Airworthiness Directives; Pratt and Whitney PW4000 Series Turbofan Engines

[Federal Register Volume 67, Number 207 (Friday, October 25, 2002)]
[Rules and Regulations]
[Pages 65484-65493]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-26909]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NE-47-AD; Amendment 39-12916; AD 2002-21-10]
RIN 2120-AA64


Airworthiness Directives; Pratt and Whitney PW4000 Series 
Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD) that is applicable to Pratt and Whitney (PW) model 4000 series 
turbofan engines. That action required PW4000 engines with potentially 
reduced stability margin to be limited to no more than one engine on 
each airplane, and required removing engines that exceed high pressure 
compressor (HPC) cycles-since-overhaul (CSO) or cycles-since-new (CSN) 
from service based on the engine's configuration and category. That 
action also required establishing a minimum build standard for engines 
that are returned to service, and performing cool-engine fuel spike 
testing (Testing-21) on engines to be returned to service after having 
exceeded HPC cyclic limits or after shop maintenance.
    This amendment establishes requirements similar to those in the 
existing AD being superseded, and introduces a rules-based criterion to 
determine the engine category classification for engines installed on 
Airbus A300 airplanes. This amendment also adds requirements to manage 
the engine configurations installed on Boeing 747 airplanes, and 
requires that repetitive Testing-21 be performed on certain 
configuration engines. This amendment also establishes criteria that 
requires Testing-21 on certain engines with Phase 0 or Phase 1, FB2T, 
or FB2B fan blade configurations. In addition, this amendment re-
establishes high pressure compressor (HPC)-to-high pressure-turbine 
(HPT) cycles-since-overhaul (CSO) cyclic mismatch criteria, and adds 
criteria to address engine installation changes, engine transfers, and 
thrust rating changes. Also, this amendment establishes criteria to 
allow engine stagger without performing Testing-21 for engines which 
are over their respective limits. This amendment also introduces new 
requirements on the Phase 3, first run subpopulation engines which were 
identified after the issuance of NPRM Docket No. 2000-NE-47-AD.
    The Phase 3, first run subpopulation engines have a significant 
increase in surge rate and Testing-21 failure rate than the rest of the 
PW4000 fleet. In order to manage the subpopulation engines to preclude 
a dual-engine surge, immediate action is required.
    This immediately adopted rule includes the requirements proposed in 
the NPRM as well as the required actions for the Phase 3, first run 
subpopulation engines.
    This amendment is prompted by investigation and evaluation of 
PW4000 series turbofan engines surge data, and continuing reports of 
surges in the PW4000 fleet. The actions specified in this AD are 
intended to prevent engine takeoff power losses due to HPC surge.

DATES: Effective November 12, 2002. The incorporation by reference of 
certain publications listed in the rule is approved by the Director of 
the Federal Register as of November 12, 2002.
    The incorporation by reference of certain other publications, as 
listed in the regulations, was approved previously by the Director of 
the Federal Register as of January 17, 2002 (67 FR 1, January 2, 2002).
    Comments for inclusion in the Rules Docket must be received on or 
before December 24, 2002.

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 be inspected at 
this location, by appointment, between 8 a.m. and 4:30 p.m., Monday 
through Friday, except Federal holidays. 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.
    The Pratt & Whitney service information referenced in this AD may 
be obtained from Pratt & Whitney, 400 Main St., East Hartford, CT 
06108, telephone (860) 565-6600; fax (860) 565-4503. All service 
information may be examined, by appointment, at the FAA, New England 
Region, Office of the Regional Counsel, 12 New England Executive Park, 
Burlington, MA; or at the Office of the Federal Register, 800 North 
Capitol Street, NW., Suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Diane Cook, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803-5299; telephone (781) 238-
7133; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD 2001-25-11, 
Amendment 39-12564 (67 FR 1, January 2, 2002), which is applicable to 
Pratt and Whitney (PW) model 4000 series turbofan engines, was 
published in the Federal Register on July 23, 2002. That action 
proposed to establish requirements similar to those in AD 2001-25-11, 
to introduce rules-based criterion to determine the engine category 
classification for engines installed on Airbus A300 airplanes, and to 
add requirements to manage the engine configurations installed on 
Boeing 747 airplanes. That action also proposed to require repetitive 
Testing-21 be performed on certain configuration engines. That action 
also proposed to establish criteria which would require Testing-21 on 
certain engines with Phase 0 or Phase 1, FB2T or FB2B fan blade 
configurations. In addition, that action proposed to re-establish HPC-
to-HPT cycles-since-overhaul cyclic mismatch criteria, and add criteria 
to address engine installation changes, engine transfers, and thrust 
rating changes. Also, that action proposed to establish criteria to 
allow engine stagger without performing Testing-21 for engines over 
their respective limits.
    This final rule; request for comments supersedes AD 2001-25-11 by 
requiring the same actions as the proposal, and in addition, introduces 
new requirements for the Phase 3, first run subpopulation engines that 
were identified after the issuance of the proposal.

Manufacturer's Service Information

    The FAA has reviewed and approved the technical contents of the 
following Pratt & Whitney service information:
    [sbull] Service Bulletin PW4ENG72-714, Revision 1, dated November 
8, 2001.
    [sbull] Service Bulletin PW4ENG72-749, dated June 17, 2002.
    [sbull] Internal Engineering Notice IEN 96KC973D, dated October 12, 
2001.
    [sbull] Temporary Revision (TR) TR 71-0018, dated November 14, 
2001.
    [sbull] TR 71-0026, dated November 14, 2001.

[[Page 65485]]

    [sbull] TR 71 71-0035, dated November 14, 2001.
    [sbull] Cleaning, Inspection, and Repair (CIR) procedure CIR 
51A357, Section 72-35-68, Inspection/Check-04, Indexes 8-11, dated 
September 15, 2001.
    [sbull] CIR 51A357, Section 72-35-68, Repair 16, dated June 15, 
1996.
    [sbull] PW4000 PW engine manual (EM) 50A443, 71-00-00, TESTING-21, 
dated March 15, 2002.
    [sbull] PW4000 PW EM 50A822, 71-00-00, TESTING-21, dated March 15, 
2002.
    [sbull] PW 4000 PW EM 50A605, 71-00-00, TESTING-21, dated March 15, 
2002.

Additional Service Information

    The FAA has reviewed and approved the technical contents of 
Chromalloy Florida Repair Procedures, 00 CFL-039-0, dated December 27, 
2000 and 02 CFL-024-0, dated September 15, 2002.

FAA's Determination of an Unsafe Condition and Required Actions

    Since an unsafe condition has been identified that is likely to 
exist or develop on other Pratt & Whitney PW4000 series turbofan 
engines of this same type design, the AD is issued to prevent engine 
takeoff power losses due to HPC surges, and supersedes AD 2001-25-11 to 
require:
    [sbull] Establishing requirements similar to those in the existing 
AD, and use of a rules-based criterion to determine the engine category 
classification for engines installed on Airbus A300 airplanes.
    [sbull] Adding requirements to manage the engine configurations 
installed on Boeing 747 airplanes. This engine and airplane combination 
would allow, for certain engine configurations, one of the four 
installed engines to remain on-wing until the HPC has accumulated up to 
2,600 CSN or CSO before Testing-21 or until an HPC overhaul is 
required.
    [sbull] Configuration F engines to repeat Testing-21 every 800 CST.
    [sbull] Establishing criteria which would require Testing-21 on 
engines with Phase 0 or Phase 1, FB2T or FB2B fan blade configurations 
complying with the requirements of AD 2001-09-05, (66 FR 22908, May 7, 
2001); AD 2001-09-10, (66 FR 21853, May 2, 2001), or AD 2001-01-10, (66 
FR 6449, January 22, 2001).
    [sbull] Re-establishing HPC-to-HPT CSO cyclic mismatch criteria.
    [sbull] Establishing criteria to address engine installation 
changes, engine transfers, and thrust rating changes.
    [sbull] Establishing criteria to allow an engine to be removed from 
service and reinstalled on an airplane, without requiring Testing-21, 
if this engine is the unmanaged engine for that airplane.
    [sbull] Adding Configuration G engines, which represents the Phase 
3, first run subpopulation engines and establishes requirements that 
reduces stagger limits.
    [sbull] Adding Configuration H engines, which represents the Phase 
3, first run subpopulation engines to repeat Testing-21 every 600 CST.
    The actions are required to be done in accordance with the service 
information described previously, and have been coordinated with the 
Transport Airplane 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 action 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.

Comments

    The FAA received several comments to NPRM, Docket No. 2000-NE-47. 
Even though this amendment is a final rule; request for comments, the 
FAA has chosen to address all comments received. Interested persons 
have been afforded an opportunity to participate in the making of this 
amendment. Due consideration has been given to the comments received, 
from the nine commenters.

Request Reason for Engine Category 1, 2, or 3 Limit Threshold Values

    One commenter states that there is no reason why 200,000 cycles and 
1.45 exhaust pressure ratio (EPR) should be the threshold values used 
in the AD to determine A300 4158 engine category 1, 2, or 3 limits, and 
asks for a technical reason for these values. The FAA disagrees. The 
FAA asked the original equipment manufacturer (OEM) to establish a 
rules-based criterion in which to determine the engine category 
classification for engines installed on Airbus A300 airplanes. The OEM 
chose a statistical approach and derived the values of 200,000 cycles 
and 1.45 EPR to represent the boundary conditions in determining the 
categories. The FAA has reviewed and concurs with this approach. This 
commenter also states that parameters in addition to EPR could better 
define the categorization. This commenter suggests using parameters 
such as rear hook wear and heat shield wear. The FAA disagrees. 
Although the FAA would support using additional parameters, there is 
not enough data to do so. Currently, data supports EPR as a parameter 
to correlate takeoff EPR values to a possible group 3 surge event. 
While the FAA agrees that rear hook wear may contribute to surge 
events, there is not enough data to develop a correlation of rear hook 
wear and heat shield wear to a surge event. The OEM indicates and the 
FAA agrees, that the heat shield wear is a third-order effect. This 
commenter also states that the definition of surge is unclear and that 
noise alone is insufficient to justify a Group 3 surge event. The FAA 
agrees. It was never the intent to imply that noise alone would 
classify an event as a Group 3 surge. The FAA also agrees with this 
first commenter that noise is a good reason to check the DFDR data and 
follow the trouble shooting process. The FAA has reviewed the 
definition of surge and has added words to the Group 3 surge definition 
for clarification.

[[Page 65486]]

Intent To Approve ``On-Wing'' Version of Testing-21

    One commenter questions if it is the FAA's intent to approve the 
``on-wing'' version of Testing-21 and include it into proposed 
paragraph (h)(1) as an equivalent to the ``test cell'' version. The FAA 
is reviewing the data for ``on wing'' version of Testing-21 but has yet 
to approve it. Therefore, ``on wing'' version of Testing-21 is not 
included in this paragraph of the AD. The FAA agrees with the commenter 
that, if approved, the FAA would have added this as an option into the 
paragraph, thereby eliminating the need for alternative methods of 
compliance (AMOC's). Unfortunately adequate data does not yet exist to 
approve the ``on wing'' version of Testing-21. If, at a later date, the 
FAA makes a finding of equivalence, the operator or the OEM can request 
an alternate method of compliance to use the ``on-wing'' version of 
Testing-21 in place of the ``test cell'' Testing-21.

Unnecessary and Confusing Text

    This commenter also states that the following text of AD paragraph, 
under the heading Engines That Surge, ``* * * or before further flight 
if airplane-level troubleshooting procedures require immediate engine 
removal'' is unnecessary and may create confusion. The FAA disagrees. 
It is implied that the airplane level troubleshooting is surge related 
troubleshooting, because the paragraph states ``airplane-level surge''. 
However, to prevent possible confusion, wording in the paragraph has 
been changed to ``airplane level surge troubleshooting.'' This 
commenter also requests that any regulatory action on the Phase 3, fist 
run subpopulation engines be incorporated within this AD. The FAA 
agrees. This AD adds Configurations G and H engines, which represent 
these Phase 3, first run subpopulation engines requiring reduced 
limits. This subpopulation was identified after the issuance of the 
NPRM. Since an unsafe condition has been identified, immediate actions 
are required on these Phase 3, first run subpopulation engines.

Date of AD Should Coincide With Availability of the Ring Style HPC Case

    Another commenter suggests that the effective date of this AD 
should coincide with the availability of the ring style HPC case, since 
this new HPC case is the terminating action. The FAA disagrees. 
Although we agree that the terminating action to this AD requires a 
hardware change to a ring style HPC case, the current rate of risk 
accumulation indicates corrective action must be initiated before 
hardware availability. The ring style HPC case will complete its 
certification within the first quarter of 2003, with Service Bulletins 
issuance expected shortly thereafter. However, AD action is required 
now to minimize the risk. This AD implements action necessary to ensure 
the risk remains at acceptable levels. This commenter also requests 
clarification of the requirements on engines which have passed Testing-
21. The FAA confirms that once an engine has passed Testing-21, it 
becomes a Configuration F or H engine and will remain a Configuration F 
or H engine until the HPC is overhauled, or is replaced with a new or 
overhauled HPC. Configuration F and H engines are required to repeat 
Testing-21 within 800 cycles and 600 cycles respectively, since last 
test or be removed for HPC overhaul, unless it will be used as a single 
unmanaged engine as permitted by this AD. This commenter also requests 
that the FAA consider increasing the hard-time limit for HPC overhaul 
to 2,900 cycles so that any engine which is removed for stagger at HPC 
2,100 cycles since overhaul (CSO) in accordance with the AD, can be 
used up to 2,900 cycles after passing Testing-21. The FAA partially 
agrees. The 2,100 cycles is not a hard-time limit, but a stagger limit 
for PW 4056 Configuration B or C engines installed on Boeing 747 
airplanes in accordance with Table 3 of the NPRM. Unless designated as 
the unmanaged engine, these engines on the Boeing 747 must be removed 
from service before accumulating 2,100 CSN or CSO and perform Testing-
21 or complete an HPC overhaul. If Testing-21 is successful, the engine 
is returned to service as a Configuration F engine. As a Configuration 
F engine, Testing-21 is required within 800 cycles since last test. In 
the commenter's example, 800 cycles since last test would be 2,900 CSO. 
As additional clarification, one of the four installed engines may 
remain on-wing until the HPC has accumulated up to 2,600 CSN or CSO 
before Testing-21 or until an HPC overhaul is required.

Question on Unmanaged Engine Concept

    Another commenter questions why the new unmanaged engine concept of 
the Boeing 747/PW4056 fleet is limited to 2,600 HPC cycles since new or 
since overhaul. Since the Phase 3, first run engine configuration's 
stagger limit is already at 2,600 cycles, this commenter asks the FAA 
to consider similar manageable time allowance for these engines over 
its stagger limit. The FAA disagrees. In order to safely manage the 
fleet risk, PW and Boeing needed to adjust the B747/PW4056 fleet risk. 
It is a coincidence that the Phase 3, first run engine's stagger limit 
is also 2,600 cycles. To safely manage the overall program risk, the 
FAA must maintain the stagger limits and add cycle limits on the 
unmanaged engine configuration installed on the Boeing 747 airplane. In 
addition, since the NPRM was issued, a subpopulation of the Phase 3, 
first run engines has been identified which requires a further limit 
reduction.
    This commenter also states that operators who have been initially 
categorized as an A300 PW4158 category 2 operator should not have to 
reassess their category. The commenter states that since the low surge 
rate of category 2 operators has been proven through their surge 
experience for a dedicated period of time with respective fleet takeoff 
EPR application, it is felt that reevaluation is unnecessary. The 
commenter requests the FAA allow initial category 2 operators to retain 
the same category throughout the field management plan. The FAA agrees 
that if takeoff EPR application does not change, the operator will 
likely remain a category 2 operator. However, additional data suggests 
that an operator may have a shift in its takeoff EPR values due to 
various reasons, like route changes. Since the possibility exists of an 
operator changing their takeoff EPR application, the FAA requires a 
takeoff EPR re-assessment to ensure proper categorization of the 
operator. This commenter objects to the retest requirement of Testing-
21 on any shop-visited engine. This commenter states that without 
detailed analysis on the effect of module separation, retest 
requirement against every engine that has module separation for shop 
minor maintenance would result in an unnecessary burden to the operator 
without any benefit on surge risk reduction. The FAA agrees. However, 
to identify the workscopes that may be exempt from Testing-21 would 
require knowledge of the specific details of each workscope. By using 
the AMOC process, each workscope can be evaluated on a case-by-case 
basis to ensure continued stability of the engine.

Change the Limitation for Configuration F Engines

    Another commenter requests that the FAA change the limitation for 
Configuration F engines from 800 cycles to an option of either 800 
cycles or the applicable threshold in Table 2 or Table 3 in the NPRM, 
whichever is greater. The FAA disagrees. The cyclic limit threshold 
manages overall risk, taking into account the HPC surge margin

[[Page 65487]]

deterioration. Using the commenter's example, this AD requires that if 
a Configuration C engine is in the shop at 300 cycles and performs 
Testing-21, it becomes a Configuration F engine and must repeat 
Testing-21 within 800 cycles. Allowing it to continue in-service until 
its stagger limit of 2,100 cycles before requiring Testing-21, as the 
commenter suggests, doesn't take into account the possible HPC surge 
margin deterioration effects created due to the malfunction that 
brought the engine into the overhaul shop. Depending upon the workscope 
of this engine, a technical argument could be developed to support the 
engine remaining on-wing longer than the 800 cycles. However, this must 
be done on a case-by-case basis to fully evaluate the workscope and its 
effect on engine stability. If the workscope was non-evasive to the 
engine's HPC surge margin, the AMOC process could be used by the 
operator. This commenter also states that the most current published 
dates of the PW4000 engine manual (EM) 50A605, 71-00-00, TESTING-21 
procedure, and PW4000 CIR Manual 51A357, Section 72-35-68 Inspection/
Check-04, are March 15, 2002. The FAA agrees and the appropriate 
changes have been made to the AD.

Question Regarding Off-Wing and On-Wing Maintenance

    This commenter also questions if proposed paragraph (i)(1) is 
applicable to both on-wing and off-wing maintenance. Proposed paragraph 
(i)(1) is only applicable during a shop visit when the HPC is not 
overhauled and a major engine flange separation does not take place. If 
complying with the listed AD's in proposed paragraph (k) Testing-21 is 
required whenever any quantity of fan blades are replaced with new 
blades, overhauled or have the leading edges recontoured. This 
commenter also requests that the FAA consider the following as an 
exception to proposed paragraph (m)(3): Testing-21 would not be 
required on engines with more than 800 cycles remaining to the 
thresholds listed in Tables 2 and 3, when separating a major flange if 
the purpose of the workscope was to repair oil leaks in the forward 
sump, 2.5 bleed system, exhaust case cracks, or to replace fan exit 
vanes, provided no other work was done to the gas path. The commenter 
also states that the exception should also permit the removal of gas 
path items provided they are returned to the same engine. The FAA 
agrees that depending upon the workscope, some exceptions to this 
paragraph can be made. However, specific details of the entire 
workscope would have to be identified to assess the possible effects of 
HPC surge margin. The AMOC process allows for a case-by-case review of 
the overall workscope. Those that do not affect HPC surge margin could 
be candidates for an AMOC. This commenter also suggests an additional 
requirement be added to proposed paragraph (r)(2)(ii). This paragraph 
currently states that Configuration E engines require removal within 25 
cycles, or immediately, based on troubleshooting. But it does not state 
what to do with the engine. The commenter suggests adding a requirement 
to remove the cutback stator configuration from the engine. The FAA 
understands the concern. After the engine removal, HPC overhaul is 
required before return to service. Although not economically practical, 
an HPC overhaul could occur without replacing the cutback stators and 
this engine could be returned to service until it reaches 1,300 cycles-
since-new limit. As long as this engine is removed from service before 
accumulating 1,300 CSN, it meets the risk criteria of the field 
management plan that is acceptable to the FAA. Therefore, this 
paragraph has not been modified but now appears as paragraph 
(q)(2)(ii).

Disagree With Economic Analysis

    A commenter disagrees with the economic analysis as noted in the 
NPRM. The increased restrictions on the Boeing 747 fleet in addition to 
PW's projected Testing-21 failure rate of 30% increased the number of 
Testing-21 performed and increased the required HPC overhauls for the 
years 2002 and 2003. The FAA agrees. The economic analysis also needs 
to include the effects of the reduced limits on the Phase 3, first run 
subpopulation engines. The economic analysis has been revised. Based on 
field data, the non-subpopulation engine Testing-21 failure rate is 12% 
and not 30%. In addition, the subpopulation engine Testing-21 failure 
rate is 20%. The economic analysis has been revised to include these 
failure rates, the increased restrictions on the Boeing 747 fleet, and 
the reduced limits on the Phase 3, first run subpopulation engines. 
Although the FAA recognizes that the subpopulation fleet management 
plan and the added restrictions on the Boeing 747 fleet have increased 
the economic burden to some of the operators, the FAA believes these 
actions are necessary to safely manage the Boeing 747 fleet risk.

Concern for Engines Needing To Use Testing-21 Following Split Shipment

    A commenter is concerned that newly overhauled engines which are 
split at flange E for split shipment transportation reasons must 
perform Testing-21 based on the stability testing requirements of the 
AD. This would become an open loop if the customer had no test cell. 
The FAA agrees, and has added a paragraph to exempt split-shipped 
engines from Testing-21, if the engine's HPC was overhauled or Testing-
21 was successfully passed following the engine shop visit.

Question Regarding Category 2 Criteria

    One commenter is currently operating to the category 2 limits in 
accordance with AD 2001-25-11. Under the requirements of the proposal, 
this operator, who has a small fleet, will not have accumulated 200,000 
cycles and, therefore, will no longer be a category 2 operator. In 
addition, because they will not have enough EPR data to support 
operation to category 1 limits, they will be required to operate to the 
category 3 limits. This operator has asked the FAA to reconsider their 
fleet categorization. The FAA has reviewed this situation with the OEM. 
The OEM has suggested it may be feasible for the operator to obtain a 
sufficient amount of EPR data that can be used as the basis for an AMOC 
to operate to Category 1 limits. By using the AMOC process, the 
feasibility of an alternate method can be evaluated on a case-by-case 
basis.
    One commenter has no objections to the rule as proposed.

Changes to A300 Category 1, 2, 3 Criteria

    In addition, the FAA has reviewed additional data from the OEM 
regarding changes to the A300 Category 1, 2, 3 Takeoff EPR criteria 
based on further assessment of A300 operator takeoff data. The OEM data 
suggests a need to change the limits of the percentage of takeoffs 
greater than 1.45 takeoff EPR data to values that are less conservative 
relative to the original limits in the NPRM. The original NPRM values 
were conservative to allow additional time to access the takeoff EPR 
field data. The FAA has reviewed the data and agrees that changes are 
necessary. Therefore, the limits in paragraphs (f)(9), (h)(1), and 
(h)(2) in this AD have been revised. Also, the FAA has reviewed and 
approved PW SB PW4ENG-72-749 and Chromalloy Florida Repair Procedure 02 
CFL-024-0 as acceptable methods to repair the HPC inner case mid hook. 
Therefore, these procedures are incorporated by reference and are added

[[Page 65488]]

as additional methods of compliance to paragraph (k)(2)(i) of this AD.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes described 
previously. The FAA has determined that these changes will not increase 
the scope of the AD. The FAA has determined, however, that an 
additional opportunity for comment should be afforded because of the 
changes made to this AD.

Economic Analysis

    There are approximately 2,115 engines of the affected design in the 
worldwide fleet. The FAA estimates that 711 engines installed on 
airplanes of U.S. registry would be affected by this AD. The economic 
analysis estimates an annual cost from November 2002 through the end of 
March 2007, (4.4 years or 53 months) at which time the ring style HPC 
case is predicted to be 100% incorporated into the fleet. However, the 
cost of the ring case incorporation is not being assessed within this 
analysis. The FAA estimates 30 test cell stability tests per month 
based on the latest Testing-21 reports from the total fleet. Over 4.4 
years (or 53 months), the FAA estimates a fleetwide total of 1590 test 
cell stability tests or on average 361 test cell stability tests per 
year. For the domestic fleet (33.6% of worldwide fleet), a yearly rate 
of 121 test cell stability tests per year is estimated. Assuming a 12% 
Testing-21 failure rate using the latest statistics, 14 engines per 
year for the domestic fleet would require an HPC overhaul. In addition, 
the FAA estimates 2 surges per month based on April 2001 through 
September 2002 actual Group 3 surge events. Over 4.4 years (or 53 
months), the FAA estimates a total of 106 HPC surges and on average 24 
fleetwide surges per year. For the domestic fleet, the FAA estimates 8 
surges per year. Therefore, the FAA estimates for the domestic fleet 
121 test cell stability tests per year and 22 HPC overhauls per year. 
It is estimated that the cost to industry of a test cell stability test 
will average $15,000 and an HPC overhaul will cost approximately 
$400,000. Based on these figures, the total average annual cost of the 
AD to U.S. operators is estimated to be $10,615,000.

Regulatory Analysis

    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, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

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

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


Sec.  39.13  [Amended]

    2. Section 39.13 is amended by removing Amendment 39-12564 (67 FR 
1, January 2, 2002), and by adding the following new airworthiness 
directive:

2002-21-10 Pratt & Whitney: Amendment 39-12916. Docket No. 2000-NE-
47-AD. Supersedes AD 2001-25-11, Amendment 39-12564.

    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 (s) 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 engine takeoff power losses due to HPC surges, do the 
following:
    (a) When complying with this AD, determine the configuration of 
each engine on each airplane using the following Table 1:

                 Table 1.--Engine Configuration Listing
------------------------------------------------------------------------
                                  Configuration
         Configuration             description          Description
------------------------------------------------------------------------
(1) Phase 1 without high        A                  Engines that did not
 pressure turbine (HPT) 1st                         incorporate the
 turbine vane cut back (1TVCB).                     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 service
                                                    bulletin (SB) PW4ENG
                                                    72-514.
(2) Phase 1 with 1TVCB........  B                  Same as Configuration
                                                    A except that HPT
                                                    1TVCB has been
                                                    incorporated using
                                                    any revision of SB
                                                    PW4ENG 72-514.
(3) Phase 3, 2nd Run..........  C                  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 high pressure
                                                    compressor (HPC)
                                                    overhaul since new.
(4) Phase 3, 1st Run..........  D                  Same as Configuration
                                                    C except that the
                                                    engine has not had
                                                    an HPC overhaul
                                                    since new, except
                                                    those engines that
                                                    are defined as
                                                    Configuration
                                                    Designator G.

[[Page 65489]]

 
(5) HPC Cutback Stator          E                  Engines that
 Configuration Engines.                             currently
                                                    incorporate any
                                                    revision of SB's
                                                    PW4ENG72-706,
                                                    PW4ENG72-704, or
                                                    PW4ENG72-711.
(6) Engines that have passed    F                  Engines which have
 Testing-21.                                        successfully passed
                                                    Testing-21 performed
                                                    in accordance with
                                                    paragraph (i) of
                                                    this AD. Once an
                                                    engine has passed a
                                                    Testing-21, it will
                                                    remain a
                                                    Configuration F
                                                    engine until the HPC
                                                    is overhauled, or is
                                                    replaced with a new
                                                    or overhauled HPC.
(7) Phase 3, 1st Run            G                  Engines that
 Subpopulation Engines. These                       incorporated the
 engines are identified by                          Phase 3
 model and serial numbers                           configuration at the
 (SN's) as follows:                                 time they were
PW4152: SN 724942 through SN                        originally
 724944 inclusive;.                                 manufactured, that
PW4158: SN 728518 through SN                        were built from
 728533 inclusive;.                                 August 29, 1997 up
PW4052, PW4056, PW4060,                             to the incorporation
 PW4060A, PW4060C, PW4062: SN                       of the HPC inner
 727732 through SN 728000                           rear case with the
 inclusive and SN 729001                            Haynes material rear
 through SN 729010 inclusive;.                      hook at the original
PW4460, PW4462: SN 733813                           engine manufacturer
 through SN 733840 inclusive..                      and have not had an
                                                    HPC overhaul since
                                                    new.
(8) Engines from Configuration  H                  Engines that have
 G that have passed Testing-21.                     successfully passed
                                                    Testing-21 performed
                                                    in accordance with
                                                    paragraph (i) of
                                                    this AD. Once an
                                                    engine has passed a
                                                    Testing-21, it will
                                                    remain a
                                                    Configuration H
                                                    engine until the HPC
                                                    is overhauled, or is
                                                    replaced with a new
                                                    or overhauled HPC.
------------------------------------------------------------------------

Configuration E Engines Installed on Boeing 747, 767, and MD-11 
Airplanes

    (b) For Configuration E engines, do the following:
    (1) Before further flight, limit the number of engines with 
Configuration E as described in Table 1 of this AD, to one on each 
airplane.
    (2) Remove all engines with Configuration E from service before 
accumulating 1,300 cycles-since-new (CSN) or cycles-since-conversion 
to Configuration E, whichever is later.
    Configuration G and H Engines Installed on Boeing 747, 767, MD-
11, and Airbus A300 and A310 Airplanes
    (c) For Configuration G engines installed on Boeing 747, 767, 
MD-11, and Airbus A300 and A310 airplanes, except as provided in 
paragraph (b) of this AD:
    (1) Within 30 days after the effective date of this AD, remove 
from service engines that exceed the CSN limits for Configuration G 
engines listed in Row A of the following Table 2.

                                                         Table 2.--Configuration G and H Limits
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                              B767  PW4060
                                  Configuration                                                                 PW4060A     MD-11  PW4460     A300/310
             Row                    designator            B747  PW4056         B767 PW4052    B767  PW4056      PW4060C         PW4462      PW4152 4156A
                                                                                                                 PW4062                        PW4158
--------------------------------------------------------------------------------------------------------------------------------------------------------
A............................  G                    3,000 CSN                4,400 CSN       3,600 CSN       3,000 CSN      2,800 CSN      4,400 CSN
B............................  G                    1,700 CSN                3,000 CSN       2,100 CSN       1,350 CSN      1,150 CSN      2,800 CSN
C............................  H                    600 cycles-since-        600 CST         600 CST         600 CST        600 CST        600 CST
                                                     passing Testing-21
                                                     (CST)
--------------------------------------------------------------------------------------------------------------------------------------------------------

    (2) Within 60 days after the effective date of this AD, remove 
from service engines that exceed the CSN limits for Configuration G 
engines listed in Row B of Table 2 of this AD.
    (3) Thereafter, ensure that no Configuration G engine exceeds 
the HPC CSN limits listed in Row B of Table 2 of this AD.
    (4) Within 60 days after the effective date of this AD, remove 
from service engines that exceed the CST limits for Configuration H 
engines listed in Row C of Table 2 of this AD.
    (5) Thereafter, ensure that no Configuration H engine exceeds 
the CST limits listed in Row C of Table 2 of this AD.
    (6) Configuration G and H engines may be returned to service 
after completing paragraph (i) of this AD.

Engines Installed on Boeing 767 and MD-11 Airplanes

    (d) For engines installed on Boeing 767 and MD-11 airplanes, 
except as provided in paragraph (b) and (c) of this AD, within 50 
airplane cycles after the effective date of this AD, limit the 
number of engines that exceed the HPC CSN, HPC cycles-since-overhaul 
(CSO), or HPC CST limits in Table 3 of this AD, to not more than one 
engine per airplane. Thereafter, ensure that no more than one engine 
per airplane exceeds the HPC CSN, CSO, or CST limit in Table 3 of 
this AD. See paragraph (i) of this AD for return to service 
requirements.

Engines Installed on Boeing 747 Airplanes

    (e) Except as provided in paragraph (b) and (c) of this AD, 
within 50 airplane cycles after the effective date of this AD, and 
thereafter, manage the engine configurations installed on Boeing 747 
airplanes as follows:
    (1) Limit the number of Configuration A, B, C, or E engines that 
exceed the HPC CSN or HPC CSO limits listed in Table 3 of this AD, 
to not more than one engine per airplane. Table 3 follows:

[[Page 65490]]



                                                      Table 3.--Engine Limits for Boeing Airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                         B767-PW4060 PW4060A
     Configuration designator            B747-PW4056            B767-PW4052            B767-PW4056         PW4060C  PW4062       MD-11  PW4460  PW4462
--------------------------------------------------------------------------------------------------------------------------------------------------------
A.................................  1,400 CSN or CSO.....  3,000 CSN or CSO.....  1,600 CSN or CSO....  900 CSN or CSO......  800 CSN or CSO.
B.................................  2,100 CSN or CSO.....  4,400 CSN or CSO.....  2,800 CSN or CSO....  2,000 CSN or CSO....  1,200 CSN or CSO.
C.................................  2,100 CSO............  4,400 CSO............  2,800 CSO...........  2,000 CSO...........  1,300 CSO.
D.................................  2,600 CSN............  4,400 CSN............  3,000 CSN...........  2,200 CSN...........  2,000 CSN.
E.................................  750 CSN or CSO.......  750 CSN or CSO.......  750 CSN or CSO......  750 CSN or CSO......  750 CSN or CSO.
F.................................  800 CST..............  800 CST..............  800 CST.............  800 CST.............  800 CST.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    (2) The single Configuration A, B, C, or E engine per airplane 
that exceeds the HPC CSN or CSO limits listed in Table 3 of this AD, 
must be limited to 2,600 HPC CSN or CSO for Configuration A, B, or C 
engines, or 1,300 HPC CSN or cycles-since-conversion to 
Configuration E, whichever is later, for Configuration E engines.
    (3) Remove from service Configuration D engines before 
accumulating 2,600 CSN.
    (4) Remove from service Configuration F engines before 
accumulating 800 CST.
    (5) Configuration A, B, C, D, and F engines may be returned to 
service after completing paragraph (i) of this AD.

Engines Installed on Airbus A300 and A310 Airplanes

    (f) Use paragraphs (f)(1) through (f)(9) to determine which 
Airbus A300 PW4158 engine category 1, 2, or 3 limits of the 
following Table 4 of this AD apply to your engine fleet:

                                  Table 4.--Engine Limits for Airbus Airplanes
----------------------------------------------------------------------------------------------------------------
                                      A300 PW4158 category
      Configuration designator       1, and A310 PW4156 and   A300 PW4158 category     A300 PW4158 category 3
                                             PW4156A           2, and A310 PW4152
----------------------------------------------------------------------------------------------------------------
A..................................  900 CSN or CSO........  1,850 CSN or CSO.....  500 CSN or CSO.
B..................................  2,200 CSN or CSO......  4,400 CSN or CSO.....  1,600 CSN or CSO.
C..................................  2,200 CSO.............  4,400 CSO............  1,600 CSO.
D..................................  4,400 CSN.............  4,400 CSN............  4,400 CSN.
E..................................  Not Applicable........  Not Applicable.......  Not Applicable.
F..................................  800 CST...............  800 CST..............  800 CST.
----------------------------------------------------------------------------------------------------------------

    (1) Determine the number of Group 3 takeoff surges experienced 
by engines in your fleet before April 13, 2001. Count surge events 
for engines that had an HPC overhaul and incorporated either SB PW 
4ENG 72-484 or SB PW4ENG 72-575 at the time of overhaul. Do not 
count surge events for engines that did not have the HPC overhauled 
(i.e. 1st run engine) or had the HPC overhauled but did not 
incorporate either SB PW4ENG 72-484 or SB PW4ENG 72-575. See 
paragraph (r)(5) of this AD for a definition of a Group 3 takeoff 
surge.
    (2) Determine the number of cumulative HPC CSO accrued by 
engines in your fleet before April 13, 2001. Count HPC CSO for 
engines that had an HPC overhaul and incorporated either SB PW4ENG 
72-484 or SB PW4ENG 72-575 at the time of overhaul. Do not count HPC 
CSO accrued on your engines while operating outside your fleet.
    (3) Calculate the surge rate by dividing the number of Group 3 
takeoff surges determined in paragraph (f)(1) of this AD, by the 
number of cumulative HPC CSO determined in paragraph (f)(2) of this 
AD, and then multiply by 1,000.
    (4) If the surge rate calculated in paragraph (f)(3) of this AD 
is less than 0.005, go to paragraph (f)(5) of this AD. If the surge 
rate calculated in paragraph (f)(3) of this AD is greater than or 
equal to 0.005, go to paragraph (f)(6) of this AD.
    (5) If the cumulative HPC CSO determined in paragraph (f)(2) of 
this AD is greater than or equal to 200,000 cycles, use A300 PW4158 
Category 2 limits of Table 4 of this AD. If less than 200,000 
cycles, go to paragraph (f)(7) of this AD.
    (6) If the surge rate calculated in paragraph (f)(3) of this AD 
is greater than 0.035, use A300 PW 4158 Category 3 limits of Table 4 
of this AD. If less than or equal to 0.035, go to paragraph (f)(7) 
of this AD.
    (7) Determine the percent of takeoffs with greater than a 1.45 
Takeoff engine pressure ratio (EPR) data for engines operating in 
your fleet. Count takeoffs from a random sample of at least 700 
airplane takeoffs that has occurred over at least a 3-month time 
period, for a period beginning no earlier than 23 months prior to 
the effective date of this AD. See paragraph (r)(6) of this AD for 
definition of Takeoff EPR data.
    (8) If there is insufficient data to satisfy the criteria of 
paragraph (f)(7) of this AD, use A300 PW4158 Category 3 limits of 
Table 4 of this AD.
    (9) If the percentage of takeoffs with greater than a 1.45 
Takeoff EPR data determined in paragraph (f)(7) of this AD is 
greater than 31%, use A300 PW 4158 Category 3 limits listed in Table 
4 of this AD. If the percentage of takeoffs with greater than a 1.45 
Takeoff EPR data determined in paragraph (f)(7) of this AD is less 
than or equal to 31%, use A300 PW 4158 Category 1 limits listed in 
Table 4 of this AD.
    (g) For engines installed on Airbus A300 or A310 airplanes, 
except as provided in paragraph (c) of this AD, within 50 airplane 
cycles after the effective date of this AD, limit the number of 
engines that exceed the CSN, CSO, or CST limits listed in Table 4 of 
this AD, to no more than one engine per airplane. Thereafter, ensure 
that no more than one engine per airplane exceeds the HPC CSN, CSO, 
or CST limits listed in Table 4 of this AD. See paragraph (i) of 
this AD for return to service requirements.
    (h) For Airbus A300 PW4158 engine operators, except those 
operators whose engine fleets are determined to be Category 3 
classification based on surge rate in accordance with paragraph 
(f)(6) of this AD, re-evaluate your fleet category within 6 months 
from the effective date of this AD, and thereafter, at intervals not 
to exceed 6 months, using the following criteria:
    (1) For operators whose engine fleets are initially classified 
as Category 1 or 3 in accordance with paragraph (f) of this AD, 
determine the percent of takeoffs with greater than a 1.45 Takeoff 
EPR data for engines operating in your fleet. Count takeoffs from a 
sample of at least 200 takeoffs that occurred over the most recent 
six month time period since the last categorization was determined, 
or the total number of takeoffs accumulated over 6 months if less 
than 200 takeoffs. See

[[Page 65491]]

paragraph (r)(6) of this AD for definition of takeoff EPR data.
    (i) If there is insufficient data to satisfy the criteria of 
paragraph (h)(1) of this AD, use A300 PW4158 Category 3 limits 
listed in Table 4 of this AD.
    (ii) If the percentage of takeoffs with greater than a 1.45 
Takeoff EPR data determined in paragraph (h)(1) of this AD is 
greater than 31%, use A300 PW4158 Category 3 limits listed in Table 
4 of this AD.
    (iii) If the percentage of takeoffs with greater than a 1.45 
Takeoff EPR data determined in paragraph (h)(1) of this AD is less 
than or equal to 31%, use A300 PW4158 Category 1 limits listed in 
Table 4 of this AD.
    (2) For operators whose engine fleets are initially classified 
as Category 2 in accordance with paragraph (f) of this AD, determine 
the percent of takeoffs with greater than a 1.45 Takeoff EPR data 
for engines operating in your fleet. Count takeoffs from a sample of 
at least 200 takeoffs that occurred over the most recent six month 
time period since the last categorization was determined, or the 
total number of takeoffs accumulated over 6 months if less than 200 
takeoffs. See paragraph (r)(6) of this AD for definition of takeoff 
EPR data.
    (i) If there is insufficient data to satisfy the criteria of 
paragraph (h)(2) of this AD, use A300 PW4158 Category 3 limits 
listed in Table 4 of this AD.
    (ii) If the percentage of takeoffs with greater than a 1.45 
Takeoff EPR data determined in paragraph (h)(2) of this AD is 
greater than 37%, use A300 PW4158 Category 3 limits listed in Table 
4 of this AD.
    (iii) If the percentage of takeoffs with greater than a 1.45 
Takeoff EPR data determined in paragraph (h)(2) of this AD is 
greater than or equal to 21% and less than or equal to 37%, use A300 
PW4158 Category 1 limits listed in Table 4 of this AD.
    (iv) If the percentage of takeoffs with greater than a 1.45 
Takeoff EPR data determined in paragraph (h)(2) of this AD is less 
than 21%, use A300 PW4158 Category 2 limits listed in Table 4 of 
this AD.

Return to Service Requirements for All Engines (Testing-21)

    (i) Engines removed from service in accordance with paragraph 
(c), (d), (e), or (g) of this AD may be returned to service under 
the following conditions:
    (1) After passing a cool-engine fuel spike stability test 
(Testing-21) that has been done in accordance with one of the 
following PW4000 Engine Manuals (EM) as applicable, except for 
engines configured with Configuration E, or engines that have 
experienced a Group 3 takeoff surge:
    (i) PW4000 EM 50A443, 71-00-00, TESTING-21, dated March 15, 
2002.
    (ii) PW4000 EM 50A822, 71-00-00, TESTING-21, dated March 15, 
2002.
    (iii) PW4000 EM 50A605, 71-00-00, TESTING-21, dated March 15, 
2002; or
    (2) Engines tested before the effective date of this AD, in 
accordance with any of the following PW4000 EM Temporary Revisions, 
meet the requirements of Testing-21:
    (i) PW4000 EM 50A443, Temporary Revision No. 71-0026, dated 
November 14, 2001.
    (ii) PW4000 EM50A822, Temporary Revision No. 71-0018, dated 
November 14, 2001.
    (iii) PW4000 EM50A605, Temporary Revision No. 71-0035, dated 
November 14, 2001; or
    (3) Engines tested before the effective date of this AD, in 
accordance with PW IEN 96KC973D, dated October 12, 2001, meet the 
requirements of Testing-21; or
    (4) The engine HPC was replaced with an HPC that is new from 
production with no time in service; or
    (5) The engine HPC has been overhauled, or the engine HPC 
replaced with an overhauled HPC with zero cycles since overhaul; or
    (6) An engine that is either below or exceeds the limits of 
Table 3 or Table 4 of this AD may be removed and installed on 
another airplane without Testing-21, as long as the requirements of 
paragraph (c), (d), (e), or (g) of this AD are met at the time of 
engine installation.

Phase 0 or Phase 1, FB2T or FB2B Fan Blade Configurations

    (j) For engines with Phase 0 or Phase 1, FB2T or FB2B fan blade 
configurations complying with the requirements of AD 2001-09-05, (66 
FR 22908, May 5, 2001), AD 2001-09-10, (66 FR 21853, May 2, 2001), 
or AD 2001-01-10, (66 FR 6449, January 22, 2001), do the following:
    (1) Operators complying with the AD's listed in paragraph (j) of 
this AD using the weight restriction compliance method, must perform 
Testing-21 in accordance with paragraph (i)(1) of this AD whenever 
any quantity of fan blades are replaced with new fan blades, 
overhauled fan blades, or with fan blades having the leading edges 
recontoured after the effective date of this AD, if during the shop 
visit the HPC is not overhauled and separation of a major engine 
flange, located between ``A'' flange and ``T'' flange, does not 
occur.
    (2) If an operator changes from the weight restriction 
compliance method to the fan blade leading edge recontouring method 
after the effective date of this AD, testing-21 in accordance with 
paragraph (i)(1) of this AD is required each time fan blade leading 
edge recontouring is done, if the fan blades accumulate more than 
450 cycles since new or since fan blade overhaul, or since the last 
time the fan blade leading edges were recontoured.

Minimum Build Standard

    (k) Use the following minimum build standards:
    (1) 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 greater than the CSN or CSO of the HPT.
    (2) For any engine that undergoes an HPC overhaul after the 
effective date of this AD:
    (i) Inspect the HPC mid hook and rear hook of the HPC inner case 
for wear in accordance with PW Clean, Inspect and Repair (CIR) 
Manual PN 51A357, section 72-35-68 Inspection/Check-04, indexes 8-
11, dated September 15, 2001. If the HPC rear hook is worn beyond 
serviceable limits, replace the HPC inner case rear hook with an 
improved durability hook in accordance with PW SB PW4ENG 72-714, 
Revision 1, dated November 8, 2001, or Chromalloy Florida Repair 
Procedure 00 CFL-039-0, dated December 27, 2000. If the HPC inner 
case mid hook is worn beyond serviceable limits, repair the HPC 
inner case mid hook in accordance with PW CIR PN 51A357 section 72-
35-68, Repair-16, dated June 15, 1996, or in accordance with PW SB 
PW4ENG 72-749, dated June 17, 2002, or Chromalloy Florida Repair 
Procedure 02 CFL-024-0, dated September 15, 2002.
    (ii) After the effective date of this AD, any engine that 
undergoes an HPC overhaul may not be returned to service unless it 
meets the build standard of PW SB PW4ENG 72-484, PW4ENG 72-486, 
PW4ENG 72-514, and PW4ENG 72-575. Engines that incorporate the Phase 
3 configuration already meet the build standard defined by PW SB 
PW4ENG 72-514.
    (3) After the effective date of this AD, any engine that 
undergoes separation of the HPC and HPT modules must not be 
installed on an airplane unless it meets the build standard of PW SB 
PW4ENG 72-514. Engines that incorporate the Phase 3 configuration 
already meet the build standard defined by PW SB PW4ENG 72-514.

Stability Testing Requirements

    (l) After the effective date of this AD, Testing-21 must be 
performed in accordance with paragraph (i)(1) of this AD, before an 
engine can be returned to service after having undergone maintenance 
in the shop, except under any of the following conditions:
    (1) The engine HPC was overhauled, or replaced with an 
overhauled HPC with zero cycles since overhaul; or
    (2) The engine HPC was replaced with an HPC that is new from 
production with no time in service; or
    (3) The shop visit did not result in the separation of a major 
engine flange located between ``A'' flange and ``T'' flange; or
    (4) Engines with an HPC having zero CSN or CSO, or engines that 
successfully passed Testing-21 with zero CST; and are split at 
Flange E for transportation reasons as specified in the applicable 
Storage/Transport section of the applicable Engine Manual.

Thrust Rating Changes, Installation Changes, and Engine Transfers

    (m) When a thrust rating change has been made by using the 
Electronic Engine Control (EEC) programming plug, or an installation 
change has been made during an HPC overhaul period, use the lowest 
cyclic limit of Table 3 or Table 4 of this AD, associated with any 
engine thrust rating change or with any installation change made 
during the affected HPC overhaul period. See paragraph (r)(1) for 
definition of HPC overhaul period.
    (n) When a PW4158 engine is transferred to another PW4158 engine 
operator whose engine fleet has a different category, use the lowest 
cyclic limit in Table 4 of this AD that was used or will be used 
during the affected HPC overhaul period.
    (o) When a PW 4158 engine operator whose engine fleet changes 
category in accordance with paragraph (h) of this AD,

[[Page 65492]]

use the lowest cyclic limits in Table 4 of this AD that were used or 
will be used during the affected HPC overhaul period.
    (p) Engines with an HPC having zero CSN or CSO at the time of 
thrust rating change, or installation change, or engine transfer 
between PW4158 engine operators, or subsequent change in operator 
engine fleet category in accordance with paragraph (h) of this AD in 
the direction of lower to higher Table 4 limits, are exempt from the 
lowest cyclic limit requirement in paragraphs (m), (n), and (o) of 
this AD.

Engines That Surge

    (q) For engines that experience a surge, and after 
troubleshooting procedures are completed for airplane-level surge 
during forward or reverse thrust, do the following:
    (1) For engines that experience a Group 3 takeoff surge, remove 
the engine from service before further flight and perform an HPC 
overhaul.
    (2) For any engine that experiences a forward or reverse thrust 
surge at EPR's greater than 1.25 that is not a Group 3 takeoff 
surge, do the following:
    (i) For Configuration A, B, C, D, F, G, and H engines, remove 
engine from service within 25 CIS or before further flight if 
airplane-level troubleshooting procedures require immediate engine 
removal, and perform Testing-21 in accordance with paragraph (i)(1) 
of this AD.
    (ii) For Configuration E engines, remove engine from service 
within 25 CIS or before further flight if airplane-level 
troubleshooting procedures require immediate engine removal.

Definitions

    (r) For the purposes of this AD, the following definitions 
apply:
    (1) 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) An HPC overhaul period is defined as the time period between 
HPC overhauls.
    (3) An HPT overhaul is defined as restoration of the HPT stage 1 
and 2 blade tip clearances to the limits specified in the applicable 
fits and clearances section of the engine manual.
    (4) 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 ``CN'' suffix after the engine serial number if 
the engine was converted using PW SB's PW4ENG 72-490, PW4ENG 72-504, 
or PW4ENG 72-572 after original manufacture.
    (5) A Group 3 takeoff surge is defined as the occurrence of any 
of the following engine symptoms that usually occur in combination 
during an attempted airplane takeoff operation (either at reduced, 
derated or full rated takeoff power setting) after takeoff power 
set, which can be attributed to no specific and correctable fault 
condition after completing airplane-level surge during forward 
thrust troubleshooting procedures:
    (i) Engine noises, including rumblings and loud ``bang(s).''
    (ii) Unstable engine parameters (EPR, N1, N2, and fuel flow) at 
a fixed thrust setting.
    (iii) Exhaust gas temperature (EGT) increase.
    (iv) Flames from the inlet, the exhaust, or both.
    (6) Takeoff EPR data is defined as Maximum Takeoff EPR if 
takeoff with Takeoff-Go-Around (TOGA) is selected or Flex Takeoff 
EPR if takeoff with Flex Takeoff (FLXTO) is selected. Maximum 
Takeoff EPR or Flex Takeoff EPR may be recorded using any of the 
following methods:
    (i) Manually recorded by the flight crew read from the Takeoff 
EPR power management table during flight preparation (see Aircraft 
Flight Manual (AFM) chapter 5.02.00 and 6.02.01, or Flight Crew 
Operation Manual (FCOM) chapter 2.09.20) and then adjusted by adding 
0.010 to the EPR value recorded; or
    (ii) Automatically recorded during Takeoff at 0.18 Mach Number 
(Mn) (between 0.15 and 0.20 Mn is acceptable) using an aircraft 
automatic data recording system and then adjusted by subtracting 
0.010 from the EPR value recorded; or
    (iii) Automatically recorded during takeoff at maximum EGT, 
which typically occurs at 0.25-0.30 Mn, using an aircraft automatic 
data recording system.

Alternative Methods of Compliance

    (s) 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 must submit their requests through an appropriate FAA 
Principal 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

    (t) Special flight permits may be issued in accordance with 
Sec. Sec.  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 done.

Testing-21 Reports

    (u) Within 60 days of test date, report the results of the cool-
engine fuel spike stability assessment tests (Testing-21) to the 
ANE-142 Branch Manager, Engine Certification Office, 12 New England 
Executive Park, Burlington, MA 01803-5299, or by electronic mail to 
[email protected]. Reporting requirements have been 
approved by the Office of Management and Budget and assigned OMB 
control number 2120-0056. Be sure to include the following 
information:
    (1) Engine serial number.
    (2) Engine configuration designation per Table 1 of this AD.
    (3) Date of the cool-engine fuel spike stability test.
    (4) HPC Serial Number, and HPC time and cycles-since-new and 
since-compressor-overhaul at the time of the test.
    (5) Results of the test (Pass or Fail).

Documents That Have Been Incorporated by Reference

    (v) The actions must be done in accordance with the following 
Pratt and Whitney (PW) service bulletin (SB), Internal Engineering 
Notice (IEN), Temporary Revisions (TR's), Clean, Inspection, and 
Repair Manual (CIR) repair procedures, engine manual (EM) sections, 
and Chromalloy Florida Repair Procedure:

----------------------------------------------------------------------------------------------------------------
           Document No.                      Pages                    Revision                    Date
----------------------------------------------------------------------------------------------------------------
PW SB PW4ENG72-714...............  1-2......................  1.......................  Nov. 8, 2001.
                                   3........................  Original................  June 27, 2000.
                                   4........................  1.......................  Nov. 8, 2001.
                                   5-12.....................  Original................  June 27, 2001.
    Total pages: 12
PW SB PW4ENG72-749...............  All......................  Original................  June 17, 2002.
    Total pages: 12
PW IEN 96KC973D..................  All......................  Original................  Oct. 12, 2001.
    Total pages: 19
PW TR 71-0018....................  All......................  Original................  Nov. 14, 2001.
    Total pages: 24
PW TR 71-0026....................  All......................  Original................  Nov. 14, 2001.
    Total pages: 24
PW TR 71-0035....................  All......................  Original................  Nov. 14, 2001.
    Total pages: 24
PW CIR 51A357, Section 72-35-68,   All......................  Original................  Sept. 15, 2001.
 Inspection/Check-04, Indexes 8-
 11.
    Total pages: 5
PW CIR 51A357, Section 72-35-68,   All......................  Original................  June 15, 1996.
 Repair 16.

[[Page 65493]]

 
    Total pages: 1
PW4000 EM 50A443, 71-00-00,        All......................  Original................  Mar. 15, 2002.
 TESTING-21.
    Total pages: 20
PW4000 EM 50A822, 71-00-00,        All......................  Original................  Mar. 15, 2002.
 TESTING-21.
    Total pages: 20
PW4000 EM 50A605, 71-00-00,        All......................  Original................  Mar. 15, 2002.
 TESTING-21.
    Total pages: 20
Chromalloy Florida Repair
 Procedure, 00 CFL-039-0
Summary..........................  1-3......................  Original................  Dec. 27, 2000.
Insp/chk-01......................  801......................  Original................  Dec. 27, 2000.
Repair-01........................  901-903..................  Original................  Dec. 27, 2000.
    Total pages: 7
Chromalloy Florida Repair
 Procedure, 02 CFL-024-0
Summary..........................  1-5......................  Original................  Sept. 15, 2002.
Inspection.......................  801-802..................  Original................  Sept. 15, 2002.
Repair...........................  901-906..................  Original................  Sept. 15, 2002.
    Total pages: 13
----------------------------------------------------------------------------------------------------------------

The incorporation by reference of SB PW4ENG72-714, dated November 8, 
2001, IEN 96KC973D, dated October 12, 2001, TR 71-0018, TR 71-0026, 
and TR 71-0035, all dated November 14, 2001, CIR 51A357, section 72-
35-68, Inspection/Check-04, Indexes 8-11, dated September 15, 2001, 
and CIR 51A357, section 72-35-68, Repair 16, dated June 15, 1996 was 
approved by the Director of the Federal Register as of January 17, 
2002 (67 FR 1, January 2, 2002). The incorporation by reference of 
SB PW4ENG72-749, dated June 17, 2002, EM 50A443, section 71-00-00, 
Testing-21, EM 50A822, section 71-00-00, Testing-21, EM 50A605, and 
section 71-00-00, Testing-21, all dated March 15, 2002, Chromalloy 
Florida Repair Procedure, 00 CFL-039-0, dated December 27, 2000, and 
Chromalloy Florida Repair Procedure, 02 CFL-024-0, dated September 
15, 2002, was approved by the Director of the Federal Register on 
November 12, 2002, in accordance with 5 U.S.C. 552(a) and 1 CFR part 
51. Pratt and Whitney document copies may be obtained from Pratt and 
Whitney, 400 Main St., East Hartford, CT 06108; telephone (860) 565-
6600; fax (860) 565-4503. Chromalloy Florida document copies may be 
obtained from Chromalloy Florida, 630 Anchors St., NW., Walton 
Beach, FL 32548; telephone (850) 244-7684; fax (850) 244-6322. 
Copies may be inspected, by appointment, at the FAA, New England 
Region, Office of the Regional Counsel, 12 New England Executive 
Park, Burlington, MA; or at the Office of the Federal Register, 800 
North Capitol Street, NW., Suite 700, Washington, DC.

Effective Date

    (w) This amendment becomes effective on November 12, 2002.

    Issued in Burlington Massachusetts, on October 11, 2002.
Mark C. Fulmer,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 02-26909 Filed 10-24-02; 8:45 am]
BILLING CODE 4910-13-P

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