### Regulatory Flexibility Determination Airworthiness Directive

– Twin Commander Aircraft LLC Airplanes

The Regulatory Flexibility Act of 1980 (Public Law 96

- 354) (RFA) establishes “as a principle of regulatory issuance that agencies shall endeavor, consis tent with the objectives of the rule and of applicable statutes, to fit regulatory and informational requirements to the scale of the businesses, organizations, and governmental jurisd ictions subject to regulation.” To achieve this principle, agencies are required to solicit and consider flexible regulatory proposals and to explain the rationale for their actions to assure that such proposals are given serious consideration.” The RFA covers a wide

range of small entities, including small businesses, not

- f or
- profit organizations, and small governmental jurisdictions. Agencies must perform a review to determine whether a rule will have a significant economic impact on a substantial number of small entities. If the agency determines that it will, the agency must prepare a regulatory flexibility analysis as
described in the RFA.

A. Reason for Agency Action
We are adopting a new airworthiness directive (AD) for certain Twin Commander Aircraft LLC Models 690, 690A, and 690B airplanes. This AD requires inspectio n for cracking of the outer fuselage attachments, the lower wing main spar, the vertical channels, the upper picture window channels, aft cabin pressure web, external wing to fuselage fillets, and fasteners; repair or replacement of damaged parts as necess ary; and2 modification of the structure with reinforced parts . This AD was prompted by cracks found in the upper picture window frame channels, left

- and right

- hand wing main spar frame support channels, and aft pressure bulkhead web. This condition, if not corrected, could result in st ructural failure of the airplane

. We are issuing th e AD to correct the unsafe condition on these products.

B. Legal Basis and Objectives of the Final Rule
Title 49 of the United States Code specifies the FAA’s authority to iss ue 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 descr ibed 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 th e 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.

C. Recordkeeping and Other Compliance Requirements of the Rule Compliance Comp liance with the AD must occur within the times specified, unless already done.3 Inspection (1) Inspect the airplane structural components , at the compliance times specified in paragraphs (g)(1)( i) through (g)(1)(iv) of the AD following Part I of Twin Commander Aircraft LLC Service Bulletin 241, September 26, 2012: (i) For airplanes with 10,000 or more hours time

- in

- service (TIS), inspect within the next 30 days after the effective date of th e AD. (ii) For airplanes with 7,500 t hrough 9,999 hours TIS, inspect within the next 60 days after the effective date of th e AD. ( iii) For airplanes with 5,000 through 7,499 hours TIS, inspect within the next 6 months after the effective date of th e AD. (iv) Fo r airplanes with less than 5,000 hours TIS, inspect when the airplane accumulates a total of 5,000 hours TIS or within the next 12 months after the effective date of th e AD, whichever occurs later. Repair If any damage, cracks, and/or cracks that exceed th e allowable limits specified in the service bulletin are found during the inspection required in paragraph (g)(1) of th e AD, before further flight, repair or replace parts as necessary following Twin Commander Aircraft LLC Service Bulletin 241, dated, Sept ember 26, 2012. If Twin Commander Aircraft LLC Service Bulletin 241, dated, September 26, 2012, does not give procedures for repair of the damaged area, before furt her flight, you must contact Twin Commander Aircraft LLC to obtain repair instructions appr oved by the Seattle Aircraft Certification Office (ACO) specifically for compliance with this AD and i ncorporate those instructions

. You can find contact information for Twin Commander Aircraft LLC in paragraph (l)(2) of th e AD. Modification and Reassembly (1) Before further flight after completing the actions in paragraphs (g) and (h) of th e AD, modify and reassemble the airplane using the modification and reassembly4 procedures in Part II of Twin Commander Aircraft LLC Service Bulletin 241, dated, Septemb er 26, 2012. (2) Although Twin Commander Aircraft LLC Service Bulletin 241, dated September 26, 2012, states that at least one person on the modification team must have completed the Twin Commander Aircraft LLC approved training, the FAA does not require that a mechanic complete this specialized training to do the modification work required in th e AD. Regulations 14 CFR 65.81(a) and 14 CFR 65.81(b) provide criteria about qualifications of those performing maintenance; in this case, the requirements of th e AD.

D. Federal Rules that May Duplicate, Overlap, or Conflict with the Proposed Rule
There are no rules that duplicate, overlap or conflict with the Airworthiness Directive.

E. Description and estimation of the number of Small Entities Affected by Rule

Un der the RFA, the FAA must determine whether a proposed rule significantly affects a substantial number of small entities. This determination is typically based on small entity size and revenue thresholds that vary depending on the affected industry. 1

To determine the number of small entities affected by the airworthiness directive , we searched the FAA A ircraft R egistry database

. 2 The database provides ownership
information for 175 of the airplanes affected by the AD, and average airplane values for
these aircraft are available in the Aircraft Bluebook Price Digest

.

1 Thresholds are based on the North American Industry Classification System (NAICS) . The NAICS is the standard used by Federal statistical agencies in cl assifying business establishments for the purpose of collecting, analyzing, and publishing statistical data related to the U.S. business economy.5 The FAA aircraft registry categorizes owners of affected airplanes as individuals,

co
- owners, corporations, and governments. A review of the corporations shows that an overwhelming majority are privately held. In most cases, the information about the se corporations cannot be determined because financial and employment data for privately held entities is sparse. Nevertheless, the FAA believes the number of small business
entities affected by this AD is substantial.
T he serial numbers for the 175 affected airplanes that we have information on

was used to look up average retail values in the Aircraft Bluebook Price Digest
. 3 The “Digest” provides average retail values by model, year, and serial number. It is only a guide since the actual condition and upgrades to individual airplanes are not known. The
value range for the 175 affected airplanes is between $225,000 and $555,000 per airplane. The range is primarily due to age ( i.e., the older an airplane the lower its retail value versus a newer model of the same airplane). The total retail value of the affected airplanes is equal to the sum of the retail value for each individual airplane. This summation equals $78.9 million (or an aver age of about $451,000 per airplane)

. The economic impact on small entities due to the AD is significant. This
determination is based on the percentage of the cost of compliance per airplane ($58,090)

to the average retail value per airplane ($451,000) , which is estimated to be 12.9 percent.

Based on the discussion above , c omplying with th is AD is determined to be significant economic impact on a substantial number of small entities.

2 FAA Aircraft Registry Database by Make and Model of Aircraft as of June 2013

. These aircraft were manufactu red by Aero Commander and Rockwell. 3 Winter 2011 Edition.6 F. Alternatives Considered Given the immediate safety problem , the FAA had to act immediately which resulted in our rejection of extending compliance time. If an unsafe condition is not found in the inspection no repair expense will occur. 

### International Trade Impact Assessment The Trade Agreements Act of 1979 (P ublic Law 96

- 39), as amended by the Uruguay Round Agreements Act (Public Law 103

- 465), prohibits Federal agencies from establishing standards or engaging in related activities that create unnecessary obstacles to the foreign commerce of the United States. Pursuant to these Acts, the establishment of standards is not considered an unnecessary obstacle to the foreign commerce of the United States, so long as the standard has a legitimate domestic objective, such as the protection of safety, and does not oper ate in a manner that excludes imports that meet this objective. The statute also requires consideration of international standards and, where appropriate, that they be the basis for U.S. standards. The FAA has assessed the potential
effect of this final rule and determined that because it addresses an immediate safety issue this rule is not considered an unnecessary obstacle to the foreign commerce of the United
States

.

Unfunded Mandates Assessment

Title II of the Unfunded Mandates Reform Act of 1995 (Public Law 104

- 4) requires each Federal agency to prepare a written statement assessing the effects of any Federal mandate in a proposed or final agency rule that may result in an expenditure of7 $100 million or more (in 1995 dollars) in any one year by S tate, local, and tribal governments, in the aggregate, or by the private sector; such a mandate is deemed to be a "significant regulatory action." The FAA currently uses an inflation

- adjust ed value of $143.1 million in lieu of $100 million. This final ru le does not contain such a mandate; therefore, the requirements of Title II of the Act do not apply.