FR Doc 03-10234

[Federal Register: April 29, 2003 (Volume 68, Number 82)]
[Rules and Regulations]
[Page 22589-22592]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr29ap03-8]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-NE-15-AD; Amendment 39-13131; AD 2003-09-02]
RIN 2120-AA64

Airworthiness Directives; Pratt and Whitney PW4000 Series
Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), that
is applicable to certain serial number (SN) Pratt and Whitney (PW)
models PW4164, PW4168, and PW4168A turbofan engines. This amendment
requires operators to initially and repetitively borescope-inspect 14th
and 15th stage rubstrips located on the 13th and 14th stage stator set
for wear. This amendment is prompted by reports of high pressure
compressor (HPC) surges during the takeoff phase of flight that have
been attributed to increased stage 14 and stage 15 HPC blade tip
clearances caused by excessive wear on the HPC inner rear case rear
hook. The actions specified by this AD are intended to prevent engine
power loss during takeoff due to HPC surge.

DATES: Effective June 3, 2003. The incorporation by reference of
certain publications listed in the regulations is approved by the
Director of the Federal Register as of June 3, 2003.

ADDRESSES: The 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) 656-4503. This information may be
examined, by appointment, at the Federal Aviation Administration (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: Keith Lardie, Aerospace Engineer,
Engine Certification Office, FAA, Engine and Propeller Directorate, 12
New England Executive Park, Burlington, MA 01803-5299; telephone (781)
238-7189; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) to include an AD that is
applicable to certain SN PW models PW4164, PW4168, and PW4168A turbofan
engines was published in the Federal Register on September 20, 2002 (67
FR 59215). That action proposed to require operators to initially and
repetitively borescope-inspect 14th and 15th stage rubstrips located on
the 13th and 14th stage stator set for wear in accordance with Pratt &
Whitney Alert Service Bulletin (ASB) PW4G-100-A72-170, Revision 2,
dated June 24, 2002. That action also proposed that installation of an
HPC inner rear case assembly in accordance with Pratt & Whitney service
bulletin (SB) No. PW4G-100-72-159, Revision 1, dated July 12, 2000, be
terminating action for the repetitive borescope inspections of this AD.

Comments

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

Terminating Action Too Specifically Tied to SB

One commenter states that the proposed terminating action to modify
or repair the HPC inner rear case hook recognizes only one method of
compliance, which is in accordance with PW SB PW4G-100-72-159. The
commenter requests the addition of Chromalloy Florida Repair Procedure

[[Page 22590]]

00-CFL-039-0 as an approved method to repair the HPC inner rear case.
The FAA agrees. Therefore, the terminating action of the final rule
includes both PW SB PW4G-100-72-159 and Chromalloy Florida Repair
Procedure 00-CFL-039-0, as approved methods to modify or replace the
HPC inner rear case.

Include HPC Inner Rear Case Assembly P/N 58H559-01

One commenter suggests including HPC inner rear case assembly P/N
58H559-01 as an installation option to installing HPC inner rear case
assembly P/N 58H026-01, because P/N 58H559-01 also introduces the rear
hook made from Haynes 242 material, as specified in PW SB No. PW4G-100-
72-187.
The FAA agrees. Therefore, SB PW4G-100-72-187, which incorporates
an HPC inner rear case assembly with an improved durability rear hook,
is added as an additional method for terminating action for the
repetitive borescope inspections of this AD.

Allow for Engines Already Inspected

The same commenter suggests that another category be added to Table
1 that makes allowances for engines already inspected per ASB PW4G-100-
A72-170 before the effective date of this AD. The proposal as-written
has no condition stated for engines already inspected per ASB PW4G-100-
A72-170.
The FAA agrees. However, instead of modifying Table 1, a paragraph
has been added to the final rule that states that engines borescope-
inspected before the effective date of this AD, in accordance with PW
ASB PW4G-100-A72-170, Revision 1, dated November 21, 2001, or Revision
2, dated June 24, 2002, must perform actions in accordance with the
wear limits and disposition instructions of this AD.

Change Replacement Wording and Supply Definition Paragraph

The same commenter suggests that the last phrase in paragraph
(c)(2) be changed from requiring the replacement of the engine with an
engine not affected by this AD, to requiring the replacement of the
engine with a ``non-worn'' engine. The commenter also suggests
supplying a definition for the term ``non-worn'' engine. The
commenter's reason for this suggestion is that he believes that engines
that do not exhibit wear should be acceptable replacements, rather than
mandating as acceptable replacements only engines that have
incorporated the new material hooks.
The FAA partially agrees. The risk analysis assumes that all
engines containing HPC inner rear case rear hooks made from Greek
Ascoloy would be inspected at least every 600 cycles-in-service (CIS)
after the effective date of this AD. The intent of the AD is to remove
engines showing wear of the HPC inner rear case rear hook before a
surge event is caused. Therefore, paragraph (c) is rewritten to require
the replacement of ``engines with HPC inner rear case hook wear beyond
limits'' with ``a serviceable engine''. A definition of serviceable
engine has also been added.

Delete Paragraphs for Borescope Inspections of Uninstalled Engines

The same commenter suggests deleting the paragraphs for borescope
inspections of uninstalled engines, because the wear limits are already
covered previously in the compliance section.
The FAA agrees. The risk analysis treats uninstalled and installed
engines equally by using an average utilization rate. These paragraphs
as originally proposed may result in misinterpretation. Therefore,
these paragraphs are deleted from the final rule.

ASB PW4G-100-A72-170 Revised

Although the proposal incorporated the Accomplishment Instructions
of ASB PW4G-100-A72-170, Revision 2, dated June 24, 2002, by reference,
this final rule incorporates the Accomplishment Instructions of ASB
PW4G-100-A72-170, Revision 3, dated January 31, 2003 by reference.
Revision 3 of ASB PW4G-100-A72-170 includes changes for clarification
purposes and does not affect the original intent of the ASB. These
changes include treating installed and uninstalled engines alike as
discussed in the preceding comments, adding P/N 58H559-01 to the new
material list, and simplifying Table 1.

Move Applicability Information

For clarification, the FAA has deleted paragraph (a) as it appeared
in the proposal and has expanded the Applicability paragraph in the
final rule to state that this AD is applicable to PW models PW4164,
PW4168, and PW4168A turbofan engines, serial numbers P733301 through
P733500 that have HPC inner case assembly P/N 53H272-01 which
incorporates an HPC inner case rear hook susceptible to excessive wear.

Change to Table 1

Table 1 has been simplified to eliminate redundant and potentially
confusing information. The compliance categories for ``engines with
between 900 and 1,500 CSN or CSR'' and ``engines with over 1,500 CSN or
CSR'' have been combined.

Tables 2 and 3 added

Tables 2 and 3 have been added to clarify the repetitive borescope
inspection and removal schedules as outlined in ASB PW4G-100-A72-170.
This information was referenced previously and does not constitute
additional compliance requirements.
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 neither
increase the economic burden on any operator nor increase the scope of
the AD.

Economic Analysis

There are approximately 90 Pratt & Whitney models PW4164, PW4168,
and PW4168A turbofan engines of the affected design in the worldwide
fleet. The FAA estimates that 21 engines installed on airplanes of U.S.
registry would be affected by this AD. The FAA also estimates that it
would take approximately 3 work hours per engine to perform the
inspection, and that the average labor rate is $60 per work hour.
Assuming an average accumulation of 100 cycles-in-service per month per
engine, the FAA estimates an average of two borescope inspections be
required per engine per year. Parts cost is not included in this
analysis, as this AD requires inspection. Based on these figures, the
total cost of the AD to U.S. operators is estimated to be $7,560.

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.
For the reasons discussed above, I certify that this action (1) is
not a ``significant regulatory action'' under Executive Order 12866;
(2) is not a ``significant rule'' under the DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979); and (3) will not have a
significant economic impact, positive or negative, on a

[[Page 22591]]

substantial number of small entities under the criteria of the
Regulatory Flexibility Act. A final evaluation has been prepared for
this action and it is contained in the Rules Docket. A copy of it may
be obtained by contacting 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

0
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

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

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

Sec. 39.13 [Amended]

0
2. Section 39.13 is amended by adding a new airworthiness directive to
read as follows:

2003-09-02 Pratt & Whitney: Amendment 39-13131. Docket No. 2002-NE-
15-AD.

Applicability

This airworthiness directive (AD) is applicable to Pratt and
Whitney (PW) models PW4164, PW4168, and PW4168A turbofan engines,
serial numbers P733301 through P733500, that have HPC inner case
assembly part number (P/N) 53H272-01 installed. These engines are
installed on, but not limited to Airbus Industrie A330 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 (g) 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 power loss during takeoff due to high pressure
compressor (HPC) surge, do the following:
(a) Borescope-inspect in accordance with paragraphs 1.A. through
1.I of the Accomplishment Instructions, Borescope Inspection of
Pratt & Whitney (PW) Alert Service Bulletin (ASB) PW4G-100-A72-170,
Revision 3, dated January 31, 2003, using schedules in the following
Table 1:

Table 1.--Installed-Engine Initial Borescope Inspection Schedule
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Accumulated engine cycles on the Initial borescope-inspect 14th
effective date of this AD: and 15th stage rubstrips:
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(1) Fewer than 900 cycles-since-new Before accumulating 1,500 CSN
(CSN) or cycles-since-refurbishment or CSR, whichever occurs
(CSR) of the HPC inner rear case later.
assembly.
(2) 900 or more CSN or CSR............. Within 600 cycles-in-service
(CIS) after the effective date
of this AD.
------------------------------------------------------------------------

(b) Perform the applicable action as specified in the following
Table 2:

Table 2.--Borescope Inspection Results and Required Action
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Results observed at last borescope
inspection: Action:
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(1) 14th stage rubstrip shows wear Remove engine from service within 250 CIS.
through to the parent material of
the stator, with the
circumferential length of the wear
being 1.0'' or more.
(2) 15th stage rubstrip shows wear Remove engine from service within 250 CIS.
through to the parent material of
the stator, with the
circumferential length of the wear
being 2.0'' or more.
(3) 14th stage rubstrip shows wear Reinspect every 300 CIS.
through to the parent material of
the stator, with the
circumferential length of the wear
being less than 1.0''.
(4) 15th stage rubstrip shows wear Reinspect every 300 CIS.
through to the parent material of
the stator, with the
circumferential length of the wear
being less than 2.0''.
(5) Both 14th and 15th stage Reinspect every 600 CIS.
rubstrips show no wear through to
the parent material of the stator.
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Airplanes With Two Affected Engines Installed

Table 3.--Borescope Inspection Results and Required Actions for Two Affected Engines
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Second engine Second engine
First engine borescope results: borescope schedule: borescope results: Action:
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(1) Wear as specified in Table 2, Within 10 CIS since Wear as specified in Remove either the first or
Steps (1) through (4). borescope inspection Table 2, Steps (1) second engine from service
of first engine. through (4). within 25 CIS since
borescope inspection of
the second engine and
replace with a serviceable
engine. Remove or re-
inspect in accordance with
Table 2 for remaining
engine and if still
applicable perform actions
as specified in paragraph
(c).

[[Page 22592]]

(2) Wear as specified in Table 2, Within 10 CIS since Wear as specified in For both engines, remove or
Steps (1) through (4). borescope inspection Table 2, Step (5). re-inspect in accordance
of first engine. with Table 2 and, if still
applicable, perform
actions as specified in
paragraph (c).
(3) Wear as specified in Table 2, Inspect as specified Wear as specified in For both engines, remove or
Step (5). in Table 1. Table 2. inspect in accordance with
Table 2 and, if still
applicable, perform
actions as specified in
paragraph (c).
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Definition of Serviceable Engine

(d) For the purposes of this AD, a serviceable engine is:
(1) An engine that incorporates an HPC with zero CSN; or
(2) An engine covered by the Terminating Action in accordance
with paragraph (f) of this AD; or
(3) An engine inspected as specified in paragraphs (a) through
(c) of this AD, and is following the 600 CIS re-inspection interval
as specified in Table 2 of this AD.

Engines Borescope-Inspected Before the Effective Date of This AD

(e) Engines borescope-inspected before the effective date of
this AD in accordance with PW ASB PW4G-100-A72-170, Revision 1,or
Revision 2, must follow the requirements of paragraphs (a) through
(c) of this AD, after the effective date of this AD.

Terminating Action

(f) Replacement of HPC inner rear case assembly with an HPC
inner rear case assembly containing a Haynes 242 rear hook,
including assemblies modified or replaced by PW SB No. PW4G-100-72-
159, PW SB No. PW4G-100-72-187, or Chromalloy Repair Procedure 00-
CFL-039-0, constitutes terminating action for the repetitive engine
borescope inspections of this AD.

Alternative Methods of Compliance

(g) 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 request 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

(h) 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.

Documents That Have Been Incorporated by Reference

(i) The inspections must be done in accordance with Pratt &
Whitney alert service bulletin PW4G-100-A72-170, Revision 3, dated
January 31, 2003. This incorporation by reference was approved by
the Director of the Federal Register in accordance with 5 U.S.C.
552(a) and 1 CFR part 51. Copies may be obtained from Pratt &
Whitney, 400 Main St., East Hartford, CT 06108, telephone (860) 565-
6600; fax (860) 656-4503. Copies may be inspected 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.
(j) This amendment becomes effective on June 3, 2003.

Issued in Burlington, Massachusetts, on April 21, 2003.
Robert Guyotte,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 03-10234 Filed 4-28-03; 8:45 am]

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