[Federal Register Volume 60, Number 191 (Tuesday, October 3, 1995)]
[Rules and Regulations]
[Pages 51709-51712]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-23811]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 94-NM-211-AD; Amendment 39-9381; AD 95-20-03]
Airworthiness Directives; Learjet Model 24, 25, 28, 29, 31, 35,
36, and 55 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment supersedes an existing airworthiness directive
(AD), applicable to certain Learjet Model 24, 25, 31, 35, and 36 series
airplanes, and all Learjet Model 28, 29, and 55 series airplanes, that
currently requires a revision to the Limitations Section of the FAA-
approved Airplane Flight Manual (AFM) to prohibit flight above an
altitude of 41,000 feet. The actions specified by that AD are intended
to limit the airplane operating altitude due to a possible failure of
the outflow/safety valves, which could result in rapid decompression of
the airplane. This amendment adds a requirement for replacement of
certain outflow/safety valves, which, when accomplished, constitutes
terminating action for the previously required AFM limitation.
DATES: Effective November 2, 1995.
The incorporation by reference of certain publications, as listed
in the regulations, is approved by the Director of the Federal Register
as of November 2, 1995.
The incorporation by reference of Allied Signal Aerospace Alert
Service Bulletin 102850-21-A4021, Revision 2, dated October 6, 1994, as
listed in the regulations, was approved previously by the Director of
the Federal Register as of January 3, 1995 (59 FR 64844, December 16,
1994).
ADDRESSES: The service information referenced in this AD may be
obtained from Allied Signal, Inc., Controls & Accessories, 11100 N.
Oracle Road, Tucson, Arizona 85737-9588; telephone (602) 469-1000; and
Learjet, Inc., P.O. Box 7707, Wichita, Kansas 67277-7707. This
information may be examined at the Federal Aviation Administration
(FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue,
SW., Renton, Washington; or at the FAA, Los Angeles Aircraft
Certification Office, Transport Airplane Directorate, 3960 Paramount
Boulevard, Lakewood, California; or at the Office of the Federal
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Walter Eierman, Aerospace Engineer,
Systems and Equipment Branch, ANM-130L, FAA, Transport Airplane
Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount
Boulevard, Lakewood, California; 90712; telephone (310) 627-5336; fax
(310) 627-5210.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) by superseding AD 94-26-01,
amendment 39-9097 (59 FR 64844, December 16, 1994), which is applicable
to certain Learjet Model 24, 25, 31, 35, and 36 series airplanes, and
all Learjet Model 28, 29, and 55 series airplanes, was published in the
Federal Register on March 16, 1995 (60 FR 14231). The action proposed
to continue to require a revision to the Limitations Section of the
FAA-approved Airplane Flight Manual (AFM) to prohibit flight above an
altitude of 41,000 feet. The action also proposed to require
replacement of certain outflow/safety valves, which, when accomplished,
constitutes terminating action for the previously required AFM
limitation.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
The only commenter, Learjet, Inc., requests that the AD be written
as one AD against the outflow/safety valves, rather than against
Learjet airplanes. The commenter believes this would better serve the
public and that confusion would result if several AD's are issued
against the various aircraft that use the affected valve. Learjet
states that it is not customary to issue AD's against the aircraft for
engine problems, seat belt buckles, or any other appliance that is used
on more than one aircraft.
The FAA does not concur with the commenter's request. The FAA
responds by noting that its general policy is that, when an unsafe
condition results from the installation of an appliance or other item
that is installed in only one particular make and model of aircraft,
the AD is issued so that it is applicable to the aircraft, rather than
the item. The reason for this is simple: Making the AD applicable to
the airplane model on which the item is installed ensures that
operators of those airplanes will be notified directly of the unsafe
condition and the action required to correct it. While it is assumed
that an operator will know the models of airplanes that it operates,
there is a potential that the operator will not know or be aware of
specific items that are installed on its airplanes. Therefore, calling
out the airplane model as the subject of the AD prevents ``unknowing
non-compliance'' on the part of the operator. The FAA recognizes that
there are situations when an unsafe condition exists in an item that is
installed in many different aircraft. In those cases, the FAA considers
it impractical to issue AD's against each aircraft; in fact, many
times, the exact models and numbers of aircraft on which the item is
installed may not be known. Therefore, in those situations, the AD is
issued so that it is applicable to the item; furthermore, those AD's
usually indicate that the item is known to be installed on, but not
limited to, various aircraft models.
[[Page 51710]]
In light of this, since the FAA is aware that the outflow/safety
valves having the particular part numbers specified in this AD are
installed only on the Learjet airplanes identified in the applicability
of this AD, the FAA finds it appropriate in this case to issue the AD
against the airplane. The FAA may consider addressing outflow/safety
valves having other part numbers in subsequent rulemaking actions,
applicable to the airplanes on which the valves are installed.
The commenter also requests that certain Learjet service bulletins
and the address for obtaining those service bulletins be cited in lieu
of the Allied Signal Aerospace service bulletins cited in the proposal.
The commenter indicates that Allied Signal Aerospace does not mail
their service bulletins to operators of Learjet airplanes. The
commenter also points out that the Learjet service bulletins transmit
the same Allied Signal Aerospace service bulletins referenced in the
AD. The commenter also indicates that the Allied Signal Aerospace
service bulletins do not describe procedures for replacement of certain
outflow/safety valves; therefore, the commenter has submitted a
suggested rewrite of the service bulletin description that appeared in
the preamble of the proposed rule. Learjet contends that its service
bulletins more accurately define the serial numbers of the airplanes on
which suspect valves may be installed, and includes those serial
numbers in a suggested rewrite of the applicability of the AD. Finally,
the commenter adds that the Learjet service bulletins were approved by
the FAA as an alternative method of compliance with AD 94-26-01.
The FAA concurs partially. In AD 94-26-01, the FAA cited the Allied
Signal Aerospace service bulletins as the appropriate sources of
service information; those citations were appropriately carried over
into this AD. As explained in the preamble to the proposal, the FAA
also reviewed and approved the Learjet service bulletins discussed by
the commenter. While the Allied Signal Aerospace service bulletins do
not contain specific procedures for replacement of the outflow/safety
valves, those service bulletins do refer operators to the ``airplane
manufacturer's instructions'' for the replacement procedures.
Therefore, the Allied Signal Aerospace service bulletins are considered
appropriate sources of service information for accomplishing the
replacement.
In light of the commenter's remarks, however, the FAA has
determined that the actions required by this AD may be accomplished in
accordance with the procedures described in the Learjet service
bulletins as well as the Allied Signal Aerospace service bulletins.
Therefore, the final rule has been revised to reference both service
information sources. In addition, the address for obtaining the Learjet
service bulletins also has been added to the Addresses section of the
preamble to this final rule. Further, the FAA has included in the
applicability of this AD references to the Learjet service bulletins as
sources for identification of airplane serial numbers on which suspect
valves may be installed. (The applicability of the AD continues to
reference the Allied Signal Aerospace service bulletins as the
appropriate sources for identification of the affected outflow/safety
valves.)
Learjet asks that the product identification statement (after the
heading ``Airworthiness Directives'' at the beginning of the preamble
to the rule) be reworded from ``Learjet Model 24, 25, 31, 35, 36, and
55 Series Airplanes, and Learjet Model 28 and 29 Airplanes'' to
``Certain Learjet Model 24, 25, 31, 35, and 36 and All Model 28, 29,
and 55 Series Airplanes.'' Learjet suggests that similar wording should
appear throughout the rule. The FAA concurs partially. The product
identification statement at the beginning of the preamble of an AD
simply denotes the name of the type certificate holder or product
manufacturer and the model designations of the affected airplanes. The
FAA does not generally include the words ``certain'' or ``all'' in that
statement; it is kept to a minimal length. However, the preamble of the
final rule has been revised to include the commenter's suggested
change. Further, the FAA infers from Learjet's request that its
airplanes should be designated as ``series'' airplanes; therefore, the
final rule has been revised accordingly.
Learjet also requests that the statement of unsafe condition that
relates to AD 94-26-01, which appeared in the Summary section of the
preamble of the proposed rule, be revised. The proposed rule indicates
that the actions specified by AD 94-26-01 are intended to ``prevent
cracking and subsequent failure of the outflow/safety valves, which
could result in rapid decompression of the airplane.'' The commenter
suggests that the actions specified by that AD are intended to ``limit
the airplane operating altitude due to a possible failure of the
outflow/safety valves, which could result in rapid decompression of the
airplane.'' The FAA concurs with the commenter's request, and has
revised the wording throughout the final rule accordingly.
Learjet also requests clarification of a paragraph that appeared in
the preamble of the proposal that explains ``Note 1'' of the AD. That
Note discusses the legal effect of AD's on airplanes that are
identified in the applicability provision of the AD, but that have been
altered or repaired in the area addressed by the AD. Learjet asks if
this paragraph addresses aircraft that no longer meet the original type
design.
Although every effort was made to keep the language simple and
clear in the paragraph referenced by the commenter, the FAA finds it
apparent that some additional explanation is necessary to clarify for
this commenter its intent. The paragraph referenced by the commenter
merely explains the reason for the FAA's decision to include Note 1 in
this AD. It does not change the substance of either the Note or of the
regulatory effect of an AD, which the note is intended to explain. In
response to the specific question posed by the commenter, in a literal
sense, airplanes that have been altered ``no longer meet the original
type design.'' However, as the Note states, that fact is irrelevant to
the question of whether any airplane is subject to the AD; the
applicability statement of the AD stands on its own.
Learjet also requests that the economic impact information
presented in the preamble to the proposal be revised to reflect the
most current data available with regard to number of affected
airplanes. Learjet indicates that there are approximately 1,333
airplanes of the affected design in the worldwide fleet, and that 840
of those airplanes are on the U.S. Register. Learjet also suggests that
the AD reflect an estimate of 3 work hours that will be necessary for
operators to inspect the outflow/safety valves installed on its
airplanes. The commenter also suggests that proposed paragraph (b) be
rewritten to include a requirement to inspect the outflow/safety valves
to determine their part number.
The FAA concurs partially. The FAA has revised the total number of
airplanes affected by this AD, as suggested by the commenter. However,
the FAA does not find it necessary to include an additional requirement
for an inspection to determine the part number of the outflow/safety
valves, since the applicability of the AD indicates that it applies
only to those airplanes having outflow/safety valves that are
identified in certain Allied Signal Aerospace service bulletins. The
FAA acknowledges that it will be necessary for an operator to determine
if this AD applies to its fleet, and has
[[Page 51711]]
revised the economic impact information, below, to add 3 work hours to
the cost estimate, as suggested by the commenter, to account for
determining if the specific part-numbered valves are installed.
Learjet also asks that the economic impact information be revised
to specify that Allied Signal Aerospace is the appliance manufacturer.
The FAA concurs, and has revised the information accordingly.
Learjet requests that the final paragraph of the economic impact
information also be revised to specify that operators should already
have complied with the AFM revision required by AD 94-26-01. The FAA
concurs, and has revised the economic impact information accordingly.
Learjet also questions two paragraphs that appear in the preamble
of the proposal. The first paragraph indicates that the AD does not
warrant preparation of a Federalism Assessment; the second concerns the
determination of the rule's economic impact on small entities
(``regulatory flexibility''). The commenter suggests that a review of
these two paragraphs may be necessary in light of the revised number of
airplanes affected by the AD.
The FAA does not concur with the commenter's suggestion. Concerning
the paragraph pertaining to the Federalism Assessment, Executive Order
12612 requires that every rule be assessed for its impact on state and
local governments. In general, AD's will not have an effect on other
government entities because the regulation of aviation is federally
preempted by statute. State and local government are not delegated the
authority to regulate aviation; therefore, there are no ``parallel''
local regulations that could be impacted by an AD. The paragraph
concerning the Federalism Assessment is included in this rule merely to
explain this required finding.
Regarding regulatory flexibility findings, very few AD's will ever
reach the level of having a ``significant economic impact, positive or
negative, on a substantial number of small entities,'' since either
most aircraft operators do not meet the agency's criteria for small
entities, or because the cost of an individual AD usually does not
exceed the agency limit for significant impact. A statement concerning
the impact, or lack of it (as in the case of this AD), is required to
be included in the certification statement of each AD.
Learjet also asks that paragraph (a) of the proposal be revised so
that the effective date of the AD is stated as ``Within 30 days after
the effective date of this AD (if not previously accomplished per AD
94-26-01, amendment 39-9097) ....'' The FAA concurs partially. The
requirement of paragraph (a) of this AD was required previously by AD
94-26-01 to be accomplished within 30 days after January 3, 1995, which
is the effective date of that AD. Paragraph (a) of this AD merely
restates the requirements of paragraph (a) of the existing AD. As
allowed by the phrase, ``unless accomplished previously,'' which
appears in the ``Compliance'' statement of the AD, if the requirement
of paragraph (a) of that AD has already been accomplished, this final
rule does not require that those actions be repeated. Therefore, the
FAA finds it unnecessary to revise the compliance time specified in
paragraph (a) of the final rule. However, to eliminate any confusion
that may exist, the FAA has added a note to the final rule to clarify
its intent with regard to restating paragraph (a) of AD 94-26-01.
Learjet also indicates that the requirement of paragraph (a) could
be accomplished by inserting a copy of Learjet Temporary Flight Manual
(TFM) Change 94-14, dated January 9, 1995 (for Model 24 series
airplanes), or TFM Change 94-15, dated January 9, 1995 (for all models,
including Model 24 series airplanes), into the AFM. The FAA concurs and
has included a note after paragraph (a) of the final rule to reflect
this information.
