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[Federal Register Volume 66, Number 82 (Friday, April 27, 2001)]
[Rules and Regulations]
[Pages 21077-21081]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-10337]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-276-AD; Amendment 39-12205; AD 2001-08-28]
RIN 2120-AA64

Airworthiness Directives; Boeing Model 767 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Boeing Model 767 series airplanes, that requires 
revising the Airworthiness Limitations Section of the maintenance 
manual (767 Airworthiness Limitations Instructions (ALI)). The revision 
will incorporate into the ALI certain inspections and compliance times 
to detect fatigue cracking of principal structural elements (PSE). This 
amendment is prompted by analysis of data that identified specific 
initial inspection thresholds and repetitive inspection intervals for 
certain PSE's to be added to the ALI. The actions specified by this AD 
are intended to ensure that fatigue cracking of various PSE's is 
detected and corrected; such fatigue cracking could adversely affect 
the structural integrity of these airplanes.

DATES: Effective June 1, 2001.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of June 1, 2001.

ADDRESSES: The service information referenced in this AD may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the Federal 
Aviation Administration (FAA), Transport Airplane Directorate, Rules 
Docket, 1601 Linda Avenue, SW., Renton, Washington; or at the Office of 
the Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.

FOR FURTHER INFORMATION CONTACT: John Craycraft, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue SW., Renton, Washington; telephone (425) 227-2782; fax 
(425) 227-1181.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to certain Boeing Model 767 series 
airplanes was published in the Federal Register on January 28, 1999 (64 
FR 4372). That action proposed to require revising the Airworthiness 
Limitations Section of the maintenance manual (767 Airworthiness 
Limitations Instructions (ALI)). The revision would incorporate

[[Page 21078]]

into the ALI certain inspections and compliance times to detect fatigue 
cracking of principal structural elements (PSE).

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Support for the Notice of Proposed Rule Making (NPRM)

    One commenter supports the NPRM.

1. Request To Use the Term Structural Significant Item (SSI) Rather 
Than ``Principal Structural Elements (PSE)''

    One commenter requests that a clarifying note be added to the 
preamble of the proposal to explain why the term ``PSE'' is used in the 
NPRM, rather than ``SSI,'' as used in the Boeing 767 Maintenance 
Planning Document (MPD). The commenter states that such a note may 
avoid confusion between the use of the terms.
    The FAA agrees that some clarification is necessary. We acknowledge 
that SSI's are a subset of PSE's, however, the Federal Aviation 
Regulations (FAR) related to damage tolerance refer only to PSE's. 
Therefore, for the purposes of this AD, we consider the two terms 
interchangeable. A new Note 3 has been added to the final rule to 
clarify this information.

2. Request To Specify Proper MPD Subsection

    One commenter, the manufacturer, notes that the reference in the 
NPRM to ``Chapter B'' of Section 9 of Boeing 767 MPD is incorrect. The 
commenter states that the correct title is ``Subsection B.''
    The FAA agrees and has revised the final rule accordingly.

3. Request To Limit the Applicability of the NPRM

    One commenter requests that the applicability of the NPRM be 
revised to specifically exclude Boeing Model 767-300F (freighter) 
series airplanes.
    The FAA agrees that clarification to specifically exclude Model 
767-300F airplanes is necessary. The preamble of the NPRM specified 
that Model 767-300F freighter airplanes are not considered to be part 
of the applicability of this AD since the revision of the ALI that was 
in effect at the time of the first delivery of a Model 767-300F 
freighter already addressed the need for inspections of PSE's. However, 
to ensure the clarity of this exclusion, we have added a new Note 1 to 
the final rule specifying that Model 767-300F freighter airplanes are 
not affected by this AD.

