E9-19261. Airworthiness Directives; Saab AB, Saab Aerosystems Model SAAB 340A (SAAB/SF340A) and SAAB 340B Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.

SUMMARY:

We are revising an earlier NPRM for the products listed above. This action revises the earlier NPRM by expanding the scope. This proposed 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.

* * * * *

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 September 8, 2009.

ADDRESSES:

You may send comments by any of the following methods:

• 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 W12-40, 1200 New Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this proposed AD, contact Saab Aircraft AB, SAAB Aerosystems, SE-581 88, Linköping, Sweden; telephone [phone]; fax [phone]; e-mail [e-mail]; Internet http://www.saabgroup.com. You may review copies of the referenced 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.

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 this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Shahram Daneshmandi, Aerospace Engineer, International Branch, ANM-116, Transport Airplane Directorate, FