A proposal to amend part 39 of the Federal Aviation Regulations to include an AD that would apply to certain Twin Commander 500, 600, and 700 series airplanes was published in the Federal Register on June 30, 1993 (58 FR 34955). The action proposed to supersede AD 65-06-01 with a new AD that would (1) retain the inspection and repair requirements of the spar caps required by AD 65-06-01; (2) incorporate the updated service information into the proposed AD; and (3) increase the effectivity of the current AD to include other airplane models of the Twin Commander 500, 600, and 700 series. The proposed inspections would be accomplished in accordance with Twin Commander SB No.90C, dated March 30, 1992, and Twin Commander Service Publications revision notice of SB No. 90C, Revision 1, dated June 5, 1992.
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the 10 commentsreceived.
Nine commenters concur with the proposal as written.
Twin Commander supports the proposal and makes recommendations. Twin Commander states that the Compliance section of the proposal contains the following: ". . . or 500 hours after the wing front lower spar cap was replaced in accordance with one of the three modifications referenced in paragraph (b) of this AD . . .", and points out that paragraph (b) of this AD only specifies two modifications and that the wording in the Compliance section of the proposal should be changed accordingly. The FAA concurs and has changed the proposed AD by inserting the words "in accordance with one of the two modifications" in place of "in accordance with one of the three modifications" under the Compliance section.
Twin Commander also states that the proposed AD should include the Model 680F(P) airplanes in the applicability to coincide with SB 90C. The FAA concurs that these airplanes should be included. Adding this airplane model to the applicability goes beyond the scope of what was originally proposed, and would obligate the FAA to issue a supplemental notice of proposed rulemaking (NPRM) to allow additional time for the public to comment. The FAA has determined that the additional comment time is unnecessary for the model airplanes included in the applicability of the proposed AD, and, after the proposed rule becomes final, the FAA will issue an NPRM to add the Model 680F(P) airplanes into the applicability of that AD. The proposed rule is unchanged as a result of this comment.
After careful review of all available information including the comments referenced above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed except for the minor wording change and other minor editorial corrections. The FAA has determined that these minor corrections will not change the meaning of the AD nor add any additional burden upon the public than wasalready proposed.
The FAA estimates that 1,303 airplanes in the U.S. registry will be affected by this AD, that it will take approximately 32 (average) workhours per airplane to accomplish the required action, and that the average labor rate is approximately $55 an hour. Parts are not required for 1,054 airplanes, and parts cost approximately $700 per airplane for 105 airplanes and $1,700 per airplane for 144 airplanes. Based on these figures, the total cost impact of the inspections specified in this AD on U.S. operators is estimated to be $2,611,580 (cost per airplane varies by model).
AD 65-06-01 currently requires the same actions as this AD on 1,025 of 1,303 airplanes. Of the remaining 307 airplanes affected by this AD, the FAA estimates that it will take approximately 18 workhours for 156 airplanes and 100 workhours for 151 airplanes, depending upon the particular model. Parts are not required for 156 airplanes and cost approximately $1,700 for 151 airplanes. Based on these figures, the cost impact of this AD upon U.S. operators not already affected by AD 65-06-01 is approximately $1,241,640 (cost per airplane varies by model).
In addition, if the required inspection reveals cracks in the spar cap, replacing the spar cap is required at a cost of approximately $100,000, parts and labor included. An airplane affected by this AD could have a compliance cost as low as approximately $990 (18 workhours) or $7,200 (100 workhours) if cracks were not found during the inspection, and as high as approximately $100,990 (inspection using 18 workhours + spar replacement) to $107,200 (inspection using 100 workhours + spar replacement) if the operator replaces the spar cap.
The FAA estimates that the airplanes affected by the required AD are utilized an average of approximately 200 hours time-in-service per year, or an average time-interval between the required inspections of 2.5 years.
Based on an expected average remaining operating life of 20 years per affected airplane, the annualized compliance cost would be:
If only repetitively inspecting the spar cap is necessary at 18 workhours: $456 annualized cost (using a 7 percent interest rate);
If only repetitively inspecting the spar is necessary at 100 workhours: $2,700 annualized cost (using a 7 percent interest rate); or
If replacing the spar cap is necessary: approximately $9,971 annualized cost (with 18 workhours for inspection and using a 7 percent interest rate) and $10,372 annualized cost (with 100 workhours for inspection and using a 7 percent interest rate) if the spar cap is replaced during the first inspection.
The required AD's from Dockets No. 92-CE-26-AD (for Model 500S), No. 92-CE-57-AD (for Models 500, 560A, 560E, 680, 680E, and 720), and No. 92-CE-58-AD (for Models 500S, 500U, 680FL, 680W, and 681), also affect certain airplanes included in this AD. The compliance costs of these AD's add to the cost discussed above. However, replacing the spar cap is only required once, so the $100,000 replacement cost, if required, would be a one-time action.
The Regulatory Flexibility Act of 1980 (RFA) was enacted by Congress to ensure that small entities are not unnecessarily or disproportionally burdened by government regulations. The RFA requires government agencies to determine whether rules would have a "significant economic impact on a substantial number of small entities," and, in cases where they would, conduct a Regulatory Flexibility Analysis in which alternatives to the rule are considered. FAA Order 2100.14A, Regulatory Flexibility Criteria and Guidance, outlines FAA procedures and criteria for complying with the RFA. Small entities are defined as small businesses and small not-for-profit organizations that are independently owned and operated or airports operated by small governmental jurisdictions.
The 307 U.S.-registered airplanes affected by this AD that are not already affected by AD 65-06-01 are ownedaccording to the following breakdown: 80 by individuals, 3 by U.S. government agencies, 9 by states or local governments, and 215 by other entities. Four entities own more than one of the affected airplanes that are not affected by AD 65-06-01: two own 2 each, and two own 5 each. Three entities own models that will be affected by this AD, as well as AD 65-06-01.
The FAA cannot determine the sizes of all the affected non-individual owner entities nor the relative significance of the costs estimated above. Because of these uncertainties, no cost thresholds for significant economic impact can be reasonably determined. The FAA solicited comments concerning the impact of the NPRM on owners of affected airplanes, and received no comments on this matter. Based on the possibility that this AD could have a significant impact on a substantial number of small entities, the FAA conducted a regulatory flexibility analysis. A copy of this analysis may be obtained by contacting the Rules Docket at the location provided under the caption "ADDRESSES".
The regulations adopted herein will not have substantial direct effects 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. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is significant under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979) because of substantial public interest; and, (3) if promulgated, may have a significant economic impact on a substantial number of small entities. The FAA has conducted an Initial Regulatory Flexibility Determination and Analysis and has considered alternatives to this action that could minimize the impact on small entities. A copy of this analysis may be obtained by contacting the Rules Docket at the location provided under the caption "ADDRESSES". After careful consideration, the FAA has determined that the required action is the best course to achieve the safety objective of returning the airplane to its original certification level of safety.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 14 CFR part 39 of the Federal Aviation Regulations as follows:
PART 39 - AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89.
Section 39.13 - [AMENDED]
2. Section 39.13 is amended by removing AD 65-06-01, Amendment 39-1053, and by adding the following new airworthiness directive to read as follows: