E7-19684. Airworthiness Directives; Honeywell International Inc. ATF3-6 and ATF3-6A 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 Honeywell International Inc. ATF3-6 and ATF3-6A series turbofan engines equipped with a certain part number (P/N) low pressure compressor (LPC) aft shaft. This proposed AD would require removing from service those LPC aft shafts and installing a serviceable LPC aft shaft. This proposed AD results from reports of eight LPC aft shafts found cracked during fluorescent penetrant inspection (FPI). We are proposing this AD to prevent uncoupling and overspeed of the low pressure turbine, which could result in uncontained engine failure and damage to the airplane.

DATES:

We must receive any comments on this proposed AD by December 4, 2007.

ADDRESSES:

Use one of the following addresses to comment on this proposed AD.

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the online 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].

You can get the service information identified in this proposed AD from Honeywell International Inc., 111 S. 34th St., Phoenix, AZ 85034-2802; Web site: http://portal.honeywell.com/​wps/​portal/​aero;​; telephone [phone].

FOR FURTHER INFORMATION CONTACT:

Joseph Costa, Aerospace Engineer, Los Angeles Aircraft Certification Office, FAA, Transport Airplane Directorate, 3960 Paramount Blvd., Lakewood, CA 90712-4137; 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-2007-29092; Directorate Identifier 2007-NE-30-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. Anyone is able to search the electronic form of all comments received into any of our dockets by the name of the individual submitting the comment (or signing the comment, if submitted 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

During routine fluorescent penetrant inspection of P/N 3002070-1 LPC aft shafts, eight LPC aft shafts were found with cracks in the root radii of the curvic teeth. Five of eight cracked aft shafts were found to have fillet root radii of the curvic teeth below the manufacturing minimum limit. We have determined that curvic teeth machined to a small root radii increases local stresses and contributes to cracking. This condition, if not corrected, could result in uncoupling and overspeed of the low pressure turbine, uncontained engine failure, and damage to the airplane.

Relevant Service Information

We have reviewed and approved the technical contents of Honeywell International Inc. Service Bulletin (SB) No. ATF3-72-6240, Revision 1, dated May 14, 2007, that describes procedures for removing P/N 3002070-1 LPC aft shafts from service and installing a serviceable LPC aft shaft.

Differences Between the Proposed AD and the Manufacturer's Service Information

The compliance schedule in this proposed AD differs from the SB compliance schedule by improving format, by removing the hourly and calendar “at access” compliance time requirements, and by relaxing the compliance schedule.

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 removing LPC aft shafts, P/N 3002070-1 from service and installing a serviceable LPC aft shaft. The proposed AD would require you to use the service information described previously to perform these actions.

Costs of Compliance

We estimate that this proposed AD would affect 32 ATF3-6 and ATF3-6A series turbofan engines installed on airplanes of U.S. registry. We also estimate that it would take about 40 work-hours per engine to perform the proposed actions if unscheduled, 20 work-hours per engine if during scheduled major periodic inspection (MPI), and 1 work-hour per engine during scheduled core zone inspection (CZI). We estimate that 4 engines would be unscheduled, 14 engines would be scheduled at MPI, and 14 engines would be scheduled at CZI. The average labor rate is $80 per work-hour. Required parts would cost about $15,000 per engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $516,320.

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:

Honeywell International Inc. (formerly AlliedSignal Inc. and Garrett Turbine Engine Co.): Docket No. FAA-2007-29092; Directorate Identifier 2007-NE-30-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by December 4, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Honeywell International Inc. ATF3-6-4C, ATF3-6A-3C, and ATF3-6A-4C turbofan engines equipped with part number (P/N) 3002070-1 low pressure compressor (LPC) aft shaft. These engines are installed on, but not limited to, Dassault Aviation Fan Jet Falcon Series G (Falcon 20G/HU25), and Dassault Aviation Mystere-Falcon 200 airplanes.

Unsafe Condition

(d) This AD results from reports of eight LPC aft shafts found cracked during fluorescent penetrant inspection (FPI). We are issuing this AD to prevent uncoupling and overspeed of the low pressure turbine, which could result in uncontained engine failure and damage to the airplane.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified in Table 1 and Table 2 of this AD, unless the actions have already been done.

Table 1.—ATF3-6A-4C Turbofan Engines, LPC Aft Shaft Replacement Compliance Schedule

For ATF3-6A-4C turbofan engines, if the cycles-since-new (CSN) on the effective date of this AD are:	Then replace the LPC aft shaft:
(1) 6,500 or more CSN	Within an additional 100 cycles-in-service (CIS).
(2) 5,000 to 6,499 CSN	Within an additional 800 CIS, but not more than 6,600 CSN, whichever occurs first.
(3) 4,000 to 4,999 CSN	Within an additional 1,500 CIS, but not more than 5,800 CSN, whichever occurs first.
(4) Fewer than 4,000 CSN	Within an additional 2,000 CIS, but not more than 5,500 CSN, whichever occurs first.

Table 2.—ATF3-6-4C and ATF3-6A-3C Turbofan Engines, LPC Aft Shaft Replacement Compliance Schedule

For ATF3-6-4C and ATF3-6A-3C turbofan engines, if the CSN on the effective date of this AD are:	Then replace the LPC aft shaft:
(1) 4,400 or more CSN	Within an additional 100 CIS.
(2) 3,600 to 4,399 CSN	Within an additional 500 CIS, but not more than 4,500 CSN, whichever occurs first.
(3) 3,300 to 3,599 CSN	Within an additional 700 CIS, but not more than 4,100 CSN, whichever occurs first.
(4) Fewer than 3,300 CSN	Within an additional 1,000 CIS, but not more than 4,000 CSN, whichever occurs first.

LPC Aft Shaft Replacement

(f) Using the compliance schedule in Table 1 or Table 2 of this AD as applicable, remove the LPC aft shaft P/N 3002070-1, from service, and install a serviceable LPC aft shaft.

Definition

(g) For the purpose of this AD, a serviceable LPC aft shaft is an aft shaft with a P/N not referenced in this AD.

Alternative Methods of Compliance

(h) The Manager, Los Angeles Aircraft 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

(i) Honeywell International Inc. Service Bulletin No. ATF3-72-6240, Revision 1, dated May 14, 2007, pertains to the subject of this AD.

(j) Contact Joseph Costa, Aerospace Engineer, Los Angeles Aircraft Certification Office, FAA, Transport Airplane Directorate, 3960 Paramount Blvd., Lakewood, CA 90712-4137; e-mail: [e-mail]; telephone: [phone]; fax: [phone].

Issued in Burlington, Massachusetts, on October 1, 2007.

Peter A. White,

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