[Federal Register Volume 66, Number 144 (Thursday, July 26, 2001)]
[Rules and Regulations]
[Pages 38896-38902]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-18432]


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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NE-47-AD; Amendment 39-12346; AD 2001-15-12]
RIN 2120-AA64


Airworthiness Directives; Pratt and Whitney PW4000 Series 
Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule, request for comments.

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

SUMMARY: This amendment supersedes two airworthiness directives (AD's), 
2000-22-01 and 2001-09-07, that both apply to Pratt and Whitney (PW) 
model PW4000 series turbofan engines. AD 2000-22-01 requires that 
operators limit the number of PW4000 engines equipped with the high 
pressure compressors (HPC) in the cutback stator (CBS) configuration to 
no more than one engine on each airplane, and prohibits the 
installation of engines with HPC modules in the CBS configuration after 
the effective date of that AD. AD 2001-09-07 requires that operators 
limit the number of engines with potentially reduced stability to no 
more than one engine on each airplane, and remove those engines before 
exceeding certain cyclic limits. Reports of HPC surges in PW4000 
engines that have the HPC in the CBS configuration prompted those AD's.
    This Amendment will limit the number of PW4000 engines with 
potentially reduced stability on each airplane by applying rules based 
on airplane and engine configuration, and require that engines that 
exceed HPC compressor cyclic limits based on cycles-since-overhaul 
(CSO) are removed from service. This AD will also limit the number of 
engines with HPC CBS configuration to one on each airplane, and will 
establish a minimum rebuild standard for engines that are returned to 
service. This Amendment is prompted by further analyses of compressor 
surges in PW4000 engines. The actions specified by this AD are intended 
to prevent multiple-engine power losses due to high pressure compressor 
(HPC) surge and to reduce the rate of single-engine surge events.

DATES: Effective August 10, 2001.
    Comments for inclusion in the Rules Docket must be received on or 
before September 24, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 2000-NE-47-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may also be sent 
via the Internet using the following address: ``[email protected].'' Comments sent via the Internet must contain the 
docket number in the subject line.

FOR FURTHER INFORMATION CONTACT: Peter White, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
238-7128; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: The FAA has noted a growing number of take-
off (T/O) surge events in Pratt and Whitney PW4000 Series turbofan 
engines. These surges typically occur within 60 seconds after throttle 
advance to T/O power, a critical phase of flight. These events have 
resulted in numerous aborted T/O's, in-flight engine shutdowns, and 
diverted flights. A surge of this kind on a single engine of a multi-
engine airplane would not normally result in an unsafe condition. To 
date, two dual-engine surge events have occurred, the latest in March 
2001 involving a twin-engine aircraft.
    The investigation into these events has revealed no special causes 
for these surges. The FAA believes that a low-stall margin results from 
open clearances in the aft stages of the HPC. The worst-case open 
clearance

[[Page 38897]]

condition in the aft stage compressor of the HPC occurs about 60 
seconds after the throttle is advanced for T/O. A binding of the 
compressor flowpath and stator segments within the outer case (causing 
out-of-round flowpath or local open clearances) adds to this normally 
worst-case condition. Pratt and Whitney has initiated a root-cause 
analysis program to verify this belief, and to identify other 
contributing factors that may contribute to the high rate of takeoff 
surges in the PW4000 fleet.
    On October 25, 2000, the FAA issued AD 2000-22-01 (65 FR 63793, 
dated October 25, 2000), applicable to PW4000 series engines, to 
require limiting the number of engines with the HPC CBS configuration, 
which are used on Boeing 747, Boeing 767, and McDonnell Douglas MD-11 
series airplanes, to one on each airplane according to the cyclic 
limits specified in that AD. AD 2000-22-01 also prohibits using engines 
with HPC modules that incorporated the HPC CBS configuration, after the 
effective date of that AD.
    On April 20, 2001, the FAA issued AD 2001-09-07 (66 FR 21083, dated 
April 27, 2001), applicable to PW4000 series turbofan engines, to 
require limiting the number of PW4000 engines to no more than one 
engine with potentially reduced stability on each airplane and removal 
of certain PW4000 engines before exceeding cyclic limits that are 
determined by airplane model. Those engines with potentially reduced 
stability are listed by serial number in the AD. AD 2001-09-07 
superseded emergency AD 2001-08-52. AD 2001-09-07 also requires the 
removal of certain PW4000 engines that have an HPC with 1,500 or more 
CSO greater than the high pressure turbine (HPT) CSO, and establishes a 
minimum rebuild standard for engines that are returned to service.
    Since AD 2000-22-01 and AD 2001-09-07 were issued, the FAA has 
reevaluated those requirements and found that the requirements of those 
AD's were not sufficient to meet the original safety intent of those 
AD's. The PW4000 fleet was evaluated by configuration, installation, 
thrust rating and other variables to determine which subpopulations are 
most prone to high power takeoff surges. This information was then 
evaluated to create cyclic limits for each airplane and engine 
combination to maintain the risk of a multiple-engine dual surge risk 
at an acceptable level. Cyclic limits were then developed for the HPC 
to reduce the single engine surge rate.

FAA's Determination of an Unsafe Condition and Proposed Actions

    Since the unsafe condition described is likely to exist or develop 
on other PW4000 series turbofan engines of the same type design, this 
AD is being issued to prevent multiple-engine power losses due to HPC 
surge and to reduce the rate of single-engine surge events. This AD 
requires:
     Limiting the number of engines with the HPC CBS 
configuration to one on each airplane within 100 cycles-in-service 
(CIS) after the effective date of this AD, AND
     Limiting the number of PW4000 engines with potentially 
reduced stability on each airplane, based upon airplane and engine 
configuration, within 50 CIS after the effective date of this AD, AND
     Removing certain PW4000 engines from service, before 
exceeding cyclic limits on the HPC based on CSO, within 50 CIS after 
the effective date of this AD, AND
     Preventing the build-up of PW4000 engines that have an HPC 
with 1,500 or more CSO greater than the HPT CSO, AND
     A minimum rebuild standard for engines that are returned 
to service.

Interim Action

    The actions specified in this AD are considered interim action and 
further action is anticipated based on the continuing investigation of 
the HPC surges. This AD has been coordinated with the FAA Transport 
Aircraft Directorate.

Immediate Adoption of This AD

    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this rule by 
submitting such written data, views, or arguments as they may desire. 
Communications should identify the Rules Docket number and be submitted 
in triplicate to the address specified under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the rule. All comments submitted will be 
available, both before and after the closing date for comments, in the 
Rules Docket for examination by interested persons. A report that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2000-NE-47-AD.'' The postcard will be date stamped and 
returned to the commenter.

Regulatory Impact

    This final rule does not have federalism implications, as defined 
in Executive Order 13132, because it 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. Accordingly, 
the FAA has not consulted with state authorities prior to publication 
of this final rule.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and is not a ``significant regulatory action'' 
under Executive Order 12866. It has been determined further that this 
action involves an emergency regulation under DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979). If it is determined 
that this emergency regulation otherwise would be significant under DOT 
Regulatory Policies and Procedures, a final regulatory evaluation will 
be prepared and placed in the Rules Docket. A copy of it, if filed, 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, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the

[[Page 38898]]

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 removing Amendment 39-11947 (65 FR 
63793, dated October 25, 2000) and Amendment 39-12212 (66 FR 21083, 
dated April 27, 2001), and by adding a new airworthiness directive 
(AD), Amendment 39-12346, to read as follows:

2001-15-12  Pratt and Whitney: Amendment 39-12346. Docket No. 2000-
NE-47-AD. Supersedes Amendment 39-11947, and Amendment 39-12212.

    Applicability: This airworthiness directive (AD) is applicable 
to Pratt and Whitney (PW) model PW4050, PW4052, PW4056, PW4060, 
PW4060A, PW4060C, PW4062, PW4152, PW4156, PW4156A, PW4158, PW4160, 
PW4460, PW4462, and PW4650 turbofan engines. These engines are 
installed on, but not limited to, certain models of Airbus Industrie 
A300, Airbus Industrie A310, Boeing 747, Boeing 767, and McDonnell 
Douglas MD-11 series airplanes.

    Note 1: This AD applies to each engine identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For engines that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (l) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Compliance with this AD is required as indicated, 
unless already done.
    To prevent multiple-engine power losses due to high pressure 
compressor (HPC) surge and to reduce the rate of single-engine surge 
events, do the following:
    (a) When complying with this AD, use the following Table 1 of 
this AD to determine the configuration of each engine on each 
airplane:

                                     Table 1.--Engine Configuration Listing
----------------------------------------------------------------------------------------------------------------
              Configuration                      Configuration designator                  Description
----------------------------------------------------------------------------------------------------------------
(1) Phase 1 without high pressure turbine  A                                    Engines that did not incorporate
 (HPT) 1st turbine vane cut back (1TVCB).                                        the Phase 3 configuration at
                                                                                 the time they were originally
                                                                                 manufactured, or have not been
                                                                                 converted to Phase 3
                                                                                 configuration; and have not
                                                                                 incorporated HPT 1TVCB using
                                                                                 any revision of SB PW4ENG 72-
                                                                                 514.
----------------------------------------------------------------------------------------------------------------
(2) Phase 1 with 1TVCB.                    B                                    Same as configuration (1) except
                                                                                 that HPT 1TVCB has been
                                                                                 incorporated using any revision
                                                                                 of SB PW4ENG 72-514.
----------------------------------------------------------------------------------------------------------------
(3) Phase 3, 2nd Run.                      B                                    Engines that incorporated the
                                                                                 Phase 3 configuration at the
                                                                                 time they were originally
                                                                                 manufactured, or have been
                                                                                 converted to the Phase 3
                                                                                 configuration during service;
                                                                                 and that have had at least one
                                                                                 HPC overhaul since new.
----------------------------------------------------------------------------------------------------------------
(4) Phase 3, 1st Run.                      C                                    Same as configuration (3) except
                                                                                 that that the engine has not
                                                                                 had an HPC overhaul since new.
----------------------------------------------------------------------------------------------------------------
(5) HPC Cutback Stator Configuration       D                                    Engines that incorporated any
 Engines.                                                                        revision of SB's PW4ENG72-706,
                                                                                 PW4ENG72-704, or PW4ENG72-711.
----------------------------------------------------------------------------------------------------------------

    (b) Within 50 cycles-in-service (CIS) after the effective date 
of this AD, and thereafter, remove engines from service that exceed 
the HPC cycles-since-new (CSN) or cycles-since-overhaul (CSO) limits 
in the following Table 2 of this AD:

                               Table 2.--HPC Cyclic Limits by Engine Configuration
----------------------------------------------------------------------------------------------------------------
                                                                           Engine configuration  (CSO or CSN)
          Engine model                 Engine serial number (SN)      ------------------------------------------
                                                                           A          B          C          D
----------------------------------------------------------------------------------------------------------------
(1) PW4152                       All                                   3,600      5,600      8,000      1,300
----------------------------------------------------------------------------------------------------------------

[[Page 38899]]

 
(2) PW4156, PW4156A, and         717205, 717702, 717703, 717710,       3,200      4,400      8,000      1,300
 PW4158.                          717752, 717788, 717798, 717799,
                                  724023, 724026, 724027, 724033,
                                  724034, 724036, 724037, 724040,
                                  724041, 724044, 724045, 724048,
                                  724049, 724050, 724052, 724055,
                                  724056, 724059, 724061, 724062,
                                  724063, 724065, 724067, 724073,
                                  724074, 724075, 724079, 724094,
                                  724095, 724551, 724552, 724555,
                                  724556, 724557, 724558, 724561,
                                  724562, 724563, 724564, 724567,
                                  724568, 724569, 724570, 724571,
                                  724572, 724573, 724574, 724575,
                                  724576, 724578, 724640, 724806,
                                  724807, 724808, 724809, 724811,
                                  724820, 724821, 724827, 724833,
                                  724835, 724836, 724840, 724841,
                                  724848, 724849, 724855, 724857,
                                  724858, 724861, 724862, 724865,
                                  724866, 724868, 724909, 724910,
                                  724913, 724914, 724924, 724925,
                                  724926, 724927, 727912, 728519,
                                  728520, 728521, 728522, 728523,
                                  728524, 728525, 728526, 728527,
                                  728528, 728534, 728535, 728536,
                                  728537, 728538, 728539, 728540,
                                  728541, 728542, 728543, 728544,
                                  728545, 728546, 728547, 728548,
                                  728549, 728550, 728551, 728552,
                                  728553, 728554, 728557, 728558,
                                  728559, 728560, 728561, 728562,
                                  728563, 728564
----------------------------------------------------------------------------------------------------------------
(3) PW4158.                      717704, 724001, 724002, 724004,       6,500      7,500      8,000      1,300
                                  724005, 724006, 724007, 724008,
                                  724009, 724010, 724011, 724019,
                                  724020, 724031, 724035, 724038,
                                  724039, 724042, 724043, 724047,
                                  724068, 724069, 724071, 724076,
                                  724077, 724080, 724085, 724086,
                                  724087, 724092, 724093, 724096,
                                  724097, 724801, 724802, 724803,
                                  724804, 724805, 724813, 724814,
                                  724819, 724823, 724824, 724825,
                                  724826, 724828, 724831, 724832,
                                  724843, 724846, 724847, 724851,
                                  724852, 724853, 724854, 724859,
                                  724860, 724863, 724864, 724867,
                                  724869, 724870, 724871, 724872,
                                  724873, 724874, 724875, 724876,
                                  724880, 724881, 724882, 724883,
                                  724884, 724885, 724886, 724887,
                                  724888, 724889, 724890, 724892,
                                  724893, 724894, 724895, 724896,
                                  724897, 724898, 724899, 724900,
                                  724932, 727315, 727436, 728501,
                                  728502, 728503, 728504, 728505,
                                  728506, 728507, 728508, 728509,
                                  728510, 728511, 728515, 728518,
                                  728531, 728532, 728533
----------------------------------------------------------------------------------------------------------------
(4) PW4156, PW4156A, and         All others not listed by SN in this   2,150      2,800      8,000      1,300
 PW4158.                          Table.
----------------------------------------------------------------------------------------------------------------
(5) PW4052 and 4056.             All engines.                          3,000      4,400      4,400      1,300
----------------------------------------------------------------------------------------------------------------
(6) PW4060, PW4060C, PW4062,     All engines.                          2,150      3,600      4,400      1,300
 PW4460, and PW4462.
----------------------------------------------------------------------------------------------------------------

Engines Installed on Boeing 747 Airplanes

    (c) Within 50 CIS after the effective date of this AD, and 
thereafter, for engines installed on Boeing 747 series aircraft, 
configure the airplane so that all of the following rules are met:
    (1) At least one engine must be below the cyclic limits listed 
under Rule 1a in the following Table 3 of this AD:

                                                                                             Table 3.--HPC CSO or CSN Cyclic Limits by Engine Configuration for Boeing 747 Airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
     Number of engines in each Configuration on the Airplane                              Rule 1a                                             Rule 1b                                            Rule 1c                             Rule 1d  (Quantity of engines in each
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------                   configuration)
                                                                                                                                                                                                                              --------------------------------------------------
              A                     B or C               D                 A              B or C               D                A              B or C             D                A              B or C             D                A              B or C             D
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(i) 4                          0                 0                 700               ................  ................  1300             ...............  ...............  1800             ...............  ...............  (1)--2400        ...............  ...............
                                                                                                                                                                                                                               (3)--400.......
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(ii) 3                         1                 0                 700               2300              ................  1300             2600             ...............  1800             3000             ...............  (1)--2400        (1)--1800        ...............
                                                                                                                                                                                                                               (2)--400.......
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 38900]]

 
(iii) 2                        2                 0                 700               2300              ................  1300             2600             ...............  1800             3000             ...............  (1)--2400        (2)--1800        ...............
                                                                                                                                                                                                                               (1)--400.......
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(iv) 1                         3                 0                 700               2300              ................  1300             2600             ...............  1800             3000             ...............  (1)--2400        (3)--1800        ...............
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(v) 0                          4                 0                 ................  2300              ................  ...............  2600             ...............  ...............  3000             ...............  ...............  (1)--3300        ...............
                                                                                                                                                                                                                                                (3)--1800......
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(vi) 3                         0                 1                 700               ................  750               1300             ...............  750              1800             ...............  750              (1)--2400        ...............  (1)--750.
                                                                                                                                                                                                                               (2)--400.......
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(vii) 2                        1                 1                 700               2300              750               1300             2600             750              1800             3000             750              (1)--2400        (1)--1800        (1)--750.
                                                                                                                                                                                                                               (1)--400.......
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(viii) 1                       2                 1                 700               2300              750               1300             2600             750              1800             3000             750              (1)--2400        (2)--1800        (1)--750.
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(ix) 0                         3                 1                 ................  2300              750               ...............  2600             750              ...............  3000             750              ...............  (1)--3300        (1)--750.
                                                                                                                                                                                                                                                (2)--1800......
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

    (2) At least two engines must be below the cyclic limits listed 
under Rule 1b in Table 3 of this AD.
    (3) At least three engines must be below the cyclic limits 
listed under Rule 1c in Table 3 of this AD.
    (4) At least one engine must be below the cyclic limits listed 
under Rule 1d in Table 3 of this AD. When applying Rule 1d of this 
AD, and two limits are shown for an engine configuration, the higher 
cyclic limit for that configuration must be applied only to the 
engine with the highest CSO or CSN of that configuration. The lower 
limit is then applied to the remaining engines of that 
configuration.

Engines Installed on McDonnell Douglas MD-11 Airplanes

    (d) Within 50 CIS after the effective date of this AD, and 
thereafter, for engines installed on McDonnell Douglas MD-11 
airplanes, configure the airplane so that all of the following rules 
are met:
    (1) At least one engine must be below the cyclic limits listed 
under Rule 2a in the following Table 4 of this AD:

                                                                                                               Table 4.--HPC CSO or CSN Cyclic Limits by Engine Configuration for McDonnell Douglas MD-11
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                 Number of engines in each  Configuration the Airplane                                                     Rule 2a                                                                     Rule 2b                                             Rule 2c  (Quantity of Engines in each Configuration)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
               A                        B                  C                  D                  A                  B                  C                  D                  A                  B                  C                  D                  A                  B                 C                 D
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 (i) 3                          0                  0                  0                  850                .................  .................  .................  1000               .................  .................  .................  (1)--1600          ................  ................  ................
                                                                                                                                                                                                                                                 (2)--600.........
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(ii) 2                          1                  0                  0                  850                1700               .................  .................  1000               2300               .................  .................  (1)--1600          (1)--1400         ................  ................
                                                                                                                                                                                                                                                 (1)--600.........
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(iii) 1                         2                  0                  0                  850                1700               .................  .................  1000               2300               .................  .................  (1)--1600          (2)--1400         ................  ................
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(iv) 0                          3                  0                  0                  .................  1700               .................  .................  .................  2300               .................  .................  .................  (1)--3000         ................  ................
                                                                                                                                                                                                                                                                    (2)--1400.......
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(v) 2                           0                  1                  0                  850                .................  2650               .................  1000               .................  2900               .................  (1)--1600          ................  (1)--2800         ................
                                                                                                                                                                                                                                                 (1)--600.........
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(vi) 1                          0                  2                  0                  850                .................  2650               .................  1000               .................  2900               .................  (1)--1600          ................  (2)--2800         ................
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(vii) 0                         0                  3                  0                  .................  .................  2650               .................  .................  .................  2900               .................  .................  ................  (1)--3200         ................
                                                                                                                                                                                                                                                                                      (2)--2800.......
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(viii) 2                        0                  0                  1                  850                .................  .................  750                1000               .................  .................  750                (1)--1600          ................  ................  (1)--750.
                                                                                                                                                                                                                                                 (1)--600.........
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(ix) 0                          2                  1                  0                  .................  1700               2650               .................  .................  2300               2900               .................  .................  (1)--3000         (1)--2800         ................
                                                                                                                                                                                                                                                                    (1)--1400.......
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(x) 0                           1                  2                  0                  .................  1700               2650               .................  .................  2300               2900               .................  .................  (1)--3000         (2)--2800         ................
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(xi) 0                          2                  0                  1                  .................  1700               .................  750                .................  2300               .................  750                .................  (1)--3000         ................  (1)--750.
                                                                                                                                                                                                                                                                    (1)--1400.......
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(xii) 0                         0                  2                  1                  .................  .................  2650               750                .................  .................  2900               750                .................  ................  (1)--3200         (1)--750.
                                                                                                                                                                                                                                                                                      (1)--2800.......
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(xiii) 1                        1                  1                  0                  850                1700               2650               .................  1000               2300               2900               .................  (1)--1600          (1)--1400         (1)--2800         ................
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(xiv) 1                         1                  0                  1                  850                1700               .................  750                1000               2300               .................  750                (1)--1600          (1)--1400         ................  (1)--750.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 38901]]

 
(xv) 1                          0                  1                  1                  850                .................  2650               750                1000               .................  2900               750                (1)--1600          ................  (1)--2800         (1)--750.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(xvi) 0                         1                  1                  1                  .................  1700               2650               750                .................  2300               2900               750                .................  (1)--3000         (1)--2800         (1)--750.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

    (2) At least two engines must be below the cyclic limits listed 
under Rule 2b in Table 4 of this AD.
    (3) At least one engine must be below the cyclic limits listed 
under Rule 2c in Table 4 of this AD. When applying Rule 2c of this 
AD, and two limits are shown for an engine configuration, the higher 
cyclic limit for that configuration must be applied only to the 
engine with the highest CSO or CSN of that configuration. The lower 
limit is then applied to the remaining engines of that 
configuration.

Engines Installed on Boeing 767, Airbus A300, or Airbus A310 Airplanes

    (e) Within 50 CIS after the effective date of this AD, and 
thereafter, for engines installed on Boeing 767 Series, Airbus A300 
series or Airbus A310 series airplanes, configure the airplane so 
that no more than one engine may exceed the cyclic limits listed in 
the following Table 5 of this AD:

             Table 5.--HPC CSO or CSN Cyclic Limits by Engine Configuration for Twin-Engine Airplane
----------------------------------------------------------------------------------------------------------------
                                                                           Engine configuration  (CSO or CSN)
          Engine model                 Engine serial number (SN)      ------------------------------------------
                                                                           A          B          C          D
----------------------------------------------------------------------------------------------------------------
(1) PW4152.                      All                                   2,500      4,000      6,600      750
----------------------------------------------------------------------------------------------------------------
(2) PW4156, PW4156A, and         717205, 717702, 717703, 717710,       2,000      3,200      6,600      750
 PW4158.                          717752, 717788, 717798, 717799,
                                  724023, 724026, 724027, 724033,
                                  724034, 724036, 724037, 724040,
                                  724041, 724044, 724045, 724048,
                                  724049, 724050, 724052, 724055,
                                  724056, 724059, 724061, 724062,
                                  724063, 724065, 724067, 724073,
                                  724074, 724075, 724079, 724094,
                                  724095, 724551, 724552, 724555,
                                  724556, 724557, 724558, 724561,
                                  724562, 724563, 724564, 724567,
                                  724568, 724569, 724570, 724571,
                                  724572, 724573, 724574, 724575,
                                  724576, 724578, 724640, 724806,
                                  724807, 724808, 724809, 724811,
                                  724820, 724821, 724827, 724833,
                                  724835, 724836, 724840, 724841,
                                  724848, 724849, 724855, 724857,
                                  724858, 724861, 724862, 724865,
                                  724866, 724868, 724909, 724910,
                                  724913, 724914, 724924, 724925,
                                  724926, 724927, 727912, 728519,
                                  728520, 728521, 728522, 728523,
                                  728524, 728525, 728526, 728527,
                                  728528, 728534, 728535, 728536,
                                  728537, 728538, 728539, 728540,
                                  728541, 728542, 728543, 728544,
                                  728545, 728546, 728547, 728548,
                                  728549, 728550, 728551, 728552,
                                  728553, 728554, 728557, 728558,
                                  728559, 728560, 728561, 728562,
                                  728563, 728564
----------------------------------------------------------------------------------------------------------------
(3) PW4158.                      717704, 724001, 724002, 724004,       4,300      5,600      6,600      750
                                  724005, 724006, 724007, 724008,
                                  724009, 724010, 724011, 724019,
                                  724020, 724031, 724035, 724038,
                                  724039, 724042, 724043, 724047,
                                  724068, 724069, 724071, 724076,
                                  724077, 724080, 724085, 724086,
                                  724087, 724092, 724093, 724096,
                                  724097, 724801, 724802, 724803,
                                  724804, 724805, 724813, 724814,
                                  724819, 724823, 724824, 724825,
                                  724826, 724828, 724831, 724832,
                                  724843, 724846, 724847, 724851,
                                  724852, 724853, 724854, 724859,
                                  724860, 724863, 724864, 724867,
                                  724869, 724870, 724871, 724872,
                                  724873, 724874, 724875, 724876,
                                  724880, 724881, 724882, 724883,
                                  724884, 724885, 724886, 724887,
                                  724888, 724889, 724890, 724892,
                                  724893, 724894, 724895, 724896,
                                  724897, 724898, 724899, 724900,
                                  724932, 727315, 727436, 728501,
                                  728502, 728503, 728504, 728505,
                                  728506, 728507, 728508, 728509,
                                  728510, 728511, 728515, 728518,
                                  728531, 728532, 728533
----------------------------------------------------------------------------------------------------------------

[[Page 38902]]

 
(4) PW4156, PW4156A, and         All others not listed by SN in this   1,050      1,600      6,600      750
 PW4158.                          Table.
----------------------------------------------------------------------------------------------------------------
(5) PW4052.                      All engines.                          3,000      4,400      4,400      750
----------------------------------------------------------------------------------------------------------------
(6) PW4056.                      All engines.                          1,800      3,000      3,000      750
----------------------------------------------------------------------------------------------------------------
(7) PW4060, PW4060A, PW4060C,    All engines.                          1,100      2,300      3,000      750
 and PW4062.
----------------------------------------------------------------------------------------------------------------

Minimum Build Standard

    (f) After the effective date of this AD, do not install an 
engine with HPC and HPT modules where the CSO of the HPC is 1,500 
cycles or more greater than the CSO of the HPT.
    (g) After the effective date of this AD, any engine that 
undergoes an HPC overhaul must meet the build standard of the 
following PW SB's: PW4ENG 72-484, PW4ENG 72-486, PW4ENG 72-514, and 
PW4ENG 72-575. Engines that incorporate the Phase 3 configuration 
meet the build standard defined by PW SB PW4ENG 72-514.
    (h) After the effective date of this AD, any engine that 
undergoes separation of the HPC and HPT modules after the effective 
date of this AD, must meet the build standard of PW SB PW4ENG 72-
514. Engines that incorporate the Phase 3 configuration meet the 
build standard defined by PW SB PW4ENG 72-514.
    (i) Within 100 CIS after the effective date of this AD, and 
thereafter, limit the number of engines with configuration D from 
Table 1 of this AD to one on each airplane.
    (j) When a thrust rating change has been made by using the 
Electronic Engine Control (EEC) programming plug in the affected HPC 
overhaul period, the cyclic limits associated with the highest 
thrust rating must be utilized.

Definitions

    (k) For the purposes of this AD, the following definitions 
apply:
    (1) HPC Overhaul--an HPC overhaul is defined as restoration of 
the HPC stages 5 through 15 blade tip clearances to the limits 
specified in the applicable fits and clearances section of the 
engine manual.
    (2) HPT Overhaul--an HPT overhaul is defined as restoration of 
the HPT module stage 1 and 2 HPT blade tip clearances to the 
applicable fits and clearances section of the engine manual.
    (3) A Phase 3 engine is identified by a (-3) suffix after the 
engine model number on the data plate if incorporated at original 
manufacture, or a (-3C) suffix after the engine model number if the 
engine was converted using PW SB's PW4ENG 72-490, PW4ENG 72-504, or 
PW4ENG 72-572 after original manufacture.

Alternative Methods of Compliance

    (l) 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, Engine Certification Office (ECO). 
Operators shall submit their requests through an appropriate FAA 
Maintenance Inspector, who may add comments and then send it to the 
Manager, ECO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the ECO.

Special Flight Permits

    (m) Special flight permits may be issued in accordance with 
Secs. 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.

Effective Date

    (n) This amendment becomes effective August 10, 2001.

    Issued in Burlington, Massachusetts on July 17, 2001.
Francis A. Favara,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 01-18432 Filed 7-25-01; 8:45 am]
BILLING CODE 4910-13-P