AD 2017-20-01

This AD is effective November 2, 2017.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of November 2, 2017.

For service information identified in this final rule, contact Honeywell International Inc., 111 S. 34th Street, Phoenix, AZ 85034-2802; phone: 800-601-3099; Internet: https://myaerospace.honeywell.com/wps/portal. You may view this service information at the FAA, Engine and Propeller Standards Branch, 1200 District Avenue, Burlington, MA 01803. For information on the availability of this material at the FAA, call (781) 238-7125. It is also available on the internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2016-9451.

Joseph Costa, Aerospace Engineer, Los Angeles ACO Branch, FAA, 3960 Paramount Blvd., Lakewood, CA 90712-4137; phone: 562-627-5246; fax: 562-627-5210; email: joseph.costa@faa.gov.

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to all Honeywell TFE731-20 and TFE731-40 turbofan engines. The NPRM published in the Federal Register on March 7, 2017 (82 FR 12755). The NPRM was prompted by two fan disks found with a manufacturing-caused flaw. The NPRM proposed to require removing the affected fan disks, performing a one-time inspection, and replacing fan disks that fail inspection. We are issuing this AD to prevent uncontained failure of the fan disks, damage to the engine, and damage to the airplane.

We gave the public the opportunity to participate in developing this final rule. We have considered the comment received.

We received a comment regarding Honeywell as a company that was not relevant to this AD. No further discussion is required.

Based on further review, we made the following changes to this AD.

We corrected the cost per product estimate under “On-condition costs” in the Costs of Compliance section of the NPRM from $300,510 to $50,085 in this AD. The cost per product in the NPRM incorrectly estimated the cost for six engines rather than for one engine. On further review, we also redefined the work hours needed to install the new or reworked fan disk. The 8 work hours to inspect the fan disk were listed as a separate item in the NPRM but, in this final rule, we added these work hours to the estimated cost of installing the reworked or new fan disk. The overall estimated cost of this work per engine remains the same.

We corrected the product identification from “Honeywell International Inc. (Type Certificate previously held by AlliedSignal Inc., Garrett Engine Division; Garrett Turbine Engine Company; and AiResearch Manufacturing Company of Arizona)” to “Honeywell International Inc. (Type Certificate previously held by AlliedSignal Inc.).”

We removed paragraph (g)(4) of the NPRM which required inspection of the removed fan disks in accordance with paragraph 3.D.(2) in the Accomplishment Instructions of Honeywell SB TFE731-72-5256, Revision 0, dated October 7, 2016. Although fan disks may be returned to Honeywell for inspection and rework to become eligible for installation, that is not a requirement of this AD.

We revised the definition of “parts eligible for installation” in paragraph (g) of this AD to read: “For the purposes of this AD, parts eligible for installation are: (i) Fan disks not listed in the Accomplishment Instructions, Table 9, in Honeywell SB TFE731-72-5256, Revision 0, dated October 7, 2016; or (ii) fan disks listed in Table 9 that have been inspected, reworked, and marked with “T43374” adjacent to the P/N or S/N. Guidance on returning affected parts to Honeywell for inspection and rework is found in the Accomplishment Instructions, paragraph 3.D., of Honeywell SB TFE731-72-5256.” This definition clarifies that fan disks with a P/N not affected by this AD, as well as parts that have been reworked and remarked, are eligible for installation.

We reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this final rule as proposed for minor editorial changes and the additional changes explained above. We have determined that these minor changes:

• Are consistent with the intent that was proposed in the NPRM for correcting the unsafe condition; and

• Do not add any additional burden upon the public than was already proposed in the NPRM.

We reviewed Honeywell Service Bulletin (SB) TFE731-72-5256, Revision 0, dated October 7, 2016. The SB identifies affected fan disks by serial number and describes procedures for removing, inspecting, and replacing the fan disks. This service information is available by the means identified in the ADDRESSES section.

We estimate that this AD affects 61 engines installed on airplanes of U.S. registry.

We estimate the following costs to comply with this AD:

We estimate the following costs to do any necessary disk replacements that would be required based on the results of the required inspection. We estimate that 6 engines will need this replacement:

According to the manufacturer, some of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected individuals. We do not control warranty coverage for affected individuals. As a result, we have included all costs in our cost estimate.

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.

This AD is issued in accordance with authority delegated by the Executive Director, Aircraft Certification Service, as authorized by FAA Order 8000.51C. In accordance with that order, issuance of ADs is normally a function of the Compliance and Airworthiness Division, but during this transition period, the Executive Director has delegated the authority to issue ADs applicable to engines, propellers, and appliances to the Manager, Engine and Propeller Standards Branch, Policy and Innovation Division.

This AD will not have federalism implications under Executive Order 13132. This AD will 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 this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Is not a “significant rule” under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979),

(3) Will not affect intrastate aviation in Alaska to the extent that it justifies making a regulatory distinction, and

(4) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

1. The authority citation for part 39 continues to read as follows:

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