03-22621. Airworthiness Directives; Pratt & Whitney JT9D-3A, -7, -7A, -7AH, -7H, -7F, -7J, -20, and -20J Turbofan Engines

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for Pratt & Whitney (PW) JT9D-3A, -7, -7A, -7AH, -7H, -7F, -7J, -20, and -20J turbofan engines. This proposed AD would clarify a life limit for certain part numbers of 6th stage low pressure turbine (LPT) air seals, and require their removal from service before accumulating 15,000 cycles-since-new (CSN). This proposed AD is prompted by reports of certain 6th stage LPT air seals possibly not being life tracked due to confusion from updates to the engine manuals. We are proposing this AD to prevent failure of the 6th stage LPT air seal, which could cause LPT damage resulting in an uncontained engine failure.

DATES:

We must receive any comments on this proposed AD by November 4, 2003.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD:

• By mail: Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2003-NE-34-AD, 12 New England Executive Park, Burlington, MA 01803-5299.
• By fax: [phone].
• By e-mail: [e-mail].

You can get the service information identified in this proposed AD from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone [phone]; fax [phone].

You may examine the AD docket at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT:

Keith Lardie, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any written relevant data, views, or arguments regarding this proposal. Send your comments to an address listed under ADDRESSES. Include “AD Docket No. 2003-NE-34-AD” in the subject line of your comments. If you want us to acknowledge receipt of your mailed comments, send us a self-addressed, stamped postcard with the docket number written on it; we will date-stamp your postcard and mail it back to you. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. If a person contacts us verbally, and that contact relates to a substantive part of this proposed AD, we will summarize the contact and place the summary in the docket. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We are reviewing the writing style we currently use in regulatory documents. We are interested in your comments on whether the style of this document is clear, and your suggestions to improve the clarity of our communications that affect you. You may get more information about plain language at http://www.faa.gov/​language and http://www.plainlanguage.gov.

Examining the AD Docket

You may examine the AD Docket (including any comments and service information), by appointment, between 8 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. See ADDRESSES for the location.

Discussion

The FAA has recently been made aware that the life limit for 6th stage LPT air seals, part numbers (P/Ns) 808846, 809171, 811260 and 811261, may not be clearly stated in Chapter 5 of the engine manuals. Proper life tracking of these parts is required to ensure safe operation of engines, but because of changes to the engine manuals some operators may have believed that some 6th stage LPT air seals may not require life tracking. This condition, if not corrected, could result in failure of the 6th stage LPT air seal, which could cause LPT damage resulting in an uncontained engine failure.

Relevant Service Information

We have reviewed and approved the technical contents of PW Service Bulletin No. JT9D 6448, dated June 10, 2003, that describes procedures for calculating 6th stage LPT air seal part life for air seals that have not been previously life tracked.

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. Therefore, we are proposing this AD, which would clarify the life limit for 6th stage LPT air seals, P/Ns 808846, 809171, 811260, and 811261, and require their removal from service before accumulating 15,000 CSN. The proposed AD would require you to use the service information described previously for calculating 6th stage LPT air seal part life for parts that have not been previously life tracked.

Changes to 14 CFR Part 39—Effect on the Proposed AD

On July 10, 2002, we published a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs the FAA's AD system. This regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. This material previously was included in each individual AD. Since this material is included in 14 CFR part 39, we will not include it in future AD actions.

Costs of Compliance

There are about 1,024 engines of the affected design in the worldwide fleet. We estimate that 367 engines installed on airplanes of U.S. registry would be affected by this proposed AD. We also estimate that it would take approximately 0.5 work hour per engine to calculate the 6th stage LPT air seal part life, and that the average labor rate is $65 per work hour. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $11,928.

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 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. 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 summary of the costs to comply with this proposal and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include “AD Docket No. 2003-NE-34-AD” in your request.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, 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.

§ 39.13

[Amended]

2. The FAA amends § 39.13 by adding the following new airworthiness directive:

Pratt & Whitney: Docket No. 2003-NE-34-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by November 4, 2003.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Pratt & Whitney (PW) JT9D-3A, -7, -7A, -7AH, -7H, -7F, -7J, -20, and -20J turbofan engines. These engines are installed on, but not limited to, Boeing 747-100, 747-200, 747SR, 747SP, and DC10-40 series airplanes.

Unsafe Condition

(d) This proposed AD is prompted by reports of certain 6th stage low pressure turbine (LPT) air seals possibly not being life tracked due to confusion from updates to the engine manuals. Chapter 5 of Engine Manuals part numbers (P/Ns) 646028, 770407, and 770408 will be revised to show a life limit of 15,000 cycles-since-new (CSN) for 6th stage air seal P/N's 808846, 809171, 811260 and 811261. We are issuing this AD to prevent failure of the 6th stage LPT air seal which could cause LPT damage, resulting in an uncontained engine failure.

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.

Determine Service Life

(f) For 6th stage LPT air seals, P/Ns 808846, 809171, 811260, and 811261, with an unknown number of cycles since installed, calculate the service life within 60 days after the effective date of this AD.

(1) Use Method 1 of the Accomplishment Instructions of PW Service Bulletin (SB) No. JT9D 6448, dated June 10, 2003, for when all service records are available for the specific air seal, to calculate the service life.

(2) Use Method 2 of the Accomplishment Instructions of PW SB No. JT9D 6448, dated June 10, 2003, for when any or all service records are not available for a specific air seal, to calculate the service life. If the worst-case daily utilization rate is unknown, use the fleet worst-case daily utilization rate of 2.9 cycles/day.

Removal From Service

(g) Remove 6th stage LPT air seals, P/Ns 808846, 809171, 811260, and 811261, from service at or before accumulating the CSN in the following Table 1.

Table 1.—Part Number and Engine Applicability

Part No.	Engine applicability	Life limit CSN
808846 (old)	JT9D-3A, -7, -7A, -7AH, -7H, -7F, -7J, -20, -20J	15,000
811260 (new)	JT9D-3A, -7, -7A, -7AH, -7H, -7F, -7J, -20, -20J	15,000
809171 (old)	JT9D-3A, -7, -7A, -7AH, -7H, -7F, -20	15,000
811261 (new)	JT9D-3A, -7, -7A, -7AH, -7H, -7F, -20	15,000

(h) If the service life cannot be determined as specified in paragraph (f) of this AD, remove the 6th stage LPT air seal before accumulating 2,500 cycles-in-service after the effective date of this AD.

(i) After the effective date of this AD, do not install any 6th stage LPT air seal, P/N 808846, 809171, 811260, or 811261, that exceeds 15,000 CSN, or that was removed to comply with paragraph (h) of this AD because its service life could not be determined.

Alternative Methods of Compliance

(j) 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.

Material Incorporated by Reference

(k) You must use Pratt & Whitney Service Bulletin No. JT9D 6448, dated June 10, 2003, to perform the service life calculations required by this AD. Approval of incorporation by reference from the Office of the Federal Register is pending.

Related Information

(l) None.

Issued in Burlington, Massachusetts, on August 28, 2003.

Jay J. Pardee,

Manager, Engine and Propeller Directorate, Aircraft Certification Service.