After careful review of the available data, including the comments
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule with the changes previously
described. The FAA has determined that these changes will neither
significantly increase the economic burden on any operator nor increase
the scope of the AD.
There are approximately 1,333 Model 24, 25, 28, 29, 31, 35, 36, and
55 series airplanes of the affected design in the worldwide fleet. The
FAA estimates that 840 airplanes of U.S. registry will be affected by
this proposed AD.
The AFM revision currently required by AD 94-26-01 takes
approximately 1 work hour per airplane to accomplish, at an average
labor rate of $60 per work hour. Based on these figures, the total cost
impact associated with the current AFM revision requirement of AD 94-
26-01 on U.S. operators is estimated to be $50,400, or $60 per
airplane.
However, based on information provided by the manufacturer, and
based on the effective date of AD 94-26-01, the FAA assumes that the
majority of U.S. operators will have already accomplished the AFM
revision requirement. Therefore, any future economic impact of this AD
can be assumed to be less than the ``total cost impact'' figure
indicated above.
The removal and replacement of parts that are required by this new
AD will take approximately 15 work hours per airplane to accomplish, at
an average labor rate of $60 per work hour. (This estimate includes 3
work hours that are required to determine the valve serial number.)
However, Allied Signal (the appliance manufacturer) advises that it
will reimburse operators for the costs of removal and replacement.
Therefore, based on this information, the total cost impact associated
with determining the valve serial number is estimated to be $151,200,
or $180 per airplane. (U.S. operators will incur no cost impact for the
removal and replacement requirements.) This total cost impact figure is
based on assumptions that no operator has yet accomplished these new
requirements of this AD action, and that no operator would accomplish
those actions in the future if this AD were not adopted.
The regulations adopted herein will not have substantial direct
effects 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. Therefore, in
accordance with Executive Order 12612, it is determined that this final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this action (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. A final evaluation has been prepared for this action
and it is contained in the Rules Docket. A copy of it may be obtained
from the Rules Docket at the location provided under the caption
ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends part 39 of
the
[[Page 51712]]
Federal Aviation Regulations (14 CFR part 39) as follows:
PART 39--AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40101, 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by removing amendment 39-9097 (59 FR
64844, December 16, 1994), and by adding a new airworthiness directive
(AD), amendment 39-9381, to read as follows:
95-20-03 Learjet: Amendment 39-9381. Docket 94-NM-211-AD. Supersedes
AD 94-26-01, Amendment 39-9097.
Applicability: Model 24, 25, 28, 29, 31, 35, 36, and 55 series
airplanes having airplane serial numbers listed in the Learjet
service bulletins listed below; and equipped with Allied Signal
outflow/safety valves, number 130406-1 or 102850-5, as identified in
Allied Signal Aerospace Alert Service Bulletin 130406-21-A4011,
Revision 3, dated January 5, 1995, or 102850-21-A4021, Revision 2,
dated October 6, 1994; certificated in any category:
------------------------------------------------------------------------
Service bulletin
Service bulletin reference revision level Service bulletin date
------------------------------------------------------------------------
Learjet Service Bulletin SB Original............ January 3, 1995.
24/25-21-4.
Learjet Service Bulletin SB Original............ January 3, 1995.
28/29-21-8.
Learjet Service Bulletin SB Original............ January 3, 1995.
31-21-6.
Learjet Service Bulletin SB Original............ January 3, 1995.
35/36-21-19.
Learjet Service Bulletin SB Original............ January 3, 1995.
55/21-10.
------------------------------------------------------------------------
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
modified, altered, or repaired in the area subject to the
requirements of this AD. For airplanes that have been modified,
altered, or repaired so that the performance of the requirements of
this AD is affected, the owner/operator must use the authority
provided in paragraph (d) of this AD to request approval from the
FAA. This approval may address either no action, if the current
configuration eliminates the unsafe condition; or different actions
necessary to address the unsafe condition described in this AD. Such
a request should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
case does the presence of any modification, alteration, or repair
remove any airplane from the applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
Note 2: Paragraph (a) of this AD merely restates the
requirements of paragraph (a) of AD 94-26-01, amendment 39-9097. As
allowed by the phrase, ``unless accomplished previously,'' if those
requirements of AD 94-26-01 have already been accomplished, this AD
does not require that those actions be repeated.
To prevent rapid decompression of the airplane due to cracking
and subsequent failure of certain outflow/safety valves, accomplish
the following:
(a) Within 30 days after January 3, 1995 (the effective date of
AD 94-26-01, amendment 39-9097), revise the Limitations Section of
the FAA-approved Airplane Flight Manual (AFM) to include the
following. This may be accomplished by inserting a copy of this AD
in the AFM.
