A proposal to amend 14 CFR part 39 by superseding AD 2005-03-09, Amendment 39-13965 (70 FR 7382, February 14, 2005), for the specified Eurocopter France (Eurocopter) model helicopters was published in the Federal Register on June 28, 2010 (75 FR 36581). The action proposed to require shortening the initial inspection required by AD 2005-03-09 from 265 hours time-in-service (TIS) to 35 hours TIS and retaining the 50-hour TIS recurring inspections. That proposal was prompted by the finding of an additional crack in the MGB planet gear carrier of a Eurocopter Model EC 155 helicopter. That crack was caused by a progressive fatigue failure caused by scoring in the blend radius between the pin and the web. An additional analysis indicates that the initial inspection must be shortened. Therefore, this AD shortens the initial inspection from 265 hours time-in-service (TIS) to 35 hours TIS. The recurring 50 hour-TIS inspections would remain the same.
The EuropeanAviation Safety Agency (EASA), which is the Technical Agent for France, has issued EASA Emergency Airworthiness Directive No. 2007-0288-E, dated November 15, 2007. EASA states that cracks were discovered in the web of the MGB planet gear carrier. "The two affected MGB units had been removed for overhaul/repair, subsequent to the detection of metal chips at the magnetic plugs.'' Investigation of the first case showed a failure of the head of a screw that secures the sun gear bearing. The screw head was caught by the planet gear/fixed ring gear/sun gear drive train. The second case was discovered by the manufacturer and did not seem to be associated with any other failure. You may obtain further information by examining the MCAI and any related service information in the AD docket.
Related Service Information
Eurocopter France has issued the following Emergency Alert Service Bulletins:
No. 05A007, Revision 2, for the Model EC155 helicopters;
No. 05.00.48, Revision 3,for the Model AS365 helicopters;
No. 05.26, Revision 2, for the Model SA360 and SA365 helicopters; and
No. 05.33, Revision 2, for the SA366 helicopters.
Each Emergency Alert Service Bulletin (EASB) at the stated revision level is dated November 16, 2009 and describes the discovery of a progressive fatigue failure of the planet gear carrier. The EASBs specify inspecting the MGB planet gear carrier for a crack and removing the MGB and contacting the manufacturer before the next flight if a crack is found.
FAA's Evaluation and Unsafe Condition Determination
These products have been approved by the aviation authority of France and are approved for operation in the United States. Pursuant to our bilateral agreement with France, EASA, their technical representative, has notified us of the unsafe condition described in the MCAI AD. We are proposing this AD because we evaluated all information provided by EASA and determined the unsafe condition exists and is likely to exist or develop on other products of these same type designs. This AD requires inspecting the MGB planet gear carrier for a crack and replacing the MGB before further flight if a crack is found. The actions must be accomplished by following the specified portions of the EASBs described previously.
Differences Between This Proposed AD and the MCAI AD
The MCAI AD references the service information rather than stating compliance times as we have done in this AD. Unlike the MCAI AD, we have structured our compliance times based on a 250-hour TIS threshold. Also, this AD does not require you to report cracks in the planet gear carrier to the manufacturer.
Comments
Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposal or the FAA's determination of the cost to the public. The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.
Costs of Compliance
We estimate that this AD will affect 145 helicopters of U.S. registry. We also estimate that it will take about 1 work-hour per helicopter for each borescope inspection and 12 work-hours for each visual inspection. Replacing the MGB, if necessary, will take about 16 work-hours. The average labor rate is $85 per work-hour. Required parts will cost about $66,780 per MGB. Based on these figures, we estimate the cost of this AD on U.S. operators is $3,486,760, assuming that a borescope inspection is done on the entire fleet 12 times a year, that no visual inspections are done, and that 49 MGBs are replaced.
Regulatory Findings
We have determined that 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 the regulation:
1. Is not a "significant regulatory action'' under Executive Order 12866;
2. Is not a "significant rule'' under the 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.
We prepared an economic evaluation of the estimated costs to comply with this AD. See the AD docket to examine the economic evaluation.
Authority for This Rulemaking
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.
We are 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.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:
PART 39--AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by removing Amendment 39-13965 (70 FR 7382, February 14, 2005), and byadding a new airworthiness directive (AD), Amendment 39-16455, to read as follows: