A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 77-07-05, Amendment 39-2862 (42 FR 17868, April 4, 1977) and Amendment 39-2917 (42 FR 30604, June 16, 1977), which is applicable to Hiller Aircraft Corporation Model UH-12, UH-12A, UH-12B, UH-12C, UH-12D, UH-12E, CH-112, H-23A, H-23B, H-23C, H-23D, H-23F, HTE-1, HTE-2, and OH-23G helicopters, and UH-12D and UH-12E helicopters converted to turbine engine power in accordance with STC No.'s SH177WE and SH178WE, was published in the Federal Register on September 13, 1996 (61 FR 48441). That action proposed to require, within the next 100 hours time-in-service (TIS) after the effective date of this AD, unless accomplished within the last 100 hours TIS, and thereafter at intervals not to exceed 100 hours TIS from the date of the last inspection, or at the next annual inspection, whichever occurs first, an inspection of the blade spar tube and cuff for corrosion orcracks, or elongation, corrosion, burrs, pitting or fretting of the bolt holes, and repair, as necessary, in accordance with Hiller Aviation Service Bulletin No. 36-1, Revision 3, dated October 24, 1979.
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.
The commenter suggests several changes to the Hiller Aircraft Corporation service bulletin and the proposed rule. These include changes in the disassembly/reassembly techniques, such as warming of the cuff to facilitate blade removal, and replacement of certain lubrication and corrosion prevention materials. The manufacturer and the FAA have evaluated the suggestions to facilitate disassembly/reassembly, and the FAA has determined that while helpful, the changes are not necessary to accomplish the inspections of the AD. Further, the manufacturer reports no service experience that would indicate a needed change inlubrication or corrosion protection materials or techniques as suggested by the commenter. The suggested changes are not adopted.
The commenter also suggests two type design changes that are outside the scope of the proposal. The FAA will consider these suggested changes for future rulemaking action.
Finally, the commenter also cites a conflict between the mandatory replacement times (total service life) in the Hiller Inspection Guide and those proposed in the proposal. The conflict results because cuff mandatory replacement time, as specified in the Inspection Guide, depends on certain combinations of cuff, control blades, and main rotor blades. This dependency was not adequately considered in the proposal. Since the FAA did not intend to change these mandatory replacement times by the proposal, and since it is unnecessary to repeat Inspection Guide information in the AD, paragraphs (d)(1) and (d)(2) are removed from this final rule and paragraph (d)(3) becomes paragraph (d).
The FAA has determined that several blade spar tube and cuff part numbers were omitted from the proposal. The proposed rule's Applicability has been changed to specify that only helicopters having a blade spar tube, part numbers (P/N) 36003, 36006, 36129, 36129-25, 36203, 36203-15, 36203-21, or 36209-3, or cuff, P/N 36101-1, 36101-4, 36108, 36115-1, 36115-4, 36115-6, 36115-8, or 36124, installed, are affected.
After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes described previously. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.
The FAA estimates that 673 helicopters of U.S. registry will be affected by this AD, that it will take approximately 2 work hours per helicopter to accomplish the inspection, 1 work hour to accomplish the repair,and 8 work hours to accomplish the replacement, if necessary, and that the average labor rate is $60 per work hour. Required parts will cost approximately $1,000 per cuff, if replacement is necessary. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $121,140, assuming after inspection that repairs are necessary on all of the fleet, or $246,772, assuming inspection of all the fleet and replacement of a cuff in one-sixth of the fleet is necessary.
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) 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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."
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 39continues to read as follows:
Authority: 49 USC 106(g), 40113, 44701.
39.13 - [Amended]
2. Section 39.13 is amended by removing Amendment 39-2862 (42 FR 17868, April 4, 1977), and Amendment 39-2917 (42 FR 30604, June 16, 1977), and by adding a new airworthiness directive (AD), Amendment 39-10029, to read as follows: