AD 2009-23-07

We are adopting a new airworthiness directive (AD) for the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) originated 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:

During 2008, two cases of main hydraulic accumulator failure were reported, one of which was caused by corrosion. Investigation has shown that a severe failure can occur to any of the four hydraulic accumulators which are installed in the hydraulic compartment. Either one of the two end parts on the accumulator may depart from the pressure vessel due to corrosion. This condition, if not corrected, is likely to degrade the functionality of the hydraulic system, possibly resulting in degradation or total loss of control of the landing gear, flap actuation and brakes. A severe failure during flight may even result in debris penetrating and exiting the fuselage outer skin. When such a failure occurs while the aeroplane is on the ground, as in the two reported cases, this may cause severe damage to the fuselage and result in injuries to persons nearby.

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We are issuing this AD to require actions to correct the unsafe condition on these products.

Final rule.

2009-23-07 Saab AB, Saab Aerosystems: Amendment 39-16079. Docket No. FAA-2009-0134; Directorate Identifier 2008-NM-162-AD.

Effective Date

(a) This airworthiness directive (AD) becomes effective December 14, 2009.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Saab AB, Saab Aerosystems Model SAAB 340A (SAAB/SF340A) and SAAB 340B airplanes, all serial numbers, certificated in any category; on which hydraulic accumulators with part number (P/N) 08 8423 001 1 or P/N 08 8423 030 1 are installed, except accumulators with serial numbers listed in paragraph 3.B. of Saab Service Bulletin 340-29-023, Revision 01, dated April 3, 2009.

Subject

(d) Air Transport Association (ATA) of America Code 29: Hydraulic power.

Reason

(e) The mandatory continuing airworthiness information (MCAI) states:

During 2008, two cases of main hydraulic accumulator failure were reported, one of which was caused by corrosion. Investigation has shown that asevere failure can occur to any of the four hydraulic accumulators which are installed in the hydraulic compartment. Either one of the two end parts on the accumulator may depart from the pressure vessel due to corrosion. This condition, if not corrected, is likely to degrade the functionality of the hydraulic system, possibly resulting in degradation or total loss of control of the landing gear, flap actuation and brakes. A severe failure during flight may even result in debris penetrating and exiting the fuselage outer skin. When such a failure occurs while the aeroplane is on the ground, as in the two reported cases, this may cause severe damage to the fuselage and result in injuries to persons nearby.

Since AD 2008-0146 was issued, one more case of main hydraulic accumulator failure has been reported, which occurred in flight during final approach. The aeroplane was able to land safely and there were no injuries reported on the aeroplane or on the ground.

To address and correct this unsafe condition, a modified hydraulic accumulator has been developed, which is sealed between the barrel and the screw cap and between the screw cap and the end cap.

For the reasons described above, this EASA AD requires the replacement of the affected hydraulic accumulators P/N (part number) 08 8423 001 1 and P/N 08 8423 030 1, as identified in Saab SB (Service Bulletin) 340-29-023, with a modified hydraulic accumulator.

This AD is revised to indicate that the accomplishment of SAAB SB 340-29-024 is another acceptable method to correct the unsafe condition.

Actions and Compliance

(f) Unless already done, replace the hydraulic accumulator at the applicable time specified in paragraph (f)(1) or (f)(2) of this AD in accordance with the instructions of Saab Service Bulletin 340- 29-023 or 340-29-024, both Revision 01, both dated April 3, 2009, as applicable.

(1) For airplanes on which the manufacturing date of the hydraulic accumulator is June 2000 orearlier: Replace the accumulator with a new or modified accumulator within 12 months after the effective date of this AD.

(2) For airplanes on which the manufacturing date of the accumulator is July 2000 or later: Replace the accumulator with a new or modified accumulator within 10 years after the manufacturing date or within 12 months after the effective date of this AD, whichever occurs later.

(3) As of 12 months after the effective date of this AD, no person may install a hydraulic accumulator, P/N 08 8423 001 1 or P/N 08 8423 030 1 on any airplane, except accumulators with serial numbers listed in paragraph 3.B. of Saab Service Bulletin 340-29- 023, Revision 01, dated April 3, 2009.

(4) Actions done before the effective date of this AD in accordance with Saab Service Bulletin 340-29-023, dated June 10, 2008, are acceptable for compliance with the corresponding requirements of this AD.

FAA AD Differences

Note 1: This AD differs from the MCAI and/or service information as follows: Where the MCAI includes a compliance time of "24 months,'' we have determined that a compliance time of "within 12 months after the effective date of the AD'' is appropriate. The manufacturer and EASA agree with this reduction in compliance time.

Other FAA AD Provisions

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

(1) Alternative Methods of Compliance (AMOCs): The Manager, International Branch, ANM-116, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Shahram Daneshmandi, Aerospace Engineer, International Branch, ANM-116, Transport Airplane Directorate, FAA, 1601 Lind Avenue, SW., Renton, Washington 98057- 3356; telephone (425) 227-1112; fax (425) 227-1149. Before using any approved AMOC on any airplane to which the AMOC applies, notify your principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office.

(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 MCAI European Aviation Safety Agency Airworthiness Directive 2008-0146R1, dated April 16, 2009; and Saab Service Bulletins 340-29-023 and 340-29-024, both Revision 01, both dated April 3, 2009; for related information.

Material Incorporated byReference

(i) You must use Saab Service Bulletin 340-29-023, Revision 01, dated April 3, 2009; or Saab Service Bulletin 340-29-024, Revision 01, dated April 3, 2009; as applicable; to do the actions required by this AD, unless the AD specifies otherwise.

(1) The Director of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) For service information identified in this AD, contact Saab Aircraft AB, SAAB Aerosystems, SE-581 88, Link[ouml]ping, Sweden; telephone +46 13 18 5591; fax +46 13 18 4874; e-mail saab2000.techsupport@saabgroup.com; Internet http:// www.saabgroup.com.

(3) You may review copies of the service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221 or 425-227-1152.

(4) You may also review copies of the service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ ibr_locations.html.

Discussion

We issued a supplemental notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to the specified products. That supplemental NPRM was published in the Federal Register on August 12, 2009 (74 FR 40527). That supplemental NPRM proposed to correct an unsafe condition for the specified products. The MCAI states:

During 2008, two cases of main hydraulic accumulator failure were reported, one of which was caused by corrosion. Investigation has shown that a severe failure can occur to any of the four hydraulic accumulators which are installed in the hydraulic compartment. Either one of the two end parts on the accumulator may depart from the pressure vessel due to corrosion. This condition, if not corrected, is likely to degrade the functionality of the hydraulic system, possibly resulting in degradation or total loss of control of the landing gear, flap actuation and brakes. A severe failure during flight may even result in debris penetrating and exiting the fuselage outer skin. When such a failure occurs while the aeroplane is on the ground, as in the two reported cases, this may cause severe damage to the fuselage and result in injuries to persons nearby.

Since [EASA] AD 2008-0146 was issued, one more case of main hydraulic accumulator failure has been reported, which occurred in flight during final approach. The aeroplane was able to land safely and there were no injuries reported on the aeroplane or on the ground.

To address and correct this unsafe condition, a modified hydraulic accumulator has been developed, which is sealed between the barrel and the screw cap and between the screw cap and the end cap.

For the reasons described above, this EASA AD requires the replacement of the affected hydraulic accumulators P/N (part number) 08 8423 001 1 and P/N 08 8423 030 1, as identified in Saab SB (Service Bulletin) 340-29-023, with a modified hydraulic accumulator.This AD is revised to indicate that the accomplishment of SAAB SB 340-29-024 is another acceptable method to correct the unsafe condition.

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

Comments

We gave the public the opportunity to participate in developing this AD. We received no comments on the supplemental NPRM or on the determination of the cost to the public.

Conclusion

We reviewed the available data and determined that air safety and the public interest require adopting the AD as proposed.

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 required different actions in this AD from those in the MCAI in order to follow our FAA policies. Any such differences are highlighted in a NOTE within the AD.

Costs of Compliance

We estimate that this AD will affect 111 products of U.S. registry. We also estimate that it takes 8 work-hours per product to comply with the basic requirements of this AD. The average labor rate is $80 per work-hour. Required parts will cost $8,800 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 AD on U.S. operators to be $1,047,840, or $9,440 or 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 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 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.

Examining the AD Docket

You may examine the AD docket on the Internet at http:// www.regulations.gov; or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains the NPRM, the regulatory evaluation, any comments received, and other information. The streetaddress for the Docket Operations office (telephone (800) 647-5527) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

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