[Federal Register Volume 72, Number 169 (Friday, August 31, 2007)]
[Rules and Regulations]
[Pages 50204-50208]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-17210]


=======================================================================
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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-23072; Directorate Identifier 2005-NE-38-AD; 
Amendment 39-15186; AD 2007-18-06]
RIN 2120-AA64


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

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

ACTION: Final rule.

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

[[Page 50205]]

SUMMARY: The FAA is superseding 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 AD requires the same actions but corrects 12 P/Ns, adds 10 
part SNs, and adds the definition of next fan blade exposure to the 
compliance section. 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.

DATES: This AD becomes effective October 5, 2007.

ADDRESSES: The Docket Operations office is located at U.S. Department 
of Transportation, Docket Operations, M-30, West Building Ground Floor, 
Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: 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: The FAA proposed to amend 14 CFR part 39 by 
superseding AD 2005-26-09, Amendment 39-14430 (70 FR 76381, December 
27, 2005), with a proposed AD. The proposed AD applies to (PW) JT9D-7R4 
turbofan engines. We published the proposed AD in the Federal Register 
on March 1, 2007 (72 FR 9276). That action proposed to require 
inspection of the blade root thickness of 1st stage fan blades 
identified by P/N and SN.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://dms.dot.gov; or in person at the Docket Operations office between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD 
docket contains this AD, the regulatory evaluation, any comments 
received, and other information. The street address for the Docket 
Operations office (telephone (800) 647-5527) is provided in the 
ADDRESSES section. Comments will be available in the AD docket shortly 
after receipt.

Comments

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

Duplicate Serial Number

    One commenter asks us to remove a duplicate serial number from 
Table 1. The commenter states that we listed two fan blades, P/N 
831021, serial number NS8559 in Table 1. We agree. We deleted one of 
the duplicate SNs.

Corrections to the NPRM

    We found one typographical error in a blade SN. We changed ND6924 
to ND8924. Blade SN ND6924 is not included in the population of suspect 
blades. We also found the population is not 531, it is 538. We 
corrected these errors in the NPRM.

Conclusion

    We have carefully reviewed the available data, including the 
comments received, and determined that air safety and the public 
interest require adopting the AD with the changes described previously. 
We have determined that these changes will cause only a minimal 
increase to the economic burden on any operator and will not increase 
the scope of the AD.

Costs of Compliance

    We estimate that this AD will affect 538 1st stage fan blades 
installed on JT9D-7R4 turbofan engines installed on airplanes of U.S. 
registry. We also estimate that it will 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 this AD to U.S. operators to be $21,520.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this AD will not have federalism 
implications under Executive Order 13132. This AD will not have a 
substantial direct effect on the States, on the relationship between 
the national government and the States, or on the distribution of power 
and responsibilities among the various levels of government.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866;
    (2) Is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and
    (3) Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.
    We prepared a summary of the costs to comply with this AD and 
placed it in the AD Docket. You may get a copy of this summary at the 
address listed under ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the Federal Aviation Administration amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by removing Amendment 39-14430 70 FR 
76381, December 27, 2005, and by adding a new airworthiness directive, 
Amendment 39-15196, to read as follows:

2007-18-06 Pratt & Whitney: Amendment 39-15196. Docket No. FAA-2005-
23072; Directorate Identifier 2005-NE-38-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective October 
5, 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.

[[Page 50206]]

Unsafe Condition

    (d) This AD results from the discovery of inaccurate part 
quantity, part numbers (P/Ns), and serial numbers (SNs) 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 P/N and 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
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

[[Page 50207]]

 
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
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

[[Page 50208]]

 
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................................  JW2313
5001341-022................................  JW2498
5001341-022................................  JW2541
5001341-022................................  JW2560
5001341-022................................  JW2589
5001341-022................................  JW2639
5001341-022................................  JW2760
5001341-022................................  JW2792
5001341-022................................  JW4713
5001341-022................................  MG6743
5001341-022................................  ND8924
831021-003.................................  ND9177
831021-003.................................  ND9496
831021-003.................................  NS7894
831021-003.................................  NS9072
804121.....................................  PX3805
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 August 24, 2007.
Mark A. Rumizen,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. E7-17210 Filed 8-30-07; 8:45 am]
BILLING CODE 4910-13-P