[Federal Register Volume 72, Number 40 (Thursday, March 1, 2007)]
[Proposed Rules]
[Pages 9276-9281]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-3561]


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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-23072; Directorate Identifier 2005-NE-38-AD]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney JT9D-7R4 Turbofan 
Engines

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

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: The FAA proposes to supersede an existing airworthiness 
directive (AD) for Pratt & Whitney (PW) JT9D-7R4 turbofan engines. That 
AD currently requires inspection of the blade root thickness of 1st 
stage fan blades identified by part number (P/N) and serial number (SN) 
in the AD. This proposed AD would require the same actions but would 
correct 12 P/Ns, add 10 part SNs, and add the definition of next fan 
blade exposure to the compliance section. This proposed AD results from 
the discovery of inaccurate part quantity, part numbers, and serial 
numbers used in AD 2005-26-09. We are proposing this AD to prevent 1st 
stage fan blade fracture and uncontained engine failure, resulting in 
possible damage to the airplane.

DATES: We must receive any comments on this proposed AD by April 30, 
2007.

ADDRESSES: Use one of the following addresses to comment on this 
proposed AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590-0001.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Kevin Donovan, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
238-7743, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments regarding this proposal. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2005-23072; 
Directorate Identifier 2005-NE-38-AD'' in the subject line of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed AD. We will 
consider all comments received by the closing date and may amend the 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this proposed AD. Using the search function of the 
DMS Web site, anyone can find and read the comments in any of our 
dockets, including the name of the individual who sent the comment (or 
signed the comment on behalf of an association, business, labor union, 
etc.). You may review the DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78) or you 
may visit http://dms.dot.gov.

Examining the AD Docket

    You may examine the docket that contains the proposal, any comments 
received and any final disposition in person at the Docket Management 
Facility between 9 a.m. and 5 p.m., Monday through Friday, except 
Federal holidays. The Docket Office (telephone (800) 647-5227) is 
located on the plaza level of the Department of Transportation Nassif 
Building at the street address stated in ADDRESSES. Comments will be 
available in the AD docket shortly after the DMS receives them.

Discussion

    On December 16, 2005, the FAA issued AD 2005-26-09, Amendment 39-
14430 (70 FR 76381, December 27, 2005). That AD requires inspection of 
the blade root thickness of 1st stage fan blades identified by P/N and 
SN. That AD was the result of a report of a repair station that created 
an unapproved repair on 1st stage fan blades. That condition, if not 
corrected, could result in 1st stage fan blade fracture and uncontained 
engine failure, resulting in possible damage to the airplane.

Actions Since AD 2005-26-09 Was Issued

    Since AD 2005-26-09 was issued, we received comments on the AD 
requesting clarification. We considered those requests and have changed 
the compliance section in this proposed AD for clarification. We also 
found and corrected 12 incorrect P/Ns, and added 10 part SNs of 
affected 1st stage fan blades to Table 1 of this proposed AD. The 
comments and affected P/Ns and SNs are also discussed below.

[[Page 9277]]

Request To Clarify ``At the Next 1st Stage Fan Blade Exposure''

    Two air carriers request that we clarify ``at the next 1st stage 
fan blade exposure,'' to prevent any in-service disruptions or delays. 
The commenter further states that the 1st stage fan blades can be 
exposed when:
     Some 1st stage fan blades are replaced due to in-service 
foreign object damage;
     A 1st stage fan hub is replaced and the same 1st stage fan 
blades are reused; and
     At shop visit when 1st stage fan blades are removed from 
the fan hub for cause or work scope.
    We agree with adding a paragraph to the proposed AD which defines 
next 1st stage fan blade exposure. We have defined it as when any 1st 
stage fan blade is removed from the engine; or when the 1st stage fan 
hub is removed from the engine.

Suggestion To Report When Finding Affected 1st Stage Fan Blades

    Air Canada suggests that operators finding any affected 1st stage 
fan blades should report back to the FAA. The commenter states that by 
requiring this reporting, all 520 of the blades can then be accounted 
for, and the FAA can close the AD. The commenter is also concerned that 
if some blades cannot be accounted for, such as blades already 
scrapped, misplaced, or shelved, then the AD will never be closed, and 
operators will be forced to verify the AD indefinitely at every 1st 
stage fan blade installation.
    We do not agree. This proposed AD requires a onetime inspection for 
a specific population of 1st stage fan blades. If an operator has 
inspected and verified a certain set of 1st stage fan blades in 
accordance with the proposed AD, then at the next 1st stage fan blade 
exposure, only replacement blades that are listed in Table 1 of the 
proposed AD will require inspection and verification.

Request To Clarify or Remove Paragraph (e)

    Air Canada states that compliance paragraph (e) mentions that the 
AD must be performed within the compliance times specified, but there 
are no times specified. The commenter requests this instruction be 
removed or clarified.
    We partially agree. We revised the compliance times for 
clarification in the proposed AD.

Comment That ``At Exposure'' Limit Is Not a Practical Limit

    ABX AIR claims that the ``at exposure'' limit in the AD is not 
practical. They said that ``at exposure'' will require the operators to 
set up a special inspection schedule to accomplish this onetime 
inspection which is not suitable for fleet operators.
    We partially agree. Inspecting the affected parts at the next 1st 
stage fan blade exposure is sufficient. It is not necessary for 
operators to set up a special inspection schedule since this inspection 
does not impact the FAA-approved maintenance program procedures. 
However, for clarification, we added a definition for ``next first 
stage fan blade exposure'' to the proposed AD.

Request To Clarify ``Before Installing the 1st Stage Fan Blades''

    ABX AIR requests that we clarify ``before installing the 1st stage 
fan blades'' in paragraph (f). ABX believes the AD should contain a 
concise clarifying statement such as: ``After the active date of this 
AD, no person may install, on any airplane, any blade listed in Table 1 
of this AD unless the actions of this AD have already been 
accomplished.''
    We agree. We added a prohibition statement that states that after 
the effective date of this (proposed) AD, do not install any 1st stage 
fan blades listed in Table 1 of this AD on any airplane, unless the 
actions of this AD have been done to the 1st stage fan blades.

P/Ns Corrected, and P/Ns and SNs Added

    Since we issued AD 2005-26-09, we found and corrected 12 incorrect 
P/Ns, and added 10 part SNs of affected 1st stage fan blades in Table 1 
of this proposed AD. The corrected numbers are as follows:

------------------------------------------------------------------------
                                       Corrected  P/
           Incorrect P/Ns                   Ns                SNs
------------------------------------------------------------------------
5001341-023.........................     5001341-022  JW2313
5001341-024.........................     5001341-022  JW2498
5001341-025.........................     5001341-022  JW2541
5001341-026.........................     5001341-022  JW2560
5001341-027.........................     5001341-022  JW2589
5001341-028.........................     5001341-022  JW2639
5001341-029.........................     5001341-022  JW2760
5001341-030.........................     5001341-022  JW2792
5001341-031.........................     5001341-022  MO579
5001341-032.........................     5001341-022  MG2825
5001341-033.........................     5001341-022  MG5477
5001341-034.........................     5001341-022  ND5917
------------------------------------------------------------------------

    The added part SNs are as follows:

------------------------------------------------------------------------
                 PNs                     Added  SNs
-----------------------------------------------------
5001341-022..........................          JW4713
5001341-022..........................          MG6743
5001341-022..........................          ND6924
831021-003...........................          ND9177
831021-003...........................          ND9496
831021-003...........................          NS7894
831021-003...........................          NS8559
831021-003...........................          NS9072
804121...............................          PX3805
804121...............................          PX4266
------------------------------------------------------------------------

Conclusion

    We have carefully reviewed the available data, including the 
comments received, and determined that air safety and the public 
interest require proposing this 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 
proposed AD.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other products 
of this same type design. For that reason, we are proposing this AD, 
which would require:
     Checking the 1st stage fan blade for a circled, letter I, 
on the approved marking area of the outboard side of the blade 
platform. If the blade has this marking, no further action is required.
     Removing 1st stage fan blades without a circled, letter I, 
on the approved marking area of the outboard side of the blade platform 
if installed; and
     Inspecting the 1st stage fan blade root thickness; and
     Returning to service 1st stage fan blades that pass the 
inspection, after properly marking the blade.

Costs of Compliance

    We estimate that this proposed AD would affect 531 1st stage fan 
blades installed on JT9D-7R4 turbofan engines installed on airplanes of 
U.S. registry. We also estimate that it would take about 0.5 work-hour 
per 1st stage fan blade to perform the proposed actions, and that the 
average labor rate is $80 per work-hour. Based on these figures, we 
estimate the total cost of the proposed AD to U.S. operators to be 
$21,240.

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.

[[Page 9278]]

    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 proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would not 
have a substantial direct effect on the States, on the relationship 
between the national Government and the States, or on the distribution 
of power and responsibilities among the various levels of government.
    For the reasons discussed above, I certify that the proposed AD:
    1. Is not a ``significant regulatory action'' under Executive Order 
12866;
    2. Is not a ``significant rule'' under the DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979); and
    3. Would not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD. 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, Safety.

The Proposed Amendment

    Under the authority delegated to me by the Administrator, the 
Federal Aviation Administration proposes to amend 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. The FAA amends Sec.  39.13 by removing Amendment 39-14430 (70 FR 
76381, December 27, 2005), and by adding a new airworthiness directive 
to read as follows:

Pratt & Whitney: Docket No. FAA-2005-23072; Directorate Identifier 
2005-NE-38-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by April 30, 
2007.

Affected ADs

    (b) This AD supersedes AD 2005-26-09.

Applicability

    (c) This AD applies to Pratt & Whitney (PW) JT9D-7R4 turbofan 
engines. These engines are installed on, but not limited to, Airbus 
A300 and A310, and Boeing 747 and 767 airplanes.

Unsafe Condition

    (d) This AD results from the discovery of inaccurate part 
quantity, part numbers, and serial numbers used in AD 2005-26-09. We 
are issuing this AD to prevent 1st stage fan blade fracture and 
uncontained engine failure, resulting in possible damage to the 
airplane.

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.
    (f) For 1st stage fan blades that are listed by part number (P/
N) and serial number (SN) in Table 1 of this AD, do the following:

                 Table 1.--Affected 1st Stage Fan Blades
------------------------------------------------------------------------
                    P/Ns                                  SNs
------------------------------------------------------------------------
5001341-022.................................  JW2804
5001341-022.................................  JW0354
5001341-022.................................  ND5746
5001341-022.................................  ND5770
5001341-022.................................  JW3992
5001341-022.................................  ND8615
5001341-022.................................  JW0442
5001341-022.................................  JW2317
5001341-022.................................  ND8631
5001341-022.................................  ND8635
5001341-022.................................  JW4624
5001341-022.................................  NE0394
5001341-022.................................  NE0153
5001341-022.................................  NN8054
5001341-022.................................  JW4693
5001341-022.................................  ND7304
5001341-022.................................  MG6108
5001341-022.................................  MG5862
5001341-022.................................  MG5619
5001341-022.................................  NE0308
5001341-022.................................  NE0200
5001341-022.................................  MG6797
5001341-022.................................  JW0230
5001341-022.................................  ND5652
5001341-022.................................  ND5775
5001341-022.................................  JW0251
5001341-022.................................  ND5719
5001341-022.................................  JW0248
5001341-022.................................  ND5785
5001341-022.................................  ND5676
5001341-022.................................  ND5661
5001341-022.................................  JW0265
5001341-022.................................  ND5699
5001341-022.................................  ND5767
5001341-022.................................  JW0259
5001341-022.................................  ND5680
5001341-022.................................  ND5749
5001341-022.................................  JW0235
5001341-022.................................  ND5776
5001341-022.................................  ND8580
5001341-022.................................  MG6039
5001341-022.................................  ND9127
5001341-022.................................  JW4287
5001341-022.................................  JW0262
5001341-022.................................  JW0445
5001341-022.................................  JW4665
5001341-022.................................  MG5901
5001341-022.................................  NE0303
5001341-022.................................  ND8703
5001341-022.................................  JW4574
5001341-022.................................  JW4286
5001341-022.................................  JW4491
5001341-022.................................  JW4630
5001341-022.................................  JW4391
5001341-022.................................  MG6550
5001341-022.................................  MG6776
5001341-022.................................  JW4586
5001341-022.................................  JW0352
5001341-022.................................  JW4261
5001341-022.................................  MG6135
5001341-022.................................  JW4685
5001341-022.................................  MG6772
5001341-022.................................  MG6793
5001341-022.................................  MG7111
5001341-022.................................  ND8618
5001341-022.................................  JW0644
5001341-022.................................  JW4631
5001341-022.................................  JW4651
5001341-022.................................  JW0234
5001341-022.................................  JW4646
804121......................................  NN9016
804121......................................  VJ3393
804121......................................  PX3694
804121......................................  RK9168
804121......................................  PX5023
804121......................................  VJ3324
804121......................................  VJ3504
804121......................................  NN9115
804121......................................  NN8936
804121......................................  PX3816
804121......................................  VJ3412
804121......................................  RK9163
804121......................................  VJ3447
804121......................................  RK9230
804121......................................  RK9109
804121......................................  PX4627
804121......................................  RK8990
804121......................................  SP9459
804121......................................  RK8656
804121......................................  NN8933
804121......................................  VJ3444
804121......................................  ND5864
804121......................................  NN9020
804121......................................  RK8905
804121......................................  SR1733
804121......................................  NN9047
804121......................................  PX3692
804121......................................  PX3786
804121......................................  NN9025
804121......................................  NN9007
804121......................................  RK9100
804121......................................  VJ3399
804121......................................  PX4970
804121......................................  PX5013

[[Page 9279]]

 
804121......................................  RK8904
804121......................................  NN8986
804121......................................  NN8829
804121......................................  VJ3459
804121......................................  RK9143
804121......................................  VJ3414
804121......................................  NN9028
804121......................................  SP1557
804121......................................  PX5003
804121......................................  PX5042
804121......................................  VJ3475
804121......................................  ND7330
804121......................................  PX3714
831021-003..................................  NS8913
831021-003..................................  ND6512
831021-003..................................  ND6941
831021-003..................................  ND9576
831021-003..................................  NS7555
831021-003..................................  NS8286
831021-003..................................  NS7447
831021-003..................................  ND6488
831021-003..................................  ND8296
831021-003..................................  ND6956
831021-003..................................  ND7879
831021-003..................................  ND6509
831021-003..................................  ND9814
831021-003..................................  NN7331
831021-003..................................  ND6991
831021-003..................................  ND6894
831021-003..................................  NS6413
831021-003..................................  ND7344
831021-003..................................  ND6947
831021-003..................................  NN8732
831021-003..................................  ND8536
831021-003..................................  ND6946
831021-003..................................  ND6723
831021-003..................................  ND9294
831021-003..................................  ND9290
831021-003..................................  ND6013
831021-003..................................  ND8937
831021-003..................................  NS7160
831021-003..................................  NS6435
831021-003..................................  NS6591
831021-003..................................  ND9558
831021-003..................................  NS8479
831021-003..................................  NS9382
831021-003..................................  ND8965
831021-003..................................  ND9837
831021-003..................................  ND5959
831021-003..................................  NS6491
831021-003..................................  NS9072
831021-003..................................  ND9625
831021-003..................................  ND6714
831021-003..................................  ND6820
831021-003..................................  ND8972
831021-003..................................  NE0286
831021-003..................................  NE0347
831021-003..................................  ND8010
831021-003..................................  ND8956
831021-003..................................  ND9535
831021-003..................................  ND9831
831021-003..................................  NE0227
831021-003..................................  ND8283
831021-003..................................  ND9730
831021-003..................................  NN7656
831021-003..................................  NS7775
831021-003..................................  ND9815
831021-003..................................  ND6135
831021-003..................................  NS8491
831021-003..................................  NS6395
831021-003..................................  NS8584
831021-003..................................  NN7272
831021-003..................................  MG7159
831021-003..................................  NS6592
831021-003..................................  ND7862
831021-003..................................  ND6684
831021-003..................................  NN7744
831021-003..................................  ND7480
831021-003..................................  ND7873
831021-003..................................  ND6827
831021-003..................................  ND6576
831021-003..................................  ND9261
831021-003..................................  NS8686
831021-003..................................  ND9052
831021-003..................................  ND6897
831021-003..................................  ND6565
831021-003..................................  NN8966
831021-003..................................  PX3707
831021-003..................................  NS7031
831021-003..................................  ND6584
831021-003..................................  ND9883
831021-003..................................  NS6535
831021-003..................................  ND7852
831021-003..................................  ND9662
831021-003..................................  ND7871
831021-003..................................  JW0106
831021-003..................................  ND8305
831021-003..................................  NS6409
831021-003..................................  NE0442
831021-003..................................  ND9095
831021-003..................................  ND9302
831021-003..................................  ND9023
831021-003..................................  ND8009
831021-003..................................  ND8477
831021-003..................................  ND7492
831021-003..................................  ND8776
