2010-13314. Airworthiness Directives; Pratt & Whitney PW4000 Series 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 PW4000 series turbofan engines. This proposed AD would require a one-time visual inspection of the No. 3 bearing oil pressure tube, part number (P/N) 51J041-01, P/N 50J604-01, or P/N 50J924-01. Tubes that are found cracked or repaired would be required to be removed from service. This proposed AD would also prohibit repaired tubes from being installed. This proposed AD results from one report of a repaired No. 3 bearing oil tube that caused an engine in-flight shutdown, seven reports of repaired No. 3 bearing oil pressure tubes found cracked that led to unscheduled engine removals, and one report of a test cell event from a repaired tube that cracked. We are proposing this AD to prevent cracking of No. 3 bearing oil pressure tubes which could result in internal oil fire, failure of the high-pressure turbine (HPT) disks, uncontained engine failure, and damage to the airplane.

DATES:

We must receive any comments on this proposed AD by August 2, 2010.

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: [phone].

FOR FURTHER INFORMATION CONTACT:

James Gray, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: [e-mail]; telephone [phone]; fax [phone].

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-2010-0384; Directorate Identifier 2010-NE-18-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 [phone]) is the same as the Mail address provided in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

Discussion

In August 2009, we received a report of a Pratt & Whitney PW4000 series turbofan engine failure during flight. Investigation revealed that the engine had an internal oil fire caused by a cracked No. 3 bearing oil pressure tube, and that the tube was previously weld-repaired. That fire led to failure of the high-pressure compressor rear shaft and damage to the HPT stages 1-2 air seal and HPT disks. Since 2007, we have also received seven other reports of repaired No. 3 bearing oil pressure tubes cracking, resulting in unscheduled engine removals. The operational interaction of the tube and diffuser case can cause wear. A weld-repaired tube can exhibit decreased capability and be more likely to crack than a tube that has not been repaired. Because of the type of environment these tubes operate in, tubes that are cracked or repaired, or if suspected that the tube was repaired, would be required to be removed from service. Operating the engines with cracked No. 3 bearing oil pressure tubes, if not corrected, could result in internal oil fire, failure of the HPT disks, uncontained engine failure, and damage to the airplane.

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:

• A one-time visual inspection of the No. 3 bearing oil pressure tube, P/N 51J041-01, P/N 50J604-01, or P/N 50J924-01; and
• Removal from service if found cracked or repaired, or if suspected that the tube was repaired; and
• A prohibition on installing repaired tubes.

Costs of Compliance

We estimate that this proposed AD would affect 973 PW4000 series turbofan engines installed on airplanes of U.S. registry. We also estimate that it would take about 10 minutes per engine to perform the proposed one-time visual inspection when the tube has been removed, and that the average labor rate is $85 per work-hour. Required parts would cost about $9,154 per engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $8,923,383.

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.

§ 39.13

[Amended]

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

Pratt & Whitney: Docket No. FAA-2010-0384; Directorate Identifier 2010-NE-18-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by August 2, 2010.

Affected ADs

(b) None.

Applicability

(c) This AD applies to the following Pratt & Whitney turbofan engines, with No. 3 bearing oil pressure tube, part number (P/N) 51J041-01, P/N 50J604-01, or P/N 50J924-01, installed:

PW4000-94″ Engines

(1) PW4000-94″ engines affected are PW4050, PW4052, PW4056, PW4060, PW4060A, PW4060C, PW4062, PW4062A, PW4152, PW4156, PW4156A, PW4158, PW4160, PW4460, PW4462, and PW4650, including models with any dash number suffix.

PW4000-100″ Engines

(2) PW4000-100″ engines affected are PW4164, PW4168, PW4168A, PW4164C, PW4164C/B, PW4170, PW4168A-1D, PW4168-1D, PW4164-1D, PW4164C-1D, and PW4164C/B-1D, including models with any dash number suffix.

PW4000-112″ Engines

(3) PW4000-112″ engines affected are PW4074, PW4074D, PW4077, PW4077D, PW4084, PW4084D, PW4090, PW4090-3, PW4090D, and PW4098, including models with any dash number suffix.

(4) These engines are installed on, but not limited to, Airbus A300, A310, and A330 series, Boeing MD-11, 747, 767, and 777 series, airplanes.

Unsafe Condition

(d) This AD results from one report of a repaired No. 3 bearing oil pressure tube that cracked and caused an engine in-flight shutdown, one report of a test cell event, and eight reports since 2007, of repaired No. 3 bearing oil pressure tubes found cracked that led to unscheduled engine removals. We are issuing this AD to prevent cracking of No. 3 bearing oil pressure tubes which could result in internal oil fire, failure of the high-pressure turbine disks, uncontained engine failure, and damage to the airplane.

Compliance

(e) You are responsible for having the actions required by this AD performed the next time the No. 3 bearing oil pressure tube is removed from the engine after the effective date of this AD, unless the actions have already been done.

One-Time Visual Inspection of the No. 3 Bearing Oil Pressure Tube

(f) Perform a one-time visual inspection of the exterior of the No. 3 bearing oil pressure tube for cracks and evidence of being repaired.

(1) Remove the tube from service if any cracks are found.

(2) Remove the tube from service if found repaired, or if suspected that the tube was repaired.

(g) After the effective date of this AD, do not install any repaired No. 3 bearing oil pressure tube into any engine.

(h) Guidance on the No. 3 bearing oil pressure tube visual inspection can be found in:

(1) Pratt & Whitney Clean, Inspect, Repair Manual PN 51A357, 72-41-20 for PW4000-94″ and PW4000-100″ series engines; or

(2) Pratt & Whitney Clean, Inspect, Repair Manual PN 51A750, 72-41-20 for PW4000-112″ series engines.

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) Contact James Gray, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: [e-mail]; telephone [phone]; fax [phone], for more information about this AD.

(k) Contact Pratt & Whitney, 400 Main St., East Hartford, CT 06108, telephone [phone]; fax [phone], for a copy of the repair manuals referenced in paragraphs (h)(1) and (h)(2) of this AD.

Issued in Burlington, Massachusetts, on May 27, 2010.

Peter A. White,

Assistant Manager, Engine and Propeller Directorate, Aircraft Certification Service.