2010-15370. Airworthiness Directives; Eurocopter France Model EC 155B, EC155B1, SA-360C, SA-365C, SA-365C1, SA-365C2, SA-365N, SA-365N1, AS-365N2, AS 365 N3, and SA-366G1 Helicopters

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes superseding an existing airworthiness directive (AD) for the specified Eurocopter France (Eurocopter) helicopters. That AD requires repetitively inspecting the main gearbox (MGB) planet gear carrier for a crack and replacing any MGB that has a cracked planet gear carrier before further flight. This action would require the same inspections required by the existing AD but would shorten the initial inspection interval. This proposal is prompted by the discovery of another crack in a MGB planet gear carrier and additional analysis that indicates that the initial inspection interval must be shortened. The actions specified by the proposed AD are intended to detect a crack in the web of the planet gear carrier, which could lead to a MGB seizure and subsequent loss of control of the helicopter.

DATES:

Comments must be received on or before August 27, 2010.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
• Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
• You may get the service information identified in this proposed AD from American Eurocopter Corporation, 2701 Forum Drive, Grand Prairie, TX 75053-4005, telephone [phone], fax [phone], or at http://www.eurocopter.com.

You may examine the comments to this proposed AD in the AD docket on the Internet at http://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT:

Gary Roach, Aviation Safety Engineer, Rotorcraft Directorate, FAA, 2601 Meacham Blvd., Fort Worth, Texas 76137, telephone [phone], fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the caption ADDRESSES. Include “Docket No. FAA-2010-0610; Directorate Identifier 2009-SW-47-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD because of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed rulemaking. Using the search function of the docket Web site, you can find and read the comments to any of our dockets, including the name of the individual who sent or signed the comment. You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78).

Examining the Docket

You may examine the docket that contains the proposed AD, any comments, and other information in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The street address for the Docket Operations office (telephone [phone]) is in the ADDRESSES section of this AD. Comments will be available in the AD docket shortly after receipt.

Discussion

On February 1, 2005, we issued AD 2005-03-09, Amendment 39-13965 (70 FR 7382, February 14, 2005), to require the following:

• For a MGB that has less than 250 hours time-in-service (TIS) since new or last overhaul, borescope inspecting or visually inspecting the web of the planet gear carrier for a crack. The inspections must be done on or before the MGB reaches 265 hours TIS and then at intervals not to exceed 50 hours TIS.
• For a MGB that has 250 or more hours TIS since new or since last overhaul, borescope inspecting or visually inspecting the web of the planet gear carrier for a crack. The inspections must be done within 15 hours TIS and then at intervals not to exceed 50 hours TIS.
• For any MGB that has a cracked planet gear carrier, replacing the MGB with an airworthy MGB before further flight.

That action was prompted by the discovery of cracks in the main gearbox during overhaul. The requirements of that AD are intended to detect a crack in the web of the planet gear carrier, which could lead to a MGB seizure and subsequent loss of control of the helicopter.

Since the issuance of AD 2005-03-09, an additional crack has been found 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 proposed AD would shorten the initial inspection from 265 hours TIS to 35 hours TIS. The recurring 50 hour-TIS inspections would remain the same.

The European Aviation 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 proposed AD would require inspecting the MGB planet gear carrier for a crack and replacing the MGB before further flight if a crack is found. The actions would be required to be accomplished by following specified portions of the EASBs described previously.

Differences Between This Proposed AD and the EASA AD

The MCAI references the service information rather than stating compliance times as we have done in this proposed AD. Unlike the EASBs, we have structured our compliance times based on a 250-hour TIS threshold. Also, the proposed AD does not require you to report cracks in the planet gear carrier to the manufacturer.

Costs of Compliance

We estimate that this AD will affect 145 helicopters of U.S. registry. We also estimate that it would take about 1 work-hour per helicopter for each borescope inspection and 12 work-hours for each visual inspection. Replacing the MGB, if necessary, would take about 16 work-hours. The average labor rate is $85 per work-hour. Required parts would cost about $66,780 per MGB. Based on these figures, we estimate the cost of this AD on U.S. operators would be $3,486,760, assuming that a borescope inspection would be done on the entire fleet 12 times a year, that no visual inspections would be done, and that 49 MGBs would be replaced.

Regulatory Findings

We have determined that this proposed AD would not have federalism implications under Executive Order 13132. Additionally, this proposed AD would 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 proposed 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 proposed 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
• Safety
• Incorporation by reference

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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.

§ 39.13

[Amended]

2. Section 39.13 is amended by removing Amendment 39-13965 (70 FR 7382, February 14, 2005), and adding the following new AD:

Eurocopter France: Docket No. FAA-2010-0610; Directorate Identifier 2009-SW-47-AD. Supersedes AD 2005-03-09; Docket No. FAA-2005-20294; Directorate Identifier 2004-SW-39-AD.

Applicability

Model EC 155B, EC155B1, SA-360C, SA-365C, SA-365C1, SA-365C2, SA-365N, SA-365N1, AS-365N2, AS 365 N3, and SA-366G1 helicopters, certificated in any category.

Compliance

Required as indicated.

For a main gearbox (MGB) that has:	Inspect:
(1) Less than 250 hours time-in-service (TIS) since new or last overhaul	On or before the MGB reaches 35 hours TIS, unless accomplished previously, and thereafter at intervals not to exceed 50 hours TIS.
(2) 250 or more hours TIS since new or last overhaul	Within 15 hours TIS, unless accomplished previously, and thereafter at intervals not to exceed 50 hours TIS.

To detect a crack in the web of the planet gear carrier, which could lead to a MGB seizure and subsequent loss of control of the helicopter, accomplish the following:

(a) Either borescope inspect the web of the MGB planet gear carrier for a crack in accordance with the Operational Procedure, paragraphs 2.B.2. through 2.B.2.a.1, of Eurocopter Emergency Alert Service Bulletin (EASB) No. 05A007, Revision 2; No. 05.00.48, Revision 3; No. 05.26, Revision 2; or No. 05.33, Revision 2; as applicable to your model helicopter, or visually inspect the MGB planet gear carrier in accordance with the Operational Procedure, paragraphs 2.B.3. through paragraph 2.B.3.a.1, of the EASB applicable to your model helicopter. Each EASB at the stated revision level is dated November 16, 2009.

(b) If a crack is found in the planet gear carrier, replace the MGB with an airworthy MGB before further flight.

(c) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Contact the Manager, Safety Management Group, FAA, ATTN: Gary Roach, Aviation Safety Engineer, Rotorcraft Directorate, FAA, 2601 Meacham Blvd., Fort Worth, Texas 76137, telephone [phone], fax [phone], for information about previously approved alternative methods of compliance.

(d) The Joint Aircraft System/Component (JASC) Code is 6320: Main Rotor Gearbox.

Note:

The subject of this AD is addressed in European Aviation Safety Agency AD No. 2007-0288-E, dated November 15, 2007.

Issued in Fort Worth, Texas, on June 16, 2010.

Gwendolynne O'Connell,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.