4. Requests Regarding Interpretation of Need for an Alternative 
Method of Compliance

    One commenter requests that, prior to the issuance of the final 
rule, the manufacturer be required to develop certain fatigue 
thresholds and damage tolerance analysis on all repairs installed per 
Boeing documents (e.g., service bulletins, structural repair manuals 
(SRM's), etc.). The commenter explains that it interprets the language 
of Note 1 of the NPRM to mean that, for any repairs found on SSI's 
during the initial or repeat inspections, the operator would be 
required to evaluate the repair, obtain a recommendation from a damage 
tolerance-certified Designated Engineering Representative, take 
corrective action, and obtain AMOC approval before returning an 
airplane to service. The commenter adds that the time involved for 
accomplishing those actions would inevitably result in extended down-
time for the affected airplane, even though the existing repairs were 
previously FAA-approved. Another commenter expresses concern that any 
repairs or modifications to the SSI's would automatically require AMOC 
approval and suggests that only those repairs or modifications that 
prevent the operator from performing the inspections would need to 
apply for an AMOC. That same commenter also expresses concern about the 
length of time it takes for approval of AMOC's. The commenter requests 
that, instead of applying for an AMOC, the repair be analyzed for 
static strength, with a damage tolerance analysis to follow within one 
year.
    The FAA does not agree with the commenter's request to require that 
the manufacturer be required to develop, prior to the issuance of the 
final rule, certain fatigue thresholds and damage tolerance analyses on 
all repairs installed per Boeing documents (e.g., service bulletins, 
SRM's, etc.). Boeing Model 767 series airplanes are certified to be 
damage tolerant; therefore, repairs to these airplanes are also 
required to be damage tolerant. With the addition to the maintenance 
manual of the ALI's specified in this AD, both the original Model 767 
structure and the repairs described in the 767 SRM are fully damage 
tolerant and comply with the applicable provisions of 14 CFR 25.571. If 
an operator chooses to seek an extension of the inspection thresholds 
for certain repairs, it may do so per paragraph (c) of this AD. No 
change is necessary to the final rule in this regard.
    However, the FAA considers that some information contained in Note 
2 of the final rule should be clarified to accommodate certain 
airplanes that are required to have ALI's included in the maintenance 
program. Therefore, Note 2 (which revises Note 1 of the NPRM) of this 
final rule addresses airplanes that have been previously modified, 
altered, or repaired in the areas addressed by certain ALS inspections. 
Such modifications, alterations, or repairs may prevent the operator 
from being able to accomplish the specified inspections. We have 
provided guidance for this determination in Advisory Circular (AC) 25-
1529. If the requirements of an AD cannot be performed, then operators 
must submit a request for an approval of an AMOC from the FAA, in 
accordance with the provision of paragraph (c) of this final rule. The 
new Note 2 of this AD is to clarify when an AMOC would be required.

5. Requests To Revise Paragraph (a) of the NPRM

    One commenter, the manufacturer, reiterates that the NPRM would 
require that Section 9 of the MPD be revised to incorporate Chapter B. 
The commenter concludes that, since the manufacturer is the author of 
Section 9 of the MPD and has already incorporated Subsection B (the 
correct title of that section, rather than ``Chapter B''), it is 
unnecessary to require that action to be accomplished by the issuance 
of an AD. Another commenter, an airline operator, states that revising 
the manufacturer's document is contrary to long-standing industry 
practices, whereby companies do not revise documents that are created, 
published, and maintained by other companies. Rather, as the 
manufacturer points out, Section 9 of the MPD is the manufacturer's 
responsibility, not the operators'.
    The FAA does not agree. The airworthiness limitations, like the 
operating limitations, are a part of the type certificate for an 
airplane. Once an airworthiness certificate is issued for an airplane 
certifying that it conforms to an approved type design, this design is 
``locked'' in the sense that the manufacturer cannot unilaterally 
change it for the subject airplane. Therefore, when the manufacturer 
makes any subsequent changes to the type certificate, including changes 
to the operating or airworthiness limitations, those changes are 
legally required only for products that are submitted for airworthiness 
certification based on a showing of conformity to the later design.

[[Page 21079]]

    Thus, for many years, the FAA has imposed operating restrictions 
that are necessary to address identified unsafe conditions by requiring 
revisions to the operating limitations section of the Airplane Flight 
Manual (AFM). (Revision of the AFM by the type certificate holder would 
be effective only for airplanes produced after that revision.) 
Similarly, Boeing's revision to the ALI was effective only for 
airplanes later certificated with those revisions included in their 
type certificate. For this reason, as stated in the NPRM, we must 
engage in rulemaking (i.e., issuance of an AD), in order to make the 
revisions mandatory for previously certificated airplanes.
    While the ALI's are contained in a ``Boeing document'' in the sense 
that Boeing originally produced it, the document, nevertheless, is a 
part of the instructions for continued airworthiness that operators 
must use to maintain the airplane properly. As explained in the NPRM, 
the effect of requiring that the document be revised to incorporate the 
current version of the ALI is that, in accordance with 14 CFR part 
91.403(c), operators are then required to comply with those 
limitations. This is analogous to the effect of requiring a revision to 
the operating limitations: in accordance with 14 CFR Part 91.9(a), 
operators are required to comply with the revised operating 
limitations.
    Of course, those operators that have previously revised the ALI (or 
incorporated the revision into their maintenance programs) are given 
credit for having previously accomplished the requirements of this AD, 
as allowed by the phrase, ``unless accomplished previously.'' The legal 
effect is the same: the operator is required to comply with the 
limitations per 14 CFR part 91.403(c).

6. Request To Clarify Intent of the NPRM

    One commenter states that paragraph (b) of the NPRM appears to 
conflict with the original intent of the NPRM. Paragraph (b) of the 
NPRM specifies that, after revising the MPD in accordance with 
paragraph (a) of the NPRM, no alternative inspections or inspection 
intervals shall be approved for the PSE's. The commenter explains that 
it is not clear why paragraph (b) is needed if the inspections were 
accomplished in accordance with 14 CFR parts 43 and 91. The commenter 
states that paragraph (b) of the NPRM essentially defeats the stated 
purpose of the NPRM, which is to have operators record their AD 
compliance only once (at the time the operator's maintenance program is 
changed), in order to reduce the burden of record keeping and tracking. 
Second, the commenter explains that paragraph (b) of the NPRM further 
conflicts with the stated purpose of the NPRM since the ALI itself 
allows operators certain flexibility in inspection methods and 
repetitive intervals (although not for initial inspection thresholds) 
through the use of Boeing's Damage Tolerance Rating (DTR) system.
    The FAA does not agree. The purpose of this AD is to address the 
identified unsafe condition of fatigue cracking in certain PSE's. We 
have determined that, in order to accomplish that purpose, those 
airplanes must be brought into compliance with the certification basis, 
i.e., 14 CFR part 25.571, amendment 25-45. We point out that paragraph 
(b) of the final rule merely repeats and enforces the provision 
presently existing in the Boeing 767 MPD, which requires any revision 
of the airworthiness limitations to be approved by the Seattle Aircraft 
Certification Office, FAA. We consider that paragraph (b) of the final 
rule, therefore, does not conflict with the intention to have 
operator's record their AD compliance only once. Additionally, this AD 
does not specifically address (or restrict) the use of the DTR 
specified in the ALI. No change is necessary to the final rule in this 
regard.

7. Request To Provide Further Clarification Regarding Flight Cycles 
vs. Flight Hour Thresholds

    One commenter, the airplane manufacturer, states that, since there 
is reference to the 25,000 flight cycle threshold and 50,000 flight 
cycle threshold (in the preamble of the NPRM), it should also be noted 
that there is a flight cycle versus flight hour threshold for some 
flight length sensitive items. Also, the commenter notes that there are 
some other restrictions, such as a calendar threshold of 20 years 
unless an FAA-approved Corrosion Prevention and Control Program (CPCP) 
has been implemented, as well as a requirement to revert any escalated 
structural inspections back to the intervals specified in Section 8 of 
the MPD.
    The FAA acknowledges that there is other information available in 
the revision to the MPD, which was not discussed in the preamble of the 
NPRM in the section entitled ``New Revision of ALI.'' The information 
that we provided in the preamble of the NPRM was intended to be 
representative of the information that was used to determine that none 
of the airplanes affected is likely to reach the threshold for certain 
PSE's (identified as SSI's in the ALI). Since the ``New Revision of 
ALI'' section does not reappear in the final rule, no change to the 
final rule is necessary in this regard.

8. Request To Revise Certain SSI Repairs

    One commenter requests that the requirements of the NPRM be revised 
to reflect certain repair actions for SSI's that were installed before 
the effective date of the AD, and certain other repair actions for 
SSI's that are installed after the effective date of the AD.
    The FAA does not agree that the requirements of the NPRM should be 
revised. In the case of this final rule, the required action is simply 
to revise Section 9 of the Model 767 MPD by incorporating Subsection B, 
dated August 1997. The specific information contained in the MPD is 
developed (with the concurrence of the FAA) and then printed by the 
manufacturer. The FAA notes that the requirements of this AD do not 
address the accomplishment of the specific information contained in 
Subsection B. As discussed previously, 14 CFR 91.403(c) imposes that 
requirement, and NOTE 2 has been added to the AD to addresss the 
possible need to obtain approval of alternative methods of compliance 
for certain repairs. Therefore, no further change to the final rule is 
necessary in this regard.