``Operation of the airplane at any altitude above 41,000 feet is
prohibited.''
Note 3: Inserting a copy of Learjet Temporary Flight Manual
Change 94-14, dated January 9, 1995 (for Model 24 series airplanes),
or 94-15, dated January 9, 1995 (for all models, including Model 24
series airplanes), into the AFM is considered acceptable for
compliance with the requirement of paragraph (a) of this AD.
(b) Within 18 months after the effective date of this AD,
replace the outflow/safety valves, part numbers 130406-1 and 102850-
5, as identified in Allied Signal Aerospace Alert Service Bulletin
130406-21-A4011, Revision 3, dated January 5, 1995, or 102850-21-
A4021, Revision 2, dated October 6, 1994, as applicable; or as
identified in Learjet Service Bulletin SB 24/25-21-4, SB 28/29-21-8,
SB 31-21-6, SB 35/36-21-19, or SB 55-21-10, all dated January 3,
1995, as applicable; with serviceable parts in accordance with the
procedures described in the applicable service bulletin.
Accomplishment of this replacement constitutes terminating action
for the requirement of paragraph (a) of this AD; after the
replacement has been accomplished, the previously required AFM
limitation may be removed.
(c) As of January 3, 1995 (the effective date of AD 94-26-01,
amendment 39-9097), no person shall install an outflow/safety valve,
part number 130406-1 or 102850-5, as identified in Allied Signal
Aerospace Alert Service Bulletin 130406-21-A4011, Revision 3, dated
January 5, 1995, or 102850-21-A4021, Revision 2, dated October 6,
1994, as applicable; or as identified in Learjet Service Bulletin SB
24/25-21-4, SB 28/29-21-8, SB 31-21-6, SB 35/36-21-19, or SB 55-21-
10, all dated January 3, 1995, as applicable; on any airplane unless
that valve is considered to be serviceable in accordance with the
specifications contained in the Accomplishment Instructions of the
applicable service bulletin.
(d) An alternative method of compliance or adjustment of the
compliance time that provides an acceptable level of safety may be
used if approved by the Manager, Los Angeles Aircraft Certification
Office (ACO), FAA, Transport Airplane Directorate. Operators shall
submit their requests through an appropriate FAA Principal
Maintenance Inspector, who may add comments and then send it to the
Manager, Los Angeles ACO.
Note 4: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Los Angeles ACO.
(e) Special flight permits may be issued in accordance with
sections 21.197 and 21.199 of the Federal Aviation Regulations (14
CFR 21.197 and 21.199) to operate the airplane to a location where
the requirements of this AD can be accomplished.
(f) The replacement shall be done in accordance with Allied
Signal Aerospace Alert Service Bulletin 130406-21-A4011, Revision 3,
dated January 5, 1995; Allied Signal Aerospace Alert Service
Bulletin 102850-21-A4021, Revision 2, dated October 6, 1994; Learjet
Service Bulletin SB 24/25-21-4, dated January 3, 1995; Learjet
Service Bulletin SB 28/29-21-8, dated January 3, 1995; Learjet
Service Bulletin SB 31-21-6, dated January 3, 1995; Learjet Service
Bulletin SB 35/36-21-19, dated January 3, 1995; or Learjet Service
Bulletin SB 55-21-10, dated January 3, 1995; as applicable. The
incorporation by reference of Allied Signal Aerospace Alert Service
Bulletin 102850-21-A4021, Revision 2, dated October 6, 1994, was
approved previously by the Director of the Federal Register in
accordance with 5 U.S.C. 552(a) and 1 CFR part 51 as of January 3,
1995 (59 FR 64844). The incorporation by reference of the remainder
of the documents listed was approved by the Director of the Federal
Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.
Copies may be obtained from Allied Signal, Inc., Controls &
Accessories, 11100 N. Oracle Road, Tucson, Arizona 85737-9588;
telephone (602) 469-1000; and Learjet, Inc., P.O. Box 7707, Wichita,
Kansas 67277-7707. Copies may be inspected at the FAA, Transport
Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or
at the FAA, Los Angeles Aircraft Certification Office, Transport
Airplane Directorate, 3960 Paramount Boulevard, Lakewood,
California; or at the Office of the Federal Register, 800 North
Capitol Street, NW., suite 700, Washington, DC.
(g) This amendment becomes effective on November 2, 1995.
Issued in Renton, Washington, on September 20, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-23811 Filed 10-2-95; 8:45 am]
BILLING CODE 4910-13-U
