E6-21487. Airworthiness Directives; Microturbo Saphir 20 Models 095 Auxiliary Power Units (APU)

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) issued by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

It has been reported that with the existing configuration, a certain failure could cause overspeed of the gas generator rotor resulting in uncontained burst of the turbine liberating high-energy fragments.

The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.

DATES:

We must receive comments on this proposed AD by January 17, 2007.

ADDRESSES:

You may send comments by any of the following methods:

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Fax: [phone].
• Mail: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590-0001.
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
• Federal eRulemaking Portal: http://www.regulations.gov. Follow the instructions for submitting comments.

Examining the AD Docket

You may examine the AD docket on the Internet at http://dms.dot.gov;​; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (telephone [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Tracy Murphy, Aerospace Engineer, Boston Aircraft Certification Office, FAA, Engine and Propeller Directorate; 12 New England Executive Park, Burlington, MA 01803; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Streamlined Issuance of AD

The FAA is implementing a new process for streamlining the issuance of ADs related to MCAI. This streamlined process will allow us to adopt MCAI safety requirements in a more efficient manner and will reduce safety risks to the public. This process continues to follow all FAA AD issuance processes to meet legal, economic, Administrative Procedure Act, and Federal Register requirements. We also continue to meet our technical decision-making responsibilities to identify and correct unsafe conditions on U.S.-certificated products.

This proposed AD references the MCAI and related service information that we considered in forming the engineering basis to correct the unsafe condition. The proposed AD contains text copied from the MCAI and for this reason might not follow our plain language principles.

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 ADDRESSES section. Include “Docket No. FAA-2006-24846; Directorate Identifier 2006-NE-21-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD based on those comments.

We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD.

Discussion

The Direction Generale De l'Aviation Civile (DGAC), which is the airworthiness authority for France, has issued Airworthiness Directive F-2005-146, dated August 17, 2005 (Euoropean Aviation Safety Agency Reference No. 2005-6137, dated August 9, 2005) (referred to after this as “the MCAI”), to correct an unsafe condition for the specified products. The MCAI states:

It has been reported that with the existing configuration, a certain failure could cause overspeed of the gas generator rotor resulting in uncontained burst of the turbine liberating high-energy fragments. The occurrence that the high-energy fragments would be uncontained is considered a potentially dangerous situation which requires imperative corrective action. The purpose of the modification, which has been made mandatory, is to limit gas generator speed during an acceleration towards overspeed by installation of a modified Electronic Control Unit (ECU) and Drain Valve. In addition, the modification also renders the exhaust gas temperature (EGT) control function compliant with the certificated specifications. In operation, if EGT exceeds the certificated limit value, turbine blade shedding could occur.

You may obtain further information by examining the MCAI in the AD docket.

Relevant Service Information

Microturbo has issued Alert Service Bulletin No. 095-49A11, Edition 2, dated October 7, 2005. The actions described in this service information are intended to correct the unsafe condition identified in the MCAI.

FAA's Determination and Requirements of This Proposed AD

This product has been approved by the aviation authority of another country, and is approved for operation in the United States. Pursuant to our bilateral agreement with this State of Design Authority, they have notified us of the unsafe condition described in the MCAI and service information referenced above. We are proposing this AD because we evaluated all information provided by the State of Design Authority and determined the unsafe condition exists and is likely to exist or develop on other products of the same type design.

Differences Between This AD and the MCAI or Service Information

We have reviewed the MCAI and related service information and, in general, agree with their substance. But we might have found it necessary to use different words from those in the MCAI to ensure the AD is clear for U.S. operators and is enforceable. In making these changes, we do not intend to differ substantively from the information provided in the MCAI and related service information.

We might also have proposed different actions in this AD from those in the MCAI in order to follow FAA policies. Any such differences are described in a separate paragraph of the proposed AD. These requirements, if ultimately adopted, will take precedence over the actions copied from the MCAI.

Costs of Compliance

Based on the service information, we estimate that this proposed AD would affect about 3 products of U.S. registry. We also estimate that it would take about 10 work-hours per product to comply with this proposed AD. The average labor rate is $80 per work-hour. Required parts would cost about $1,000 per product. Where the service information lists required parts costs that are covered under warranty, we have assumed that there will be no charge for these costs. As we do not control warranty coverage for affected parties, some parties may incur costs higher than estimated here. Based on these figures, we estimate the cost of the proposed AD on U.S. operators to be $5,400 or $1,800 per product.

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.

Regulatory Findings

We determined that this proposed AD would not have federalism implications under Executive Order 13132. 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 this 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 a regulatory evaluation of the estimated costs to comply with this proposed AD and placed it in the AD docket.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

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. The FAA amends § 39.13 by adding the following new AD:

2006-XX-XX Microturbo: Docket No. FAA-2006-24846; Directorate Identifier 2006-NE-21-AD.

Comments Due Date

(a) We must receive comments by January 17, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Microturbo Saphir 20 Models 095 Auxiliary Power Units (APU) installed on, but not limited to, Eurocopter AS 332C, AS 332L, AS 332L1, and AS 332L2 helicopters.

Reason

(d) Direction Generale De l'Aviation Civile Airworthiness Directive F-2005-146, dated August 17, 2005, states:

It has been reported that with the existing configuration, a certain failure could cause overspeed of the gas generator rotor resulting in uncontained burst of the turbine liberating high-energy fragments. The occurrence that the high-energy fragments would be uncontained is considered a potentially dangerous situation which requires imperative corrective action. The purpose of the modification, which has been made mandatory, is to limit gas generator speed during an acceleration towards overspeed by installation of a modified Electronic Control Unit (ECU) and Drain Valve. In addition, the modification also renders the exhaust gas temperature (EGT) control function compliant with the certificated specifications. In operation, if EGT exceeds the certificated limit value, turbine blade shedding could occur.

Actions and Compliance

(e) Unless already done, do the following actions except as stated in paragraph (f) below.

(1) Within 60 days after the effective date of this AD, replace the existing ECU and drain valve.

(2) Follow paragraph 2. of Accomplishment Instructions of Microturbo Alert Service Bulletin (ASB) No. 095-49A11, Edition 2, dated October 7, 2005, to do these actions.

FAA AD Differences

(f) This AD differs from the mandatory continuing airworthiness information (MCAI) and/ or service information as follows:

(1) The MCAI issued by an airworthiness authority of another country refers to Microturbo ASB No. 095-49A11, dated July 27, 2005.

(2) This AD refers to Edition 2 of that ASB, dated October 7, 2005, which contains revised torque values.

Other FAA AD Provisions

(g) The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs): The Manager, Boston Aircraft Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19.

(2) Airworthy Product: For any requirement in this AD to obtain corrective actions from a manufacturer or other source, use these actions if they are FAA-approved. Corrective actions are considered FAA-approved if they are approved by the State of Design Authority (or their delegated agent). You are required to assure the product is airworthy before it is returned to service.

(3) Reporting Requirements: None.

Related Information

(h) For service information identified in this AD, contact Microturbo SA; Technical Publications Department; 8 Chemin du pont de Rupe, BP 62089; 31019 Toulouse Cedex 2, France; telephone [phone]; fax [phone].

(i) France AD No. F-2005-146, dated August 17, 2005, also pertains to the subject of this AD.

(j) Contact Tracy Murphy, Aerospace Engineer, Boston Aircraft Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; telephone [phone]; fax [phone], for more information about this AD.

Issued in Burlington, Massachusetts, on December 12, 2006.

Peter A. White,

Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service.