AD 2020-25-01

This AD is effective January 11, 2021.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of January 11, 2021.

For service information identified in this final rule, contact Textron Aviation Inc., P.O. Box 7706, Wichita, KS 67277; phone: 316-517-5800; internet: https://txtav.com/. You may view this service information at the FAA, Airworthiness Products Section, Operational Safety Branch, 901 Locust St., Kansas City, MO 64106. For information on the availability of this material at the FAA, call 816-329-4148. It is also available on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-0718.

Brian C. Adamson, Aviation Safety Engineer, Wichita ACO Branch, AIR-7K3, FAA, 1801 Airport Rd, Wichita, KS 67209; phone: 316-946-4193; fax: 316-946-4107; email: brian.adamson@faa.gov or Wichita-COS@faa.gov.

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain Textron (type certificate previously held by Beechcraft Corporation) Models F90, 65-90, 65-A90, B90, C90, H90 (T-44A), E90, 65-A90-1 (JU-21A, U-21A, RU-21A, RU-21D, U-21G, RU-21H), 65-A90-2 (RU-21B), 65-A90-3 (RU-21C), 65-A90-4 (RU-21E, RU-21H), 99, 99A, 99A (FACH), A99, A99A, B99, C99, 100, A100 (U-21F), and B100 airplanes. The NPRM published in the Federal Register on July 29, 2020 (85 FR 45545).

The NPRM was prompted by Textron receiving reports of fatigue cracks in the lower forward wing fitting on two airplanes. Investigation revealed that installing washer P/N 90-380058-1 on the wing bolt will cause a premature torque indication. This washer may have been installed as part of kit 101-4024-3 on Models F90, 65-90, 65-A90, B90, C90, H90 (T-44A), E90, 65-A90-1 (JU-21A, U-21A, RU-21A, RU-21D, U-21G, RU-21H), 65-A90-2 (RU-21B), 65-A90-3 (RU-21C), 65-A90-4 (RU-21E, RU-21H), 99, 99A, 99A (FACH), A99, A99A, B99, C99, 100, A100 (U-21F), and B100 airplanes, or as part of kit 90-4077-1 on Models 65-90, 65-A90, 65-A90-1 (JU-21A, U-21A, RU-21A, RU-21D, U-21G, RU-21H), 65-A90-2 (RU-21B), 65-A90-3 (RU-21C), 65-A90-4 (RU-21E, RU-21H), B90, C90, and E90 airplanes. Under-torque of the wing bolt causes a reduced clamping force that changes the load path reacted by the RH and LH lower forward wing fitting.

In the NPRM, the FAA proposed to require a one-time inspection for the presence of washer P/N 90-380058-1 on the LH and RH lower forward wing bolt and, if applicable, removing washer P/N 90-380058-1, inspecting the wing fitting, bolt, and nut, replacing the wing fitting if it is cracked, and replacing the washer with washer P/N 90-380019-1. This condition, if not addressed, could result in fatigue cracks that lead to failure of the forward lower wing fitting, wing separation, and loss of airplane control.

The FAA received one comment from an individual commenter. The following presents the comment received on the NPRM and the FAA's response to the comment.

An individual commenter requested that the AD identify the applicable airplanes by serial number. The commenter stated that on the Beech Model C90A serial number LJ‐1450 airplane, the lower front wing connections are designed as shear fittings with shear bolts, and therefore the washers are not affected. The FAA disagrees. The AD, as proposed, clearly lists the applicable airplane models and serial numbers. The FAA responded to the commenter by email and advised that the AD, as proposed, would not apply to the Model C90A. A copy of the comment and the FAA's response is in the AD docket.

The FAA reviewed the relevant data, considered the comment received, and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these products.

The FAA reviewed Beechcraft Mandatory Service Letter MTL-57-01, Revision 1, dated September 19, 2018. The service information contains procedures for a one-time inspection for the presence of washer P/N 90-380058-1 on the LH and RH lower forward wing bolt and, if applicable, removing washer P/N 90-380058-1; inspecting the wing fitting, bolt, and nut; replacing the wing fitting if it is cracked; and replacing the washer with washer P/N 90-380019-1. 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.

The service information specifies inspecting within 200 flight hours or 12 months, whichever occurs earlier. This AD would require inspecting within the next 200 flight hours or 12 months, whichever occurs later.

The service information applies to Models A100A and A100C airplanes, and to Model F90 with S/N LA-1. This AD would not apply to these airplanes because they do not have an FAA type certificate.

This AD would apply to military Models T-44A, JU-21A, RU-21A, RU-21B, RU-21C, RU-21D, RU-21E, RU-21H, U-21A, U-21F, U-21G, and FACH airplanes, because these models have a civil counterpart that is subject to the unsafe condition. The service information does not apply to all of these military models.

The FAA estimates that this AD will affect 1,319 airplanes of U.S. registry.

The FAA estimates the following costs to comply with this AD:

The FAA estimates the following costs to do any necessary replacements that would be required based on the results of the inspection. The FAA has no way of determining the number of airplanes that might need these replacements:

The FAA has included all known costs in this cost estimate. According to the manufacturer, however, some of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected operators.

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.

The FAA is 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) Will not affect intrastate aviation in Alaska, and

(3) 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: