AD 2007-03-14

Superseded

Hydro-mechanical metering unit (HMU)

Key Information
2007-03-14
Superseded
February 20, 2007
January 29, 2007
FAA-2007-27009
39-14925
Applicability
["Engine"]
Not specified
Turbomeca S.A.
Arriel 2B1
Summary

We are adopting a new airworthiness directive (AD) for the products listed above. This 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:

This AD is prompted by several reported cases of rupture of the (hydro-mechanical metering unit (HMU)) constant delta pressure valve diaphragm on Arriel 2B1 engines, due to the wear of the delta P diaphragm fabric. Rupture can result in the loss of the automatic control mode of the helicopter, accompanied with a deterioration of the behavior of the auxiliary back-up mode (emergency mode).

The loss of automatic control mode coupled with the deteriorated performance of the backup mode can lead to the inability to continue safe flight, forced autorotation landing, or an accident. This AD requires actions that are intended to address the unsafe condition described in the MCAI.

Action Required

Final rule; request for comments.

Regulatory Text

2007-03-14 Turbomeca: Amendment 39-14925; Docket No. FAA-2007-27009; Directorate Identifier 2007-NE-02-AD.

Effective Date

(a) This airworthiness directive (AD) becomes effective February 20, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Turbomeca Arriel 2B1 turboshaft engines. These engines are installed on, but not limited to Eurocopter AS 350 B3 and EC 130 B4 helicopters.

Reason

(d) European Aviation Safety Agency (EASA) AD No. 2007-0006, dated January 9, 2007, states:

This AD is prompted by several reported cases of rupture of the (hydro-mechanical metering unit (HMU)) constant delta pressure valve diaphragm on Arriel 2B1 engines, due to the wear of the delta P diaphragm fabric. Rupture can result in the loss of the automatic control mode of the helicopter, accompanied with a deterioration of the behavior of the auxiliary back-up mode (emergency mode).

The loss of automatic control mode coupled with the deterioratedperformance of the backup mode can lead to the inability to continue safe flight, forced autorotation landing, or an accident.

Actions and Compliance

(e) Unless already done, do the following actions.

(1) Replace the HMU with a serviceable HMU before the HMU accumulates 2,000 hours-since-new, since-last-overhaul, or since- incorporation of Turbomeca Service Bulletin (SB) No. 292 73 2105; or within 30 days after the effective date of this AD, whichever occurs later.

(2) Thereafter, replace HMUs with a serviceable HMU at every 2,000 hours-since-new, since-last-overhaul, or since-incorporation of Turbomeca SB No. 292 73 2105, whichever occurs later.

(3) For the purposes of this AD, a serviceable HMU is an HMU fitted with a new constant delta P diaphragm in accordance with Turbomeca Service Bulletin No. 292 73 2818, dated October 18, 2006.

FAA AD Differences

(f) None.

Other FAA AD Provisions

(g) The following provisions also apply to this AD:(1) Alternative Methods of Compliance (AMOCs): The Manager, Engine 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: For any reporting requirement in this AD, under the provisions of the Paperwork Reduction Act, the Office of Management and Budget (OMB) has approved the information collection requirements and has assigned OMB Control Number 2120- 0056.

Related Information

(h) Refer to EASA Airworthiness Directive 2007-0006, dated January 9, 2007, and Turbomeca Mandatory Service BulletinNo. 292 73 2818, dated October 18, 2006, for related information.

(i) Contact Christopher Spinney, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; telephone (781) 238- 7175, fax (781) 238-7199; e-mail: christopher.spinney@faa.gov for more information about this AD.

Material Incorporated by Reference

(j) None.

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

Discussion

The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued Airworthiness Directive No. 2007-0006, dated January 9, 2007 (referred to after this as "the MCAI''), to correct an unsafe condition for the specified products. The MCAI states that:

This AD is prompted by several reported cases of rupture of the (hydro-mechanical metering unit (HMU)) constant delta pressure valve diaphragm on Arriel 2B1 engines, due to the wear of the delta P diaphragm fabric. Rupture can result in the loss of the automatic control mode of the helicopter, accompanied with a deterioration of the behavior of the auxiliary back-up mode (emergency mode).

The loss of automatic control mode coupled with the deteriorated performance of the backup mode can lead to the inability to continue safe flight, forced autorotation landing, or an accident. You may obtain further information by examining the MCAI in the AD docket.

Relevant Service Information

Turbomeca has issued Mandatory Service Bulletin No. 292 73 2818, dated October 18, 2006. The actionsdescribed in this service information are intended to correct the unsafe condition identified in the MCAI.

FAA's Determination and Requirements of This 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 issuing this AD because we evaluated all the 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 the 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 required 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 AD. These requirements take precedence over the actions copied from the MCAI.

FAA's Determination of the Effective Date

An unsafe condition exists that requires the immediate adoption of this AD. The FAA has found that the risk to the flying public justifies waiving notice and comment prior to adoption of this rule because of the high risk to engines that could experience a ruptured delta P diaphragm with HMUs that have accumulated over 2,000 operating hours. Therefore, we determined that notice and opportunity for public comment before issuing this AD are impracticable and that good cause exists for making this amendment effective in fewer than 30 days.

Comments Invited

This AD is a final rule that involves requirements affecting flight safety, and we did not precede it by notice and opportunity for public comment. We invite you to send any written relevant data, views, or arguments about this AD. Send your comments to an address listed under the ADDRESSES section. Include "Docket No. FAA-2007-27009; Directorate Identifier 2007-NE-02-AD'' at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this AD. We will consider all comments received by the closing date and may amend this AD because of 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 AD.

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 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 thenational 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 AD:

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 AD and placed it in the AD docket.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, 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. The FAA amends Sec. 39.13 by adding the following new AD:

AD Assistant

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Related ADs
2007-19-09 Replaced by the above
Contact Information

Christopher Spinney, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; telephone (781) 238-7175, fax (781) 238-7199; e-mail: christopher.spinney@faa.gov.

References
Federal Register: February 2, 2007 (Volume 72, Number 22)
--- - Part 39
Page 4948-4950
FAA Documents