831021-003..................................  ND6524
831021-003..................................  ND6704
831021-003..................................  ND8911
831021-003..................................  ND8789
831021-003..................................  ND8798
831021-003..................................  ND6407
831021-003..................................  ND7668
831021-003..................................  ND9179
831021-003..................................  NE0421
831021-003..................................  ND6513
831021-003..................................  ND6744
831021-003..................................  ND7654
831021-003..................................  ND7870
831021-003..................................  ND9759
831021-003..................................  ND6561
831021-003..................................  ND5826
831021-003..................................  ND6031
831021-003..................................  ND8714
831021-003..................................  ND8872
831021-003..................................  ND6678
831021-003..................................  ND6629
831021-003..................................  ND8995
831021-003..................................  NE0302
831021-003..................................  ND6405
831021-003..................................  NS8300
831021-003..................................  NS8769
831021-003..................................  NS7147
831021-003..................................  ND6649
831021-003..................................  ND7766
831021-003..................................  NS7864
831021-003..................................  NS8734
831021-003..................................  ND6677
831021-003..................................  NS7911
831021-003..................................  ND8205
831021-003..................................  ND8804
831021-003..................................  ND6639
831021-003..................................  ND8994
831021-003..................................  ND7275
831021-003..................................  ND9195
831021-003..................................  ND6178
831021-003..................................  ND8639
831021-003..................................  ND9760
831021-003..................................  ND9108X
831021-003..................................  ND6427
831021-003..................................  ND6590
831021-003..................................  NS6551
831021-003..................................  JW1158
831021-003..................................  ND6412
831021-003..................................  ND7922
831021-003..................................  NS8678
831021-003..................................  ND8930
831021-003..................................  ND6596
831021-003..................................  ND9570
831021-003..................................  NN9027
831021-003..................................  ND6446
831021-003..................................  NE0275
831021-003..................................  ND9917
831021-003..................................  NS7919
831021-003..................................  NS7907
831021-003..................................  ND6583
831021-003..................................  NN7420
831021-003..................................  ND7746
831021-003..................................  ND8187
831021-003..................................  NN8999
831021-003..................................  ND6043
831021-003..................................  ND7880
831021-003..................................  NN7175
831021-003..................................  ND9816
831021-003..................................  ND8174
831021-003..................................  ND6045
831021-003..................................  NS7562
831021-003..................................  JW0075
831021-003..................................  ND6848
831021-003..................................  ND8531
831021-003..................................  ND6311
831021-003..................................  ND8144
831021-003..................................  ND5798
831021-003..................................  ND8113
831021-003..................................  ND9642
831021-003..................................  ND7436
831021-003..................................  ND9054
831021-003..................................  ND9683
831021-003..................................  ND5991
831021-003..................................  ND6026
831021-003..................................  ND6616
831021-003..................................  ND6530
831021-003..................................  NE0374
831021-003..................................  ND6364
831021-003..................................  ND7718
831021-003..................................  ND6473
831021-003..................................  ND6436
831021-003..................................  ND6887
831021-003..................................  ND6518
831021-003..................................  ND6479
831021-003..................................  NS6330
831021-003..................................  ND7264
831021-003..................................  ND8151
831021-003..................................  ND6562
831021-003..................................  NS8776
831021-003..................................  ND6519
831021-003..................................  ND7659
831021-003..................................  NS9049
831021-003..................................  NS6861
831021-003..................................  ND9571
831021-003..................................  ND9346
831021-003..................................  ND6501
831021-003..................................  NS8505

[[Page 9280]]

