[Federal Register Volume 67, Number 183 (Friday, September 20, 2002)]
[Proposed Rules]
[Pages 59215-59217]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-23882]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
 
 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
 ========================================================================
 

  Federal Register / Vol. 67, No. 183 / Friday, September 20, 2002 / 
Proposed Rules  

[[Page 59215]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-NE-15-AD]
RIN 2120-AA64


Airworthiness Directives; Pratt and Whitney PW4000 Series 
Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: The Federal Aviation Administration (FAA) proposes to adopt 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 proposal would require operators to initially 
and repetitively borescope-inspect 14th and 15th stage rubstrips 
located on the 13th and 14th stage stator set for wear. This proposal 
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 the 
proposed AD are intended to prevent engine power loss during takeoff 
due to HPC surge.

DATES: Comments must be received by November 19, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 2002-NE-15-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may be inspected at 
this location, by appointment, between 8:00 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 service information referenced in the proposed rule 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 FAA, New England Region, Office of the 
Regional Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Tara Goodman, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
238-7130; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed 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 above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this action may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with 
the substance of this proposal 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 2002-NE-15-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRM's

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, New England Region, Office of the Regional Counsel, 
Attention:
    Rules Docket No. 2002-NE-15-AD, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    The FAA has received reports of eleven HPC surge events occurring 
during the takeoff phase of flight, on PW models PW4164, PW4168, and 
PW4168A turbofan engines. The manufacturer has attributed these surges 
to increased stage 14 and stage 15 HPC blade tip clearances, caused by 
excessive wear on the rear hook of the HPC inner rear case assembly 
part number (P/N) 53H272-01. The rear hook wear allows the 14th and 
15th stage rubstrips, located on the 13th and 14th stage stator in the 
HPC inner rear case assembly, to rub against the blade tips resulting 
in increased blade tip clearances and a reduced surge margin. This 
proposal requires initial and repetitive borescope inspections of the 
14th and 15th stage rubstrips for wear and removing the engine from 
service if the inspection finds 14th and 15th stage rubstrip wear 
beyond specified limits, in order to replace the 13th and 14th stage 
stator set with a serviceable stator set and to replace the HPC inner 
rear case assembly. This proposal also requires, on uninstalled 
engines, borescope inspection of the 14th and 15th stage rubstrips, and 
if any evidence of wear through to parent material is revealed, 
replacement of the HPC inner case assembly with HPC inner case assembly 
P/N 58H026-01, and replacement of the worn 13th and 14th stage stator 
set and with a serviceable 13th and 14th stage stator set. This 
condition, if not corrected, could result in engine takeoff power loss 
due to HPC surge.

Manufacturer's Service Information

    The FAA has reviewed and approved the technical contents of Pratt &
    Whitney Alert Service Bulletin (ASB) PW4G-100-A72-170, Revision 2, 
dated June 24, 2002. The ASB:
    [sbull] Is applicable to engines serial numbers P733301 through 
P733500 not having HPC inner rear case assembly P/N 58H026-01 
installed, and describes procedures for initial and repetitive 
borescope inspections of 14th and 15th stage rubstrips for wear; and
    [sbull] If wear exceeds specified limits, requires removal for 
replacement,

[[Page 59216]]

within certain additional cycles, with a serviceable 13th and 14th 
stage stator set P/N 57H283-01; and
    [sbull] If wear exceeds specified limits, requires removal for 
replacement of the HPC inner rear case assembly P/N 53H272-01 with a 
new design HPC inner rear case assembly P/N 58H026-01.

The FAA has also reviewed and approved the technical contents of Pratt 
& Whitney SB PW4G-100-72-159, Revision 1, dated July 12, 2000, that 
introduces a new HPC inner rear case with different rear hook material, 
by either modification of the case assembly or replacing the HPC inner 
rear case assembly with new design HPC inner rear case assembly P/N 
58H026-01.

FAA's Determination of an Unsafe Condition and Proposed Actions

    Since an unsafe condition has been identified that is likely to 
exist or develop on other PW models PW4164, PW4168, and PW4168A 
turbofan engines of the same type design, the proposed AD would 
require:
    [sbull] Initial and repetitive borescope inspections of 14th and 
15th stage rubstrips, located on the 13th and 14th stage stator set P/N 
57H283-01, for wear; AND
    [sbull] Removing the engine from service if the inspection finds 
14th and 15th stage rubstrip wear beyond specified limits, in order to 
replace the 13th and 14th stage stator set with a serviceable stator 
set and to replace the HPC inner rear case assembly; AND
    [sbull] On uninstalled engines, borescope inspection of the 14th 
and 15th stage rubstrips, and if any evidence of wear through to parent 
material is revealed, replacement of the HPC inner case assembly with 
case assembly P/N 58H026-01, and replacement of the worn 13th and 14th 
stage stator set with a serviceable 13th and 14th stage stator set.

Installation of an HPC inner rear case assembly P/N 58H026-01, and a 
serviceable 13th and 14th stage stator set P/N 57H283-01, constitutes 
terminating action to the repetitive borescope inspections of this 
proposed AD. The actions would be required to be done in accordance 
with the service bulletins described previously.

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 proposed AD. The FAA also estimates 
that it would take approximately 3 work hours per engine to perform the 
proposed 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 proposed AD to U.S. operators is 
estimated to be $7,560.

Regulatory Analysis

    This proposed 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 proposed rule.
    For the reasons discussed above, I certify that this proposed 
regulation (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) if promulgated, will not have a significant economic impact, 
positive or negative, on a substantial number of small entities under 
the criteria of the Regulatory Flexibility Act. A copy of the draft 
regulatory evaluation prepared for this action 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, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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 adding the following new 
airworthiness directive:
Pratt & Whitney: 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. These engines are installed 
on, but not limited to Airbus Industries 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 (f) 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) For engines with an HPC inner case assembly part number (P/
N) 58H026-01 installed, no action is required.

Airplanes With One Affected Engine Installed

    (b) If only one of the engines on the airplane is affected by 
this AD, do the following:
    (1) Perform borescope inspections in accordance with the 
Accomplishment Instructions, Borescope Inspection for Engines 
Installed on Aircraft, paragraphs 1.A. through 1.I of Pratt & 
Whitney Alert Service Bulletin (ASB) PW4G-100-A72-170, Revision 2, 
dated June 24, 2002, using the following Table 1 schedule:

[[Page 59217]]



        Table 1.--Installed-Engine Borescope Inspection Schedule
------------------------------------------------------------------------
                                          Initial borescope-inspect 14th
       Engine cycles accumulated             and 15th stage rubstrips
------------------------------------------------------------------------
(i) 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, on the effective date of
 this AD.
(ii) More than 900 CSN or CSR but fewer  Within 600 cycles-in-service
 than 1,500 CSN or CSR, on the            (CIS) after the effective date
 effective date of this AD.               of this AD.
(iii) More than 1,500 CSN or CSR, on     Within 600 cycles since the
 the effective date of this AD.           last inspection of 14th and
                                          15th stage rubstrips, or 600
                                          CIS after the effective date
                                          of this AD, whichever occurs
                                          earlier.
------------------------------------------------------------------------

    (2) Use the wear limits and disposition the engine in accordance 
with the Accomplishment Instructions, Borescope Inspection for 
Engines Installed on Aircraft, paragraphs 2 through 4 of Pratt & 
Whitney ASB PW4G-100-A72-170, Revision 2, dated June 24, 2002.

Airplanes With Two Affected Engines Installed

    (c) For engines installed on airplanes with two engines affected 
by this AD, do the following:
    (1) Perform borescope inspections in accordance with the 
Accomplishment Instructions, Borescope Inspection for Engines 
Installed on Aircraft, paragraphs 1.A. through 1.I of Pratt & 
Whitney ASB PW4G-100-A72-170, Revision 2, dated June 24, 2002, using 
the schedule in Table 1.
    (2) If a borescope inspection of one engine reveals any evidence 
of wear through to the parent material of either the 14th stage or 
15th stage rubstrip, then borescope-inspect the other engine on the 
aircraft within 10 additional CIS. If the other engine shows any 
evidence of wear through to the parent material of either 14th stage 
or 15th stage rubstrip, then remove either engine from the aircraft 
within 25 additional CIS and replace with an engine not affected by 
this AD.

Borescope Inspections of Uninstalled Engines

    (d) For engines removed from the aircraft and not scheduled for 
HPC disassembly, perform a borescope inspection in accordance with 
the Accomplishment Instructions, Borescope Inspection for Engines 
Removed From the Aircraft and Not Scheduled for HPC Disassembly, 
paragraphs 1.A. through 1.I of Pratt & Whitney ASB PW4G-100-A72-170, 
Revision 2, dated June 24, 2002. Use the wear limits and disposition 
the engine in accordance with paragraphs 2 through 3 of the ASB.
    (e) Thereafter, perform the borescope inspections of paragraphs 
(b), (c), or (d) of this AD within 600 cycles since last inspection.

Terminating Action

    (f) Installation of an HPC inner rear case assembly P/N 58H026-
01 in accordance with Pratt & Whitney service bulletin (SB) No. 
PW4G-100-72-159, Revision 1, dated July 12, 2000 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.

    Issued in Burlington, Massachusetts, on September 13, 2002.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 02-23882 Filed 9-19-02; 8:45 am]
BILLING CODE 4910-13-P