[Federal Register Volume 60, Number 178 (Thursday, September 14, 1995)] [Rules and Regulations] [Pages 47685-47687] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 95-21960] ----------------------------------------------------------------------- DEPARTMENT OF TRANSPORTATION 14 CFR Part 39 [Docket No. 91-CE-22-AD; Amendment 39-9357; AD 95-18-10] Airworthiness Directives; de Havilland DHC-6 Series Airplanes AGENCY: Federal Aviation Administration, DOT. ACTION: Final rule. ----------------------------------------------------------------------- SUMMARY: This amendment supersedes Airworthiness Directive (AD) 81-10- 11, which currently requires repetitively inspecting the elevator root ribs for cracks on de Havilland DHC-6 series airplanes, and replacing any cracked part. The Federal Aviation Administration's policy on aging commuter-class aircraft is to eliminate, or, in certain instances, reduce the number of certain repetitive short-interval inspections when improved parts or modifications are available. This action requires modifying the elevator root rib as terminating action for the repetitive inspections currently required by AD 81-10-11. The actions specified by this AD are intended to prevent failure of the elevator root rib, which could result in loss of control of the airplane. DATES: Effective October 26, 1995. The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of October 26, 1995. ADDRESSES: Service information that applies to this AD may be obtained from de Havilland, Inc., 123 Garratt Boulevard, Downsview, Ontario, Canada, M3K1Y5. This information may also be examined at the Federal Aviation Administration (FAA), Central Region, Office of the Assistant Chief Counsel, Attention: Rules Docket 91-CE-22-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106; or at the Office of the Federal Register, 800 North Capitol Street NW., suite 700, Washington, DC. FOR FURTHER INFORMATION CONTACT: Jon Hjelm, Aerospace Engineer, FAA, New York Aircraft Certification Office, 10 Fifth Street, 3rd Floor, Valley Stream, New York 11581; telephone (516) 256-7523; facsimile (516) 568-2716. SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to de Havilland DHC-6 series airplanes that do not have Modification No. 6/1769 incorporated was published in the Federal Register on October 3, 1994 (59 FR 54412). The action proposed to supersede AD 81- 10-11 with a new AD that would (1) retain the current requirement of inspecting the elevator root rib for cracks, and replacing any cracked part; and (2) require modifying the elevator root rib (Modification 6/ 1769) as terminating action for the repetitive inspections. Accomplishment of the proposed actions would be in accordance with de Havilland Service Bulletin No. 6/399, Revision E, dated May 25, 1984. Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposed rule or the FAA's determination of the cost to the public. After careful review of all available information related to the subject presented above including the referenced service information, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed except for minor editorial corrections. The FAA has determined that these minor corrections will not change the meaning of the AD and will not add any additional burden upon the public than was already proposed. The FAA estimates that 169 airplanes in the U.S. registry will be affected by this AD, that it will take approximately 54 workhours per airplane to accomplish the required action, and that the average labor rate is approximately $60 an hour. Parts cost approximately $4,200 per airplane. Based on these figures, the total cost impact of this AD on U.S. operators is estimated to be $1,257,360. This figure is based on the assumption that none of the affected airplane owners/operators have incorporated Modification 6/1769. The intent of the FAA's aging commuter airplane program is to ensure safe operation of commuter-class airplanes that are in commercial service without adversely impacting private operators. Of the approximately 169 airplanes in the U.S. registry that will be affected by this AD, the FAA has determined that approximately 50 percent are operated in scheduled passenger service. A significant number of the remaining 50 percent are operated in other forms of air transportation such as air cargo and air taxi. The following paragraphs present cost scenarios for airplanes where no cracks were found and where cracks were found, utilizing an average remaining airplane life of 15 years and an average annual utilization rate of 1,600 hours time-in-service (TIS). De Havilland Models DHC-6- 100 and DHC-6-200 airplanes have probably already accumulated 15,000 hours TIS; therefore, those airplanes would have 100 hours TIS after the effective date of the AD to incorporate Modification 6/1769. Some Model DHC-6-300 airplanes have not yet accumulated 15,000 hours TIS. This analysis is based upon the assumption that those airplanes yet to accumulate 15,000 hours TIS have 10,000 hours TIS if operated in scheduled service and 5,000 hours TIS if operated in general aviation. A copy of the full Cost Analysis and Regulatory Flexibility Determination for this action may be examined at the FAA, Central Region, Office of the Assistant Chief Counsel, Attention: Rules Docket No. 91-CE-22-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri.No Cracks Scenario for Models DHC-6-100 and DHC-6-200: These airplanes will be inspected at 50 hours TIS after the effective date and modified within 100 hours TIS after the effective date. The incremental present value cost of this AD over that required by AD 81- 10-11 is $5,919 for an airplane utilized [[Page 47686]] in scheduled service, and $6,642 for an airplane utilized in general aviation. No Cracks Scenario for Model DHC-6-300 Airplanes: These airplanes will be inspected at 50 hours TIS after the effective date and thereafter at 600-hour TIS intervals until the elevator root rib is replaced upon the accumulation of 15,000 hours TIS. The incremental present value cost of this AD over that required by AD 81-10-11 is $4,962 for an airplane utilized in scheduled service, and $3,099 for an airplane utilized in general aviation. 