AD 2016-10-09

This AD is effective June 24, 2016.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of June 24, 2016.

For service information identified in this final rule, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P.O. Box 3707, MC 2H-65, Seattle, WA 98124-2207; telephone: 206-544-5000, extension 1; fax: 206-766-5680; Internet https://www.myboeingfleet.com. You may view this referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221. It is also available on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2015-6548.

Allen Rauschendorfer, Aerospace Engineer, Airframe Branch, ANM-120S, Seattle Aircraft Certification Office, FAA, 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-6487; fax: 425-917-6590; email: allen.rauschendorfer@faa.gov.

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain The Boeing Company Model 787-8 and 787-9 airplanes equipped with General Electric engines. The NPRM published in the Federal Register on December 11, 2015 (80 FR 76878) (“the NPRM”). The NPRM was prompted by reports of cracking in barrel nuts on a forward engine mount of Model 747-8 airplanes, which shares a similar design to the forward engine mount of Model 787-8 and 787-9 airplanes. The NPRM proposed to require, for certain airplanes, replacement of the four barrel nuts of the forward engine mount on each engine. For certain other airplanes, the NPRM proposed to require an inspection to determine if any forward engine mount barrel nut having a certain part number is installed; and related investigative and corrective actions if necessary. We are issuing this AD to detect and correct cracking of the forward engine mount barrel nuts. Such cracking could result in reduced load capacity of the forward engine mount and could result in separation of an engine from the airplane and consequent loss of control of the airplane.

We gave the public the opportunity to participate in developing this AD. The following presents the comment received on the NPRM and the FAA's response to the comment.

United Airlines requested that the compliance time in the NPRM for Group 1 airplanes be changed from 2 years to “at next engine change.” United considered the proposed compliance time to be “expedited” because it took Boeing 7 months to publish the service information operators would be required to use to comply with the requirements in the NPRM, and it took the FAA 6 months to publish the NPRM. The commenter reasoned that since it took over 1 year from the time a solution for the unsafe condition was identified to the publication of the NPRM, the timeline for completing the corrective action is not critical and could be accomplished at the next scheduled engine change. United Airlines explained that allowing operators to replace the forward barrel nuts at the next engine change would reduce the cost of compliance to zero and would not add additional burden to operators.

We do not agree with the commenter's request. In developing an appropriate compliance time for this action we considered not only the degree of urgency associated with addressing the subject unsafe condition, but the manufacturer's recommendation for an appropriate compliance time, the time required for the rulemaking process, and the practical aspect of doing the required replacement within an interval of time that corresponds to the typical scheduled maintenance for the majority of affected operators. However, under the provisions of paragraph (j) of this AD, we will consider requests for approval of an extension of the compliance time if sufficient data are submitted to substantiate that the new compliance time would provide an acceptable level of safety. We have not changed the AD in this regard.

We reviewed the relevant data, considered the comment received, and determined that air safety and the public interest require adopting this AD as proposed, except for minor editorial changes. 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 Boeing Service Bulletin B787-81205-SB710026-00, Issue 001, dated June 10, 2015. The service information describes procedures for replacing the forward engine mount barrel nuts with new, improved barrel nuts; doing an inspection to determine if barrel nuts having a certain part number are installed on the forward engine mount; and doing related investigative and corrective actions. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

We estimate that this AD affects 36 airplanes of U.S. registry.

We estimate the following costs to comply with this AD:

We estimate the following costs to do any related investigative actions required based on the results of the inspection. We have no way of determining the number of aircraft that might need these actions:

We have received no definitive data that will enable us to provide cost estimates for the on-condition corrective actions specified in this AD.

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 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, 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):