 
831021-003..................................  ND9338
831021-003..................................  ND9775
831021-003..................................  ND6485
831021-003..................................  ND7165
831021-003..................................  ND9371
831021-003..................................  ND9537
831021-003..................................  NS7889
831021-003..................................  ND7877
831021-003..................................  ND8670
831021-003..................................  ND9032
831021-003..................................  ND8781
831021-003..................................  ND8604
831021-003..................................  ND9329
831021-003..................................  ND9110
831021-003..................................  ND5997
831021-003..................................  ND6027
831021-003..................................  ND9589
831021-003..................................  ND6575
831021-003..................................  ND6592
831021-003..................................  ND6463
831021-003..................................  NS8583
831021-003..................................  NS8590
831021-003..................................  NS8567
831021-003..................................  NS6795
831021-003..................................  NS7110
831021-003..................................  NS6587
831021-003..................................  NS6404
831021-003..................................  ND6486
5001341-022.................................  JW0942
5001341-022.................................  ND9231
5001341-022.................................  JW4812
5001341-022.................................  ND6555
5001341-022.................................  M1375
5001341-022.................................  MG6627
5001341-022.................................  MG6794
5001341-022.................................  ND9399
5001341-022.................................  NE0084
5001341-022.................................  MG6252
5001341-022.................................  ND7422
5001341-022.................................  ND7043
5001341-022.................................  MG5722
5001341-022.................................  MG5918
5001341-022.................................  ND6984
5001341-022.................................  M0839
5001341-022.................................  M0922
5001341-022.................................  M0938
5001341-022.................................  M1117
5001341-022.................................  M0307
5001341-022.................................  JW3871
5001341-022.................................  M1125
5001341-022.................................  M1149
5001341-022.................................  JW2681
5001341-022.................................  M0270
5001341-022.................................  M1120
5001341-022.................................  M0205
5001341-022.................................  AE9352
5001341-022.................................  JW3492
5001341-022.................................  ND6148
5001341-022.................................  ND8907
5001341-022.................................  M1235
5001341-022.................................  MG5585
5001341-022.................................  ND8436
5001341-022.................................  MG5696
5001341-022.................................  ND8704
5001341-022.................................  JW2284
5001341-022.................................  JW2313
5001341-022.................................  JW2498
5001341-022.................................  JW2541
5001341-022.................................  JW2560
5001341-022.................................  JW2589
5001341-022.................................  JW2639
5001341-022.................................  JW2760
5001341-022.................................  JW2792
5001341-022.................................  M0579
5001341-022.................................  MG2825
5001341-022.................................  MG5477
5001341-022.................................  ND5917
5001341-022.................................  JW1976
5001341-022.................................  JW2653
5001341-022.................................  JW2608
5001341-022.................................  JW2727
5001341-022.................................  JW2764
5001341-022.................................  JW2265
5001341-022.................................  JW2474
5001341-022.................................  JW2396
5001341-022.................................  JW3554
5001341-022.................................  JW2667
5001341-022.................................  MG2302
5001341-022.................................  MG3972
5001341-022.................................  JW3930
5001341-022.................................  ND6749
5001341-022.................................  M1172
5001341-022.................................  JW2104
5001341-022.................................  JW2519
5001341-022.................................  JW2640
5001341-022.................................  JW2517
5001341-022.................................  JW2663
5001341-022.................................  JW2823
5001341-022.................................  M0536
5001341-022.................................  JW2725
5001341-022.................................  MG5917
5001341-022.................................  JW0681
5001341-022.................................  JW0711
5001341-022.................................  JW0740
5001341-022.................................  JW0807
5001341-022.................................  JW1089
5001341-022.................................  JW1362
5001341-022.................................  JW2065
5001341-022.................................  MG2434
5001341-022.................................  MG2846
5001341-022.................................  JW0806
804121......................................  NN9854
804121......................................  NN9024
804121......................................  NN9032
804121......................................  PX5029
804121......................................  NN9050
804121......................................  NS8242
804121......................................  NS8260
804121......................................  PX4273
804121......................................  PX4378
804121......................................  RL0857
804121......................................  RX8763
804121......................................  NS8331
804121......................................  NN9824
804121......................................  MG6979
804121......................................  MG7023
804121......................................  MG7055
804121......................................  RK8914
804121......................................  RL0023
804121......................................  PX4328
804121......................................  RK9008
804121......................................  TG1506
804121......................................  KK8226
804121......................................  MG2604
804121......................................  NS6691
804121......................................  RK8968
804121......................................  NN9917
804121......................................  RK7824
804121......................................  M1343
804121......................................  NS6559
804121......................................  NS7767
804121......................................  NE0363
804121......................................  PX3771
804121......................................  NN9972
804121......................................  RL0460
804121......................................  RK8310
804121......................................  SR2115
804121......................................  TG2826
804121......................................  PX5018
804121......................................  PX5002
831021-003..................................  ND7627
831021-003..................................  ND6890
831021-003..................................  ND7461
831021-003..................................  ND9616
831021-003..................................  NE0413
831021-003..................................  NS8825
831021-003..................................  NS6350
831021-003..................................  NS7168
831021-003..................................  NS7705
831021-003..................................  NS7848
831021-003..................................  ND9128
831021-003..................................  ND9541
831021-003..................................  ND9671
831021-003..................................  ND9684
831021-003..................................  NE0277
831021-003..................................  NE0384
831021-003..................................  NE0396
831021-003..................................  ND6421
831021-003..................................  ND6599
831021-003..................................  ND6614
831021-003..................................  ND7847
831021-003..................................  ND8346
831021-003..................................  ND8853
831021-003..................................  ND8915
831021-003..................................  NS8719
831021-003..................................  NS8838
831021-003..................................  NT0169
831021-003..................................  NS9584
831021-003..................................  ND6445
831021-003..................................  ND6834
831021-003..................................  ND7467
831021-003..................................  ND8887
831021-003..................................  ND6520
831021-003..................................  NS8611
831021-003..................................  NS7640
831021-003..................................  NN7037
831021-003..................................  NN7590
831021-003..................................  NN8120
831021-003..................................  NN8573
831021-003..................................  NN9719
831021-003..................................  NS8784
831021-003..................................  TB6B367
831021-003..................................  NN9557
831021-003..................................  NN9710
831021-003..................................  NS8374
831021-003..................................  NS8770
831021-003..................................  NS9022
831021-003..................................  NS8416
831021-003..................................  NS6474
831021-003..................................  ND8912
831021-003..................................  NT0108
831021-003..................................  NS8836
831021-003..................................  NN8310
831021-003..................................  NS8559
5001341-022.................................  JW4713
5001341-022.................................  MG6743
5001341-022.................................  ND6924
831021-003..................................  ND9177
831021-003..................................  ND9496
831021-003..................................  NS7894
831021-003..................................  NS8559
831021-003..................................  NS9072
804121......................................  PX3805