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 will have a ``significant economic impact on a substantial number of small entities,'' and, in cases where they could, 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. A ``substantial number'' is defined as a number that is not less than 11 and that is more than one-third of the small entities subject to a rule, or any number of small entities judged to be substantial by the rulemaking official. A ``significant economic impact'' is defined by an annualized net compliance cost, adjusted for inflation, which is greater than a threshold cost level for defined entity types. FAA Order 2100.14A sets the size threshold for small entities operating aircraft for hire at 9 aircraft owned and the annualized cost thresholds, adjusted to 1994 dollars, at $69,000 for scheduled operators and $5,000 for unscheduled operators. Of the 169 U.S.-registered airplanes affected by this AD, six airplanes are owned by the federal government. Of the other 163 airplanes, one business owns 26 airplanes, two businesses own 9 airplanes each, one business owns 8 airplanes, one business owns 7 airplanes, one business owns 5 airplanes, four businesses own 3 airplanes each, sixteen businesses own 2 airplanes each, and fifty-five businesses own 1 airplane each. Because the FAA has no readily available means of obtaining data on the sizes of these entities, the economic analysis for this AD utilizes the worst case scenario using the lower annualized cost threshold of $5,000 for operators in unscheduled service instead of $69,000 for operators in scheduled service. With this in mind and based on the above ownership distribution, this AD could have a significant impact on a substantial number of small entities. Because of this, 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 not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 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 part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows: PART 39--AIRWORTHINESS DIRECTIVES 1. The authority citation for part 39 continues to read as follows: Authority: 49 USC 106(g), 40101, 40113, 44701. Sec. 39.13 [Amended] 2. Section 39.13 is amended by removing Airworthiness Directive (AD) 81-10-11, Amendment 39-4112, and adding a new AD to read as follows: 95-18-10 De Havilland: Amendment 39-9357; Docket No. 91-CE-22-AD. Supersedes AD 81-10-11, Amendment 39-4112. Applicability: Models DHC-6-1, DHC-6-100, DHC-6-200, and DHC-6- 300 airplanes (all serial numbers), certificated in any category, that do not have Modification No. 6/1769 incorporated. Note 1: This AD applies to each airplane identified in the preceding applicability revision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (e) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it. Compliance: Required as indicated in the body of the AD, unless already accomplished. To prevent failure of the elevator root rib, which could result in loss of control of the airplane, accomplish the following: (a) Within the next 50 hours time-in-service (TIS) after the effective date of this AD, unless already accomplished (compliance with AD 81-10-11), inspect the elevator root rib, part number (P/N) C6TE1022, for cracks in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of de Havilland Service Bulletin (SB) No. 6/ 399, Revision E, dated May 25, 1984. (1) If any crack is found, prior to further flight, accomplish one of the following: (i) Replace the cracked part with an airworthy part and reinspect thereafter at intervals not to exceed 600 hours TIS until the modification required in paragraph (b) of this AD is incorporated; or (ii) Incorporate Modification 6/1769 in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of de Havilland SB No. 6/399, Revision E, dated May 25, 1984. Note 2: Modification 6/1769 consists of pulling back the elevator skins, removing the torque tube assembly, replacing the root rib assembly and doubler, replacing the second outboard nose rib, installing a new intercostal, and reinstalling the torque tube assembly and new skin. (2) If no cracks are found, reinspect thereafter at intervals not to exceed 600 hours TIS until the modification required in paragraph (b) of this AD is incorporated. (b) Upon the accumulation of 15,000 hours TIS or within the next 100 hours TIS after the effective date of this AD, whichever occurs [[Page 47687]] later, unless already accomplished, incorporate Modification 6/1769 in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of de Havilland SB No. 6/399, Revision E, dated May 25, 1984. (c) Incorporating Modification 6/1769 as specified in paragraphs (a)(1)(ii) and (b) of this AD is considered terminating action for the inspection requirements of this AD. (d) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. (e) An alternative method of compliance or adjustment of the initial or repetitive compliance times that provides an equivalent level of safety may be approved by the Manager, New York Aircraft Certification Office (ACO), FAA, 10 Fifth Street, 3rd Floor, Valley Stream, New York 11581. The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, New York ACO. Note 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the New York ACO. (f) The inspections and modification required by this AD shall be done in accordance with de Havilland Service Bulletin No. 6/399, Revision E, dated May 25, 1984. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from de Havilland, Inc., 123 Garratt Boulevard, Downsview, Ontario M3K 1Y5 Canada. Copies may be inspected at the FAA, Central Region, Office of the Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at the Office of the Federal Register, 800 North Capitol Street NW., 7th Floor, suite 700, Washington, DC. (g) This amendment (39-9357) supersedes AD 81-10-11, Amendment 39-4112. (h) This amendment (39-9357) becomes effective on October 26, 1995. Issued in Kansas City, Missouri, on August 28, 1995. Henry A. Armstrong, Acting Manager, Small Airplane Directorate, Aircraft Certification Service. [FR Doc. 95-21960 Filed 9-13-95; 8:45 am] BILLING CODE 4910-13-U