03-20573. Airworthiness Directives; Rolls-Royce Corporation (formerly Allison Engine Company) AE 3007A1, AE 3007A1/1, AE 3007A1/3, AE 3007A3, AE 3007A1E, and AE 3007A1P 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 Rolls-Royce Corporation (formerly Allison Engine Company) AE 3007A1, AE 3007A1/1, AE 3007A1/3, AE 3007A3, AE 3007A1E, and AE 3007A1P turbofan engines, with 1st to 2nd stage turbine spacers, part number (P/N) 23069627, 23070989, 23072849, or 23075364 installed. This proposed AD would reduce the life limit for 1st to 2nd stage turbine spacer, part number (P/N) 23072849, to a certain lower life limit, based on engine model. This proposed AD would also require a one-time fluorescent penetrant inspection (FPI) of 1st to 2nd stage turbine spacers P/Ns 23069627, 23070989, 23072849, and 23075364 before reaching the spacer life limit, within specified cycles-since-new (CSN), and would require replacement of the spacer if found cracked, or with bent or missing aft tangs. This proposed AD is prompted by a report that during a scheduled inspection, aft pilot tangs on a 1st to 2nd stage turbine spacer were found bent and cracked. The actions specified in this proposed AD are intended to prevent 1st to 2nd stage turbine spacer failure, leading to uncontained turbine failure, engine shutdown, and damage to the airplane.

DATES:

We must receive any comments on this proposed AD by October 14, 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-19-AD, 12 New England Executive Park, Burlington, MA 01803-5299.
• By fax: [phone].
• By e-mail: [e-mail].

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:

Michael Downs, Aerospace Engineer, Chicago Aircraft Certification Office, FAA, Small Airplane Directorate, 2300 East Devon Avenue, Des Plaines, IL 60018; 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-19-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 through a nonwritten communication, 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.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 been made aware that during a scheduled engine inspection, aft pilot tangs on a 1st to 2nd stage turbine spacer were found cracked and bent. The manufacturer has determined that the cause of the cracking and bending is due to a tight interference fit between the 2nd stage high pressure turbine wheel and the 1st to 2nd stage turbine spacer, and a fillet radius on the aft tangs, that is too small. The manufacturer is making design changes to decrease the interference fit of a replacement 1st to 2nd stage turbine spacer. The manufacturer has reduced the original life limit for spacer part number 23072849. The manufacturer is also requesting FPI of this spacer P/N 23072849 and three other related spacers P/Ns 23069627, 23070989, and 23075364. This action is considered interim and future AD action may be taken based on inspection results and replacement part availability.

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 reduce the 20,000 CSN life limit for the replacement 1st to 2nd stage turbine spacer, P/N 23072849, to 13,100 CSN for engine models AE 3007A1/1, AE 3007A1/3, AE 3007A1, and AE 3007A3, and to 12,900 CSN for engine models AE 3007A1E and AE 3007A1P. This proposed AD would also require a one-time FPI of 1st to 2nd stage turbine spacers P/Ns 23069627, 23070989, 23072849, and 23075364 before reaching the spacer life limit, within specified CSN, and would require replacement of spacers if found cracked, or with bent or missing aft tangs.

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 approximately 1,244 engines of the affected design in the worldwide fleet. We estimate that 850 engines installed on airplanes of U.S. registry would be affected by this proposed AD. We estimate the prorated replacement cost of a spacer for engine models AE 3007A1/1, AE 3007A1/3, AE 3007A1, and AE 3007A3 to be $13,755, and $13,545 for engine models AE 3007A1E and AE 3007A1P. We also estimate that approximately 45%, or 382, of the 850 domestic engines will require replacement spacers. We also estimate that it would take approximately 1 work hour per engine to perform the proposed inspection, and that the average labor rate is $60 per work hour. We also estimate that it would take approximately 18 work hours per engine to perform the proposed part replacement. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $5,649,780.

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-19-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:

Rolls-Royce Corporation: Docket No. 2003-NE-19-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by October 14, 2003.

Affected ADs

(b) None.

Applicability

(c) This AD is applicable to Rolls-Royce Corporation (formerly Allison Engine Company) AE 3007A1, AE 3007A1/1, AE 3007A1/3, AE 3007A3, AE 3007A1E, and AE 3007A1P turbofan engines, with 1st to 2nd stage turbine spacer part number (P/N) 23069627, 23070989, 23072849, or 23075364 installed. These engines are installed on, but not limited to, EMBRAER EMB-135 and EMB-145 series airplanes.

Unsafe Condition

(d) This AD was prompted by a report that during a scheduled inspection, aft pilot tangs were found bent and cracked on a 1st to 2nd stage turbine spacer. The actions specified in this AD are intended to prevent 1st to 2nd stage turbine spacer failure, leading to uncontained turbine failure, engine shutdown, and damage to 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.

1st to 2nd Stage Turbine Spacer Life Limits

(f) 1st to 2nd stage turbine spacer life limits are as follows:

(1) For P/N 23072849, the newly established life limit is:

(i) 13,100 cycles-since-new (CSN) for engine models AE 3007A1/1, AE 3007A1/3, AE 3007A1, AE 3007A3; and

(ii) 12,900 CSN for engine models AE 3007A1E and AE 3007A1P.

(2) For P/Ns 23069627, 23070989, and 23075364, the life limits are unchanged.

Inspection

(g) After the effective date of this AD, perform a one-time fluorescent penetrant inspection (FPI) of the 1st to 2nd stage turbine spacer P/Ns 23069627, 23070989, 23072849, and 23075364 and replace spacer if cracked or if aft pilot tangs are bent or missing, with a new or serviceable 1st to 2nd stage turbine spacer, using the following compliance criteria:

(1) For an engine inducted into the shop for any reason, if the spacer has accumulated 3,000 CSN or more.

(2) For installed engines, if the spacer has accumulated more than 9,300 CSN, inspect before accumulating an additional 500 cycles-in-service, or before accumulating 4,200 cycles-since-last FPI, whichever is more, but do not exceed the spacer life limit in paragraph (f) of this AD.

(3) For installed engines, if the spacer has accumulated 9,300 or less CSN, inspect before accumulating 9,800 CSN, or before accumulating 4,200 cycles-since-last FPI, whichever is more, but do not exceed the spacer life limit in paragraph (f) of this AD.

Alternative Methods of Compliance

(h) Alternative methods of compliance must be requested in accordance with 14 CFR part 39.19, and must be approved by the Manager, Chicago Aircraft Certification Office, FAA.

Related Information

(i) The subject of this AD is addressed in Rolls-Royce Corporation alert service bulletin No. AE 3007A-A-72-265, Revision 1, dated April 10, 2003.

Issued in Burlington, Massachusetts, on August 7, 2003.

Francis A. Favara,

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