AD 2014-16-14

This AD is effective September 23, 2014.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of September 23, 2014.

For service information identified in this AD, 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 98057. For information on the availability of this material at the FAA, call 425-227-2112.

Marie Hogestad, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-6418; fax: 425-917-6590; email: marie.hogestad@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 737-600, -700, -700C, -800, and -900 series airplanes. The NPRM published in the Federal Register on March 3, 2014 (79 FR 11728). The NPRM was prompted by reports in which a single, undetected, erroneous radio altimeter output caused the autothrottle to enter landing flare retard mode prematurely on approach. The NPRM proposed to require removing certain autothrottle computers and installing a new or reworked autothrottle computer. We are issuing this AD to prevent a single, undetected, erroneous radio altimeter output from causing premature autothrottle landing flare retard and subsequent loss of automatic speed control, which could result in loss of control of the airplane.

We gave the public the opportunity to participate in developing this AD. The following presents the comments received on the NPRM (79 FR 11728, March 3, 2014) and the FAA's response to each comment.

Boeing and the National Transportation Safety Board (NTSB) concurred with the NPRM (79 FR 11728, March 3, 2014).

Aviation Partners Boeing stated that installation of winglets per Supplemental Type Certificate (STC) ST00830SE does not affect the accomplishment of the manufacturer's service instructions specified in the NPRM (79 FR 11728, March 3, 2014).

Kevin Lee, a private citizen, requested that we increase the cost estimate of the NPRM (79 FR 11728, March 3, 2014). The commenter stated that the cost will be significantly higher due to General Electric not providing a free-of-charge upgrade to the autothrottle computer despite this being a safety and reliability issue.

We disagree with increasing the cost estimate. The cost estimate does not include parts cost for the autothrottle computer because it is considered “Parts and Materials Supplied by the Operator” in Boeing Alert Service Bulletin 737-22A1215, dated November 22, 2013. The autothrottle computer software can be updated using a data loader on a bench with specific equipment that is unique to the GE autothrottle computer. However, since this autothrottle computer has been out of production for over ten years, it is unlikely that operators will have the capability to do the update themselves using a disc supplied by GE. Therefore, GE anticipates that the majority of operators will return their autothrottle computer to a GE service center for modification. As an alternative, operators may purchase the autothrottle computer from Boeing. Boeing Alert Service Bulletin 737-22A1215, dated November 22, 2013, does not give the cost and it is therefore not included in our estimate. Since there are multiple ways for operators to get an updated autothrottle computer, we have not included the cost of the autothrottle computer in our estimate. We also do not control warranty coverage. No change has been made to this final rule in this regard.

Kevin Lee requested that we delay issuance of the final rule, or extend the proposed 36-month compliance time specified in the NPRM (79 FR 11728, March 3, 2014). The commenter stated that Boeing has not incorporated the new GE autothrottle computer having part number (P/N) 760SUE2-5 into their Boeing 737 Illustrated Parts Catalog (IPC) or the Instructions for Continued Airworthiness documents.

We disagree with delaying issuance of this final rule. Paragraph 1.K. of Boeing Alert Service Bulletin 737-22A1215, dated November 22, 2013, identifies the Boeing 737 IPC as the only document affected by replacement of the autothrottle computer. The new autothrottle computer has been added to the IPC, therefore there is no need to delay issuance of the final rule.

We also disagree with extending the 36-month compliance time. In developing an appropriate compliance time for this action, we considered the urgency associated with the subject unsafe condition, the availability of required parts, and the practical aspect of accomplishing the required modification within a period of time that corresponds to the normal scheduled maintenance for most affected operators. According to the manufacturer, an ample number of required parts will be available to modify the U.S. fleet within the proposed compliance time. However, under the provisions of paragraph (i) of this final rule, 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 regard to either delaying the final rule or extending the 36-month compliance time.

We reviewed the relevant data, considered the comments 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 (79 FR 11728, March 3, 2014) for correcting the unsafe condition; and

• Do not add any additional burden upon the public than was already proposed in the NPRM (79 FR 11728, March 3, 2014).

We also determined that these changes will not increase the economic burden on any operator or increase the scope of this AD.

We estimate that this AD affects 497 airplanes of U.S. registry.

We estimate the following costs to comply with this AD:

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):