

     With this term the Agency generally means the process of

chemically treating the surface of a substance, the substrate,

with another substance so as to enhance some physical property of

the surface of the substrate or to impart chemical reactivity to

the surface (i.e., to functionalize the surface chemically).  The

surface-treating substance adheres to the surface by van der

Waal's forces, ionic bonds or covalent bonds.  If the substance

only alters a physical characteristic, the combination of the

surface treatment substance and the substrate is considered to be

a mixture of two substances, each requiring its own Inventory

listing.  If, however, the surface treatment is intended to

impart chemical reactivity, the reaction product is required to

be on the Inventory.

     Example 15.  Consider the following reaction:

            º                                        º   Me

            º                                        º

            º-OH                                     º-O-SiC10H21

     silica º     +  ClSiMe2C10H21    ---->   silica º

            º-OH                                     º   Me

     silica surface                            hydrophobic silica

                    In this example, the silica surface was modified by a

          chemical reaction to introduce a material onto the

          outermost layer of the silica, contributing the

          property of hydrophobicity to the silica without

          changing the bulk properties of the silica.  This type

          of reaction is usually not stoichiometric and would not

          be reportable under TSCA.

               Example 16.  On the other hand, if the surface of the

          substrate is functionalized, the reaction product

          formed upon reaction of the substrate and surface

          treating substance is considered to be a reportable

          substance, as illustrated below:

           º                                      º

           º-OH                                   º-O-Si(CH2)3NH2

     glass º    + (EtO)3Si(CH2)3NH2 ----> glass   º

           º-OH                                   º

     glass surface       silane              coupling agent

                                             chemically bonded to

                                             surface, providing

                                             amine functionality

                    The glass filler (particles, spheres, flakes and

          fibers) is coated with an organofunctional silane.

          Chemical modification of the filler through treatment

          with the silane is necessary to promote interfacial

          adhesion between the filler and a polymer in making

          polymer blends, which allows for uniform dispersion of

          the filler in the polymer blend.  Such functionalized

          glasses, which are formed by chemical reactions, are

          reportable substances and not considered mixtures under

          TSCA.  Generally, when the surface of glass or silica

          is modified to incorporate certain functional group(s)

          intended to react with other chemical substance(s), the

          Agency considers the surface modified glass or silica

          to be a chemical substance.

               Example 17.  If a functionalized glass sphere is coated with

          a polymer having reactive sites capable of reaction

          with the functionalized glass, the functionalized

          glass-polymer reaction product is not reportable.  This

          type of substance is generally a combination of two or

          more materials present as separate phases and combined

          to form desired structures that take advantage of

          certain desirable mechanical/physical properties of

          each component.  Chemical reactions merely take place

          over the interface region of the polymeric matrix and

          the dispersed particulate (filler) phases.  The Agency

          considers such combinations comprising separate phases

          in the polymer blend to be, for purposes of TSCA, the

          same as a physical suspension of the functionalized

          filler in the polymer.  Consequently, this type of

          material is considered to be a mixture of the

          suspending filler(s) and polymer(s), even though a

          reaction was involved.

      º                                    º

      º-O-Si(CH2)3NH2                      º-O-Si(CH2)3NHCO/\/\/

glass º                       ---> glass   º

      º         + HO2C/\/\/\               º

      º-O                                  º

Functionalized    Polyester                The linking moiety at

Glass             molecule with            the interface between

                  its acid end             polyester and glass

                  group


[Federal Register Volume 76, Number 86 (Wednesday, May 4, 2011)]
[Notices]
[Pages 25320-25321]
[FR Doc No: 2011-10746]

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

DEPARTMENT OF ENERGY

Federal Energy Regulatory Commission

[Project No. 13851-000]

Indian Blanket Water LLC; Notice of Preliminary Permit
Application Accepted for Filing and Soliciting Comments, Motions To
Intervene, and Competing Applications

    On September 30, 2010, Indian Blanket Water LLC filed an
application, pursuant to section 4(f) of the Federal Power Act,
proposing to study the feasibility of hydropower near the town of
Clayton, on the Kiamichi River in Pushmataha County, Oklahoma. The sole
purpose of a preliminary permit, if issued, is to grant the permit
holder priority to file a license application during the permit term. A
preliminary permit does not authorize the permit holder to perform any
land-disturbing

activities or otherwise enter upon lands or waters owned by others
without the owners' express permission.
    The proposed pumped storage project would consist of the following:
(1) A 120-foot-high, 3,200-foot-long earth embankment dam; (2) a 30-
foot-high, 300-foot-long earth embankment saddle dam creating; (3) an
upper reservoir with a surface area of 133 acres and an 8,300 acre-foot
storage capacity; (4) a 60-foot-high, 5,600-foot-long earth embankment
dam creating; (5) a lower reservoir with a surface area of 332 acres
and an 8,100 acre-foot storage capacity; (6) one 28-foot-diameter,
7,500-foot-long penstock connecting the two reservoirs; (7) a
powerhouse/pumping station containing 3 pump/generating units with a
total generating capacity of 750 megawatts; (8) a 5-foot-high, 200-
foot-long diversion dam on the Kiamichi River for filling the
reservoirs creating; (9) a reservoir, on the Kiamichi River, with a
surface area of 50 acres and an 250 acre-foot storage capacity; (10) a
24-inch-diameter, 7,000-foot-long pipeline from the diversion dam to
the lower reservoir and (11) a transmission line to an existing
distribution line. The proposed project would have an average annual
generation of 1,920,000 megawatt-hours (MWh), which would be sold to a
local utility.
    Applicant Contact: Mr. Fred Brown, 4265 Kellway Circle, Addison,
Texas 75001; phone<PHONE_NUMBER>.
    FERC Contact: Michael Spencer,<PHONE_NUMBER>.
    Deadline for filing comments, motions to intervene, competing
applications (without notices of intent), or notices of intent to file
competing applications: 60 days from the issuance of this notice.
Competing applications and notices of intent must meet the requirements
of 18 CFR 4.36. Comments, motions to intervene, notices of intent, and
competing applications may be filed electronically via the Internet.
See 18 CFR 385.2001(a)(1)(iii) and the instructions on the Commission's
Web site http://www.ferc.gov/docs-filing/efiling.asp. Commenters can
submit brief comments up to 6,000 characters, without prior
registration, using the eComment system at http://www.ferc.gov/docs-filing/ecomment.asp. You must include your name and contact information
at the end of your comments. For assistance, please contact FERC Online
Support at<EMAIL_ADDRESS>call toll-free at (866) 208-
3676; or, for TTY, contact<PHONE_NUMBER>. Although the Commission
strongly encourages electronic filing, documents may also be paper-
filed. To paper-file, mail an original and seven copies to: Kimberly D.
Bose, Secretary, Federal Energy Regulatory Commission, 888 First
Street, NE., Washington, DC 20426.
    More information about this project, including a copy of the
application, can be viewed or printed on the ``eLibrary'' link of the
Commission's Web site at http://www.ferc.gov/docs-filing/elibrary.asp.
Enter the docket number (P-13851-000) in the docket number field to
access the document. For assistance, contact FERC Online Support.

    Dated: April 27, 2011.
Kimberly D. Bose,
Secretary.
[FR Doc. 2011-10746 Filed 5-3-11; 8:45 am]
BILLING CODE 6717-01-P


[Federal Register: October 29, 2008 (Volume 73, Number 210)]
[Rules and Regulations]
[Page 64191-64194]
[DOCID:fr29oc08-3]

=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-0555; Directorate Identifier 2008-NM-074-AD;
Amendment 39-15705; AD 2005-13-02 R1]
RIN 2120-AA64

Airworthiness Directives; Bombardier Model CL-600-2C10 (Regional
Jet Series 700 & 701) Series Airplanes and Model CL-600-2D24 (Regional
Jet Series 900) Series Airplanes

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

ACTION: Final rule.

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

SUMMARY: The FAA is revising an existing airworthiness directive (AD)
that applies to certain Bombardier Model CL-600-2C10 (Regional Jet
series 700 & 701) series airplanes and Model CL-600-2D24 (Regional Jet
series 900) series airplanes. That AD currently requires revising the
Airworthiness Limitations section of the Instructions of Continued
Airworthiness by incorporating new repetitive inspections and an
optional terminating action for the repetitive inspections, and
repairing any crack. This new AD clarifies the applicability of the
existing AD. This AD results from reports of hydraulic pressure loss in
either the number 1 or number 2 hydraulic system due to breakage or
leakage of hydraulic lines in the aft equipment bay and reports of
cracks on the aft pressure bulkhead web around the feed-through holes.
We are issuing this AD to prevent loss of hydraulic pressure, which
could result in reduced controllability of the airplane, and to detect
and correct cracks on the aft pressure bulkhead web, which could result
in reduced structural integrity of the aft pressure bulkhead.

DATES: This AD is effective December 3, 2008.
    On July 27, 2005 (70 FR 35987, June 22, 2005), the Director of the
Federal Register approved the incorporation by reference of Bombardier
CRJ 700/900 Series Temporary Revision MRM2-129, dated June 1, 2004.

ADDRESSES: For service information identified in this AD, contact
Bombardier, Inc., Canadair, Aerospace Group, P.O. Box 6087, Station
Centre-ville, Montreal, Quebec H3C 3G9, 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<PHONE_NUMBER>) 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<PHONE_NUMBER>; fax<PHONE_NUMBER>.

SUPPLEMENTARY INFORMATION:

Discussion

    The FAA proposed to amend part 39 of the Federal Aviation
Regulations (14 CFR part 39) with an airworthiness directive (AD) to
revise AD 2005-13-02, amendment 39-14138 (70 FR 35987, June 22, 2005).
The existing AD applies to certain Bombardier Model CL-600-2C10
(Regional Jet series 700 & 701) series airplanes and Model CL-600-2D24
(Regional Jet series 900) series airplanes. The proposed AD was
published in the Federal Register on May 19, 2008 (73 FR 28754) to
continue to revise the Airworthiness Limitations section of the
Instructions of Continued Airworthiness by incorporating new repetitive
inspections and an optional terminating action for the repetitive
inspections, and repairing any crack. The proposed AD also clarifies
the applicability of the existing AD.

Comments

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

Request To Withdraw NPRM

    Comair requests that the NPRM be withdrawn. Comair states that the
minor editorial correction to the Applicability section of the NPRM
should not warrant a revised or new directive, and that the revised AD
will not increase the airworthiness of any airplane. Comair also states
that a review of the airplane log will indicate which service bulletins
have been incorporated by Bombardier, on a limited basis, before
delivery to a customer.
    We do not agree with Comair to withdraw the NPRM. When a previously
issued AD is changed, we issue a correction, revision, or supersedure
AD, depending on the nature of the material being changed. In the case
of this AD, a revision AD is the appropriate means to clarify the
Applicability section of AD 2005-13-02. We have determined that
issuance of this AD is necessary because Bombardier does not
incorporate service bulletins in production and operators may
misinterpret which affected airplanes are subject to the requirements
of this AD.

Requests To Revise the Applicability Section

    Comair notes that Bombardier Service Bulletin 670BA-29-008 is
currently at Revision B, dated August 28, 2007. Paragraph (c) of the
NPRM (i.e., Applicability section) refers to the initial issue, dated
March 12, 2004; and Revision A, dated May 5, 2004; of that service
bulletin.
    From this comment, we infer that Comair is requesting that
paragraph (c) of the NPRM be revised to also exclude those airplanes on
which Revision B of Bombardier Service Bulletin 670BA-29-008 has been
incorporated. We agree and revised paragraph (c) of this AD
accordingly.
    Comair requests that the serial numbers for Model CL-600-2C10
series airplanes identified in Table 1 of the NPRM be limited to serial
numbers 10003 through 10156 inclusive. Comair states that comments were
submitted to the NPRM for AD 2005-13-02 to limit the serial number
range for which that AD should apply. In the preamble of the final rule
for AD 2005-13-02, Comair notes that the FAA agreed with that comment
but believes that we made a mistake by not revising the serial numbers
in Table 1 of that AD (which is retained in the NPRM). Although not
addressed in its NPRM comment for AD 2005-13-02, Comair also requests
that, for the reason discussed previously, Table 1 of the NPRM be
limited to serial numbers 15001 through 15026 inclusive for Model CL-
600-2D24 series airplanes. Comair states that it does not make sense to
issue an AD against airplane serial numbers for which there is no
action required.
    We do not agree with Comair's request to revise Table 1 of this AD.
As stated in the preamble of AD 2005-13-02, we revised the
applicability of that AD to exclude those airplanes on which certain
modification summaries and service information had been incorporated.
This approach rather than changing the reference to certain serial
numbers, accomplishes the same intent. The referenced modification
summaries and service information in this AD (i.e., Modification
Summaries 670T00494 or 670T11944; Modification Summary 670T11508; and
Bombardier Service Bulletin 670BA-29-008, dated March 12, 2004,
Revision A, dated May 5, 2004, or Revision B, dated August 28, 2007)
identify the serial numbers of those airplanes. Therefore, we find no
change to this AD is necessary in this regard.

Request To Revise Costs of Compliance Section

    Comair requests that the number of U.S.-registered airplanes
specified in the Costs of Compliance section of the NPRM be changed
from 116 to 255. Comair states that the Costs of Compliance section
takes into account that either only airplanes with serial numbers below
10157 and 15027 are affected by this AD or the number needs to be
adjusted to today's U.S. registry level. Comair states that a
conversation with a Bombardier Field Service Representative indicates
that all affected serial numbers have had the modification summaries
and/or service bulletin specified in paragraph (c) of the NPRM
incorporated and thus the NPRM does not apply to any U.S registered
airplanes.
    We agree with Comair to revise the Costs of Compliance section of
this AD to reflect the current number of affected airplanes on the U.S.
registry (i.e., 324 airplanes). We consulted with Bombardier and
confirmed that all affected Bombardier Model CL-600-2C10 (Regional Jet
series 700 & 701) series airplanes and Model CL-600-2D24 (Regional Jet
series 900) series airplanes have been modified according to the
optional terminating action specified in this AD. Therefore, currently,
this AD imposes no additional financial burden on any U.S. operator. We
have also revised the Costs of Compliance section of this AD in this
regard.

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

    This AD affects about 324 airplanes of U.S. registry. We have been
advised that all affected Bombardier Model CL-600-2C10 (Regional Jet
series 700 & 701) series airplanes and Model CL-600-2D24 (Regional Jet
series 900) series airplanes on the U.S. Register have been modified
according to the optional terminating action specified in this AD.
Therefore, currently, this AD imposes no additional financial burden on
any U.S. operator.
    However, if an unmodified airplane is imported and placed on the
U.S. Register in the future, the actions required by this AD would take
about 1 work hour per airplane, at an average labor rate of $80 per
work hour. Based on these figures, we estimate the cost of this AD to
be $80 per airplane.

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 39-14138 (70 FR 35987, June 22, 2005) and adding the
following new airworthiness directive (AD):

2005-13-02 Bombardier, Inc. (Formerly Canadair): Amendment 39-15705.
Docket No. FAA-2008-0555; Directorate Identifier 2008-NM-074-AD.

Effective Date

    (a) This airworthiness directive (AD) is effective December 3,
2008.

Affected ADs

    (b) This AD revises AD 2005-13-02.

Applicability

    (c) This AD applies to the airplanes listed in Table 1 of this
AD, certificated in any category, excluding those airplanes on which
Modification Summary 670T00494 or 670T11944; and Modification
Summary 670T11508 or Bombardier Service Bulletin 670BA-29-008, dated
March 12, 2004, Revision A, dated May 5, 2004, or Revision B, dated
August 28, 2007; has been incorporated.

                         Table 1--Applicability
------------------------------------------------------------------------
       Bombardier model                        Serial No.
------------------------------------------------------------------------
 (1) CL-600-2C10 (Regional Jet   10003 through 10999 inclusive.
 Series 700 & 701) series
 airplanes.
 (2) CL-600-2D24 (Regional Jet   15001 through 15990 inclusive.
 Series 900) series airplanes.
------------------------------------------------------------------------

Unsafe Condition

    (d) This AD resulted from reports of hydraulic pressure loss in
either the number 1 or number 2 hydraulic system due to breakage or
leakage of hydraulic lines in the aft equipment bay and reports of
cracks on the aft pressure bulkhead web around the feed-through
holes. We are issuing this AD to prevent loss of hydraulic pressure,
which could result in reduced controllability of the airplane, and
to detect and correct cracks on the aft pressure bulkhead web, which
could result in reduced structural integrity of the aft pressure
bulkhead.

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 2005-13-02

Revision of Airworthiness Limitations Section

    (f) Within 30 days after July 27, 2005 (the effective date of AD
2005-13-02), revise the Airworthiness Limitations section of the
Instructions of Continued Airworthiness by inserting a copy of the
new repetitive inspections and an optional terminating action of
Bombardier CRJ 700/900 Series Temporary Revision (TR) MRM2-129,
dated June 1, 2004, into section 1.4, Part 2 (Airworthiness
Limitations), of Bombardier Regional Jet Model CL-600-2C10 and CL-
600-2D24 Maintenance Requirements Manual, CSP B-053. Thereafter,
except as provided in paragraph (h)(2) or (i) of this AD, no
alternative structural inspection intervals may be approved for this
aft pressure bulkhead and pylon pressure pan in the vicinity of the
hydraulic fittings and the hydraulic tube adapters.
    (g) When the information in TR MRM2-129, dated June 1, 2004, is
included in the general revisions of the Maintenance Requirement
Manual, the general revisions may be inserted into the Airworthiness
Limitations section of the Instructions of Continued Airworthiness
and this TR may be removed.

Corrective Action

    (h) If any crack is found during any inspection done in
accordance with Bombardier CRJ 700/900 Series TR MRM2-129, dated
June 1, 2004, or the same inspection specified in the general
revisions of the Maintenance Requirement Manual, do the actions
specified in paragraphs (h)(1) and (h)(2) of this AD.
    (1) Before further flight, repair the crack in accordance with a
method approved by either the Manager, New York Aircraft
Certification Office (ACO), FAA; or Transport Canada Civil Aviation
(TCCA) (or its delegated agent).
    (2) At the applicable time specified in paragraph (h)(2)(i) or
(h)(2)(ii) of this AD, revise the Airworthiness Limitations section
of the Instructions of Continued Airworthiness by inserting a copy
of the inspection requirements for the repair required by paragraph
(h)(1) of this AD into Section 1.4, Part 2 (Airworthiness
Limitations), of Bombardier Regional Jet Model CL-600-2C10 and CL-
600-2D24 Maintenance Requirements Manual, CSP B-053. Thereafter,
except as provided in paragraph (i) of this AD, no alternative
structural inspection intervals may be approved for this aft
pressure bulkhead and pylon pressure pan in the vicinity of the
hydraulic fittings, and the hydraulic tube adapters.
    (i) If the repair required by paragraph (h)(1) of this AD is
done after the effective date of this AD: Revise the Airworthiness
Limitations section within 12 months after the repair.
    (ii) If the repair required by paragraph (h)(1) of this AD was
accomplished before July 27, 2005: Revise the Airworthiness

Limitations section within 12 months after the repair or 30 days
after July 27, 2005, whichever occurs later.

Alternative Methods of Compliance (AMOCs)

    (i)(1) The Manager, New York ACO, FAA, 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<PHONE_NUMBER>; fax<PHONE_NUMBER>; has the authority to
approve AMOCs for this AD, if requested using 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.

Related Information

    (j) Canadian airworthiness directive CF-2004-14, dated July 20,
2004, also addresses the subject of this AD.

Material Incorporated by Reference

    (k) You must use Bombardier CRJ 700/900 Series Temporary
Revision MRM2-129, dated June 1, 2004, to perform the actions that
are required by this AD, unless the AD specifies otherwise.
    (1) On July 27, 2005 (70 FR 35987, June 22, 2005), the Director
of the Federal Register approved the incorporation by reference of
Bombardier CRJ 700/900 Series Temporary Revision MRM2-129, dated
June 1, 2004.
    (2) Contact Bombardier, Inc., Canadair, Aerospace Group, P.O.
Box 6087, Station Centre-ville, Montreal, Quebec H3C 3G9, 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<PHONE_NUMBER>, or go to: http://www.archives.gov/federal-
register/cfr/ibr-locations.html.

    Issued in Renton, Washington, on October 9, 2008.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E8-25637 Filed 10-28-08; 8:45 am]

BILLING CODE 4910-13-P