Document ID: FAA-2008-0759-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; Pratt and Whitney (PW) JT9D-7 Series Turbofan Engines
Posted Date: 2008-07-10T04:00Z

[Federal Register: July 10, 2008 (Volume 73, Number 133)]
[Proposed Rules]               
[Page 39627-39628]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr10jy08-19]                         

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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.

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[[Page 39627]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-0759; Directorate Identifier 2008-NE-02-AD]
RIN 2120-AA64

 
Airworthiness Directives; Pratt & Whitney (PW) JT9D-7 Series 
Turbofan Engines

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

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for PW models JT9D-7, -7A, -7AH, -7H, -7F, and -7J turbofan engines. 
This proposed AD would require initial and repetitive borescope 
inspections of the 2nd stage high-pressure turbine (HPT) rotor and 
stator assembly. This proposed AD results from an uncontained failure 
of a 2nd stage HPT rotor disk that caused the engine to separate from 
the airplane. We are proposing this AD to prevent failure of the 2nd 
stage HPT rotor disk, which could result in uncontained engine failure, 
damage to the airplane, and the engine separating from the airplane.

DATES: We must receive any comments on this proposed AD by September 8, 
2008.

ADDRESSES: Use one of the following addresses to comment on this 
proposed AD:
     Federal eRulemaking Portal: Go to http://
www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility, U.S. Department of 
Transportation, 1200 New Jersey Avenue, SE., West Building Ground 
Floor, Room W12-140, Washington, DC 20590-0001.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
     Fax: (202) 493-2251.
    You can get the service information identified in this proposed AD 
from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone 
(860) 565-8770; fax (860) 565-4503.

FOR FURTHER INFORMATION CONTACT: Mark Riley, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; e-mail: 
mark.riley@faa.gov; telephone (781) 238-7758, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to send us any written relevant data, views, or 
arguments regarding this proposal. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2008-0759; Directorate 
Identifier 2008-NE-02-AD'' in the subject line of your comments. We 
specifically invite comments on the overall regulatory, economic, 
environmental, and energy aspects of the proposed AD. We will consider 
all comments received by the closing date and may amend the proposed AD 
in light of those comments.
    We will post all comments we receive, without change, to http://
www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact 
with FAA personnel concerning this proposed AD. Using the search 
function of the Web site, anyone can find and read the comments in any 
of our dockets, including, if provided, the name of the individual who 
sent the comment (or signed the comment on behalf of an association, 
business, labor union, etc.). You may review the DOT's complete Privacy 
Act Statement in the Federal Register published on April 11, 2000 (65 
FR 19477-78).

Examining the AD Docket

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

Discussion

    On October 20, 2004, a PW JT9D-7A engine experienced an uncontained 
failure of the 2nd stage HPT rotor disk. The resulting imbalance caused 
the engine to separate from the airplane. Root cause investigation 
revealed that improper assembly caused the 2nd stage HPT vane 
assemblies to lean back into the 2nd stage HPT rotor disk. The 
investigation found indications of three improper assembly steps within 
the engine that contributed to this vane lean back, disk fracture, 
uncontained event.
     First, the investigation found an improper silver-based 
antigallant.
     Second, the lock wire on the 2nd stage HPT vane retaining 
bolts was not applied correctly.
     Finally, the 2nd stage HPT vane retaining bolts were 
reused.
     Pratt & Whitney determined that the assembly procedures in 
the engine manual (EM) might be misinterpreted and issued new 
procedures to ensure the repair facilities follow proper assembly 
procedures. Because PW was unable to determine the time frame over 
which the repair facility used the old assembly procedures, they 
developed a borescope inspection to identify vane lean back of the 2nd 
stage HPT vanes of all JT9D-7 series engines. This condition, if not 
corrected, could result in uncontained engine failure, damage to the 
airplane, and the engine separating from the airplane.

Relevant Service Information

    We have reviewed and approved the technical contents of PW Alert 
Service Bulletin (ASB) JT9D A6488, Revision 1, dated April 18, 2008, 
that describes the procedures and inspection requirements for borescope 
inspection of the 2nd stage HPT vanes.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other products 
of this same type design. We are proposing this AD, which would require 
an initial and repetitive borescope inspection of the

[[Page 39628]]

2nd stage HPT vane assembly. The proposed AD would require you to use 
the service information described previously to perform these actions.

Interim Action

    These actions are interim actions and we may take further 
rulemaking actions in the future.

Costs of Compliance

    We estimate that this proposed AD would affect 240 engines 
installed on airplanes of U.S. registry. We also estimate that it would 
take about 5 work-hours per engine to perform the proposed actions, 
that each engine might require two inspections, and that the average 
labor rate is $80 per work-hour. Based on these figures, we estimate 
the total cost of the proposed AD to U.S. operators to be $192,000.

Authority for This Rulemaking

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

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD 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.
    For the reasons discussed above, I certify that the proposed AD:
    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. Would not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD. You may get a copy of this summary at the 
address listed under ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Under the authority delegated to me by the Administrator, the 
Federal Aviation Administration proposes to amend 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. The FAA amends Sec.  39.13 by adding the following new 
airworthiness directive:

Pratt & Whitney: Docket No. FAA-2008-0759; Directorate Identifier 
2008-NE-02-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by September 8, 
2008.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Pratt & Whitney (PW) JT9D-7, -7A, -7AH, -
7H, -7F, and -7J turbofan engines. These engines are installed on, 
but not limited to, Boeing 747 series airplanes.

Unsafe Condition

    (d) This AD results from an uncontained failure of a 2nd stage 
high-pressure turbine (HPT) rotor disk that caused the engine to 
separate from the airplane. We are issuing this AD to prevent 
failure of the 2nd stage HPT rotor disk, which could result in 
uncontained engine failure, damage to the airplane, and the engine 
separating from the airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified unless the 
actions have already been done.

Initial Borescope Inspection

    (f) Within 100 cycles-in-service (CIS) after the effective date 
of this AD, or within 1,000 CIS after the last HPT module overhaul, 
whichever occurs later, do the following:
    (1) Use the Accomplishment Instructions of PW Alert Service 
Bulletin (ASB) JT9D A6488, Revision 1, dated April 18, 2008, to 
borescope-inspect the 2nd stage HPT rotor and stator assembly either 
on-wing or in the shop.
    (2) If you see any damage or contact between the 2nd stage HPT 
vanes and the 2nd stage HPT rotor, remove the engine from service.

Repetitive Borescope Inspection

    (g) Thereafter, within 1,000 cycles-since-last inspection, do 
the following:
    (1) Use the Accomplishment Instructions of PW ASB JT9D A6488 
Revision 1, dated April 18, 2008, to borescope-inspect the 2nd stage 
HPT rotor and stator assembly either on-wing or in the shop.
    (2) If you see any damage or contact between the 2nd stage HPT 
vanes and the 2nd stage HPT rotor, remove the engine from service.

Optional Terminating Action

    (h) Installing the 2nd stage HPT vanes as specified in the JT9D-
7 Engine Manual Revision 122, dated February 15, 2008, terminates 
the repetitive inspection requirement specified in paragraph (g) of 
this AD.

Alternative Methods of Compliance

    (i) The Manager, Engine Certification Office, has the authority 
to approve alternative methods of compliance for this AD if 
requested using the procedures found in 14 CFR 39.19.

Related Information

    (j) PW ASB JT9D A6488, Revision 1, dated April 18, 2008, 
pertains to the subject of this AD.
    (k) Contact Mark Riley, Aerospace Engineer, Engine Certification 
Office, FAA, Engine and Propeller Directorate, 12 New England 
Executive Park, Burlington, MA 01803; e-mail: mark.riley@faa.gov; 
telephone (781) 238-7758; fax (781) 238-7199, for more information 
about this AD.

    Issued in Burlington, Massachusetts, on July 3, 2008.
Diane Cook,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. E8-15682 Filed 7-9-08; 8:45 am]

BILLING CODE 4910-13-P