9. Request To Extend the Compliance Time

    One commenter, an operator, requests that the compliance time be 
revised from ``within 3 years after the effective date of the AD'' to 
``within 4 years after the effective date of the AD.'' The commenter 
states that the manufacturer originally recommended a compliance time 
of 5 years and, consequently, the commenter has been using a 5-year 
compliance time in its maintenance planning activities. The commenter 
states that a 3-year grace period would cause excessive airplane 
downtimes and lost revenue costs.
    The FAA does not agree with the commenter's request to extend the 
compliance time. For the reasons discussed in the preamble of the NPRM, 
this AD allows operators up to 3 years after the effective date of this 
AD to accomplish the ALI revision required by this AD. This period 
provides operators of airplanes that are approaching or have already 
reached the 25,000-flight-cycle inspection threshold with a reasonable 
amount of time to plan and perform the inspections. We note that only a 
few PSE's in the ALI have an initial inspection threshold of 25,000 
total flight cycles. The majority of PSE's in the ALI have an initial 
inspection

[[Page 21080]]

threshold that corresponds to the design service objective of the 
affected airplane (i.e., 50,000 total flight cycles for passenger 
airplanes). In addition, the Model 767 Structures Working Group, whose 
membership is composed of many of the major operators worldwide and 
almost all U.S. operators, has been aware of the specific contents and 
requirements of this ALI revision since August 1996. These facts have 
led us to determine that 3 years is an appropriate and reasonable 
period of time for operators to comply with the requirements of this 
AD. However, an alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
requested in accordance with paragraph (c) of this AD.

10. Requests To Require Incorporation of ALI Into Operations 
Specifications

    One commenter, the manufacturer, suggests that the NPRM be revised 
to require the operators to incorporate the ALI's into the appropriate 
Maintenance Program Specification (Operations Specification).
    The FAA does not agree that incorporation of the ALI's into the 
Operations Specifications (Ops Specs) is appropriate. Operation of 
certain transport airplanes may be exclusively under the provisions and 
requirements of Part 91, and therefore, operators would not even be 
required to maintain Operations Specifications. Further, Ops Specs 
simply authorize the use of a Continuous Airworthiness Maintenance 
Program (CAMP) for the operator's individual airplane models and 
specify, in particular, that procedures, standards, checks, service, 
repair, and/or preventive maintenance, checks or tests, shall be 
described in the certificate holder's manual.
    The commenter further requests that the requirements of the NPRM be 
written such that the operator's Operations Specification is 
continuously updated with the current revision of Section 9 of the MPD. 
If that process is not possible, the commenter suggests that the 
requirements be accomplished in accordance with the latest FAA-approved 
revision of Section 9 of the MPD.
    The FAA does not agree with the commenter's requests. We note that 
the commenter provided no justification or benefit of implementing the 
suggested changes. In response to the suggestion that the Ops Specs be 
continuously updated with current revisions of Section 9 of the MPD, 
the FAA notes that incorporation of new revisions of the ALI into the 
Ops Specs would have the effect of imposing new requirements without 
providing notice to the public and opportunity for comment.
    For a similar reason, to change paragraph (a) of this AD to 
incorporate any revision of Boeing Document D622T001-9 other than the 
``June 1997'' (as specified in the NPRM), also would have the effect of 
imposing new requirements without providing notice to the public and 
opportunity for comment. We consider that delaying this action to 
provide for such notice to the public would be inappropriate since we 
have determined that an unsafe condition exists, and that inspections 
must be conducted to ensure continued safety. However, paragraph (c) of 
the final rule does provide affected operators the opportunity to 
request approval of an alternative method of compliance.

Editorial Changes Appearing in the Final Rule

    To accommodate the addition of the new notes in the final rule, the 
FAA has revised the numbering of the notes that appeared in the NPRM.

Conclusion

    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 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    There are approximately 660 Boeing Model 767 series airplanes 
(excluding Model 767-300F freighters) of the affected design in the 
worldwide fleet. The FAA estimates that 250 airplanes of U.S. registry 
will be affected by this AD, that it will take approximately 1 work 
hour per airplane to accomplish the required actions, and that the 
average labor rate is $60 per work hour. Based on these figures, the 
cost impact of the AD on U.S. operators is estimated to be $15,000, or 
$60 per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the requirements of this AD 
action, and that no operator would accomplish those actions in the 
future if this AD were not adopted.
    Although this AD requires only a revision to the current ALI, the 
FAA recognizes that the inspections contained in the ALI will then be 
required by 14 CFR parts 43 and 91. We estimate that it will take 
approximately 1,000 work hours to accomplish all of the ALI 
inspections. At an average labor rate of $60 per work hour, the cost to 
perform the ALI inspections (14 CFR parts 43 and 91, rather than by 14 
CFR part 39) will be approximately $60,000 per airplane. We note that 
the majority of work hours needed to perform the inspections will be 
expended when an affected airplane reaches the 50,000 flight-cycle-
threshold. Based upon current airplane utilization, we estimate that no 
airplane will reach this threshold for at least 10 years.

Regulatory Impact

    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 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), 40113, 44701.

Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

[[Page 21081]]

2001-08-28  Boeing: Amendment 39-12205. Docket 97-NM-276-AD.

    Applicability: Model 767-200 and -300 series airplanes having 
line numbers 1 through 669 inclusive, certificated in any category.

    Note 1: Boeing Model 767-300F freighter airplanes are not 
affected by this AD.

    Note 2: This AD requires revisions to certain operator 
maintenance documents to include new inspections. Compliance with 
these inspections is required by 14 CFR part 91.403(c). For 
airplanes that have been previously modified, altered, or repaired 
in the areas addressed by these inspections, the operator may not be 
able to accomplish the inspections described in the revisions. In 
this situation, to comply with 14 CFR part 91.403(c), the operator 
must request approval for an alternative method of compliance in 
accordance with paragraph (c) of this AD. The request should include 
a description of changes to the required inspections that will 
ensure the continued damage tolerance of the affected structure. The 
FAA has provided guidance for this determination in Advisory 
Circular (AC) 25-1529.

    Compliance: Required as indicated, unless accomplished 
previously.
    To ensure continued structural integrity of these airplanes, 
accomplish the following:

Revise Section 9 of the Boeing 767 Maintenance Planning Data (MPD)

    (a) Within 3 years after the effective date of this AD, revise 
Section 9 of the Boeing 767 Maintenance Planning Data (MPD) Document 
entitled ``Airworthiness Limitations and Certification Maintenance 
Requirements (CMR's)'' to incorporate Subsection B of Boeing 
Document D622T001-9, Revision ``June 1997.''

    Note 3: The referenced Subsection B contains a requirement that 
cracks found during the specified inspections be reported to the 
Seattle Aircraft Certification Office (ACO), FAA. Information 
collection requirements contained in this regulation have been 
approved by the Office of Management and Budget under the provisions 
of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501, et seq.) and 
have been assigned OMB Control Number 2120-0056.

    Note 4: For the purposes of this AD, the terms Principal 
Structural Elements (PSE's) as used in this AD, and Structural 
Significant Items (SSI's) as used in Section 9 of Model 767 MPD 
Document, are considered to be interchangeable.

Alternative Inspections and Inspection Intervals

    (b) Except as provided in paragraph (c) of this AD: After the 
actions required by paragraph (a) of this AD have been accomplished, 
no alternative inspections or inspection intervals shall be approved 
for the SSI's contained in Boeing 767 MPD Document D622T001-9, 
Revision ``June 1997.''

Alternative Methods of Compliance

    (c) 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, Seattle ACO. Operators shall submit 
their requests through an appropriate FAA Principal Maintenance 
Inspector, who may add comments and then send it to the Manager, 
Seattle ACO.

    Note 5: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permits

    (d) 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.

Incorporation by Reference

    (e) The actions shall be done in accordance with Subsection B of 
Boeing 767 Maintenance Planning Data Document D622T001-9, Revision 
``June 1997'', which contains the following list of effective pages:

------------------------------------------------------------------------
                 Page No.                   Revision date shown on page
------------------------------------------------------------------------
List of Effective Pages, Page 9.0-5......  June 1997.
------------------------------------------------------------------------

    This incorporation by reference 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 Boeing Commercial Airplane 
Group, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be 
inspected at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington; or at the Office of the Federal 
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Effective Date

    (f) This amendment becomes effective on June 1, 2001.

    Issued in Renton, Washington, on April 19, 2001.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-10337 Filed 4-26-01; 8:45 am]
BILLING CODE 4910-13-P
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