[[Page 9281]]

 
804121......................................  PX4266
------------------------------------------------------------------------

For Engines Installed on an Airplane

    (1) For engines installed on an airplane with affected 1st stage 
fan blades installed, perform the actions in paragraphs (f)(3) 
through (f)(6)(ii) of this AD at the next 1st stage fan blade 
exposure.

For Engines Not Installed on an Airplane, or, for Affected 1st Stage 
Fan Blades Not Installed in an Engine

    (2) For engines not installed on an airplane with affected 1st 
stage fan blades installed, or, for affected 1st stage fan blades 
not installed in an engine, paragraph (h) of this AD applies.

1st Stage Fan Blade Check

    (3) Check the 1st stage fan blade for a circled, letter I, on 
the approved marking area of the outboard side of the blade 
platform. If the blade has this marking, no further action is 
required.
    (4) Remove 1st stage fan blades without a circled, letter I, on 
the approved marking area of the outboard side of the blade 
platform, if installed.
    (5) Inspect the 1st stage fan blade root thickness. You can find 
information on inspecting the blade root thickness in PW Engine 
Manual Section 72-31-02, Inspect-01, and Repair-23.
    (6) For 1st stage fan blades that pass the inspection referenced 
in paragraph (f)(5) of this AD:
    (i) Vibropeen the letter I and a circle around that letter, on 
the approved marking area of the outboard side of the blade 
platform. You can find information on approved blade marking in the 
JT9D-7R4 Engine Manual, Section 72-31-02, Typical Repair-13, Mark 
Repair Codes.
    (ii) Return the 1st stage fan blades to service.

Definition

    (g) For the purposes of paragraph (f)(1) of this AD, next 1st 
stage fan blade exposure is:
    (1) When any 1st stage fan blade is removed from the engine; or
    (2) When the 1st stage fan hub is removed from the engine.

Prohibited Installation

    (h) After the effective date of this AD, do not install any 1st 
stage fan blades listed in Table 1 of this AD on any airplane, 
unless the actions of this AD have been done to the 1st stage fan 
blades.

Alternative Methods of Compliance

    (i) The Manager, Engine Certification Office, has the authority 
to approve alternative methods of compliance for this AD if 
requested using the procedures found in 14 CFR 39.19.

Related Information

    (j) None.

    Issued in Burlington, Massachusetts, on February 23, 2007.
Peter A. White,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
 [FR Doc. E7-3561 Filed 2-28-07; 8:45 am]
BILLING CODE 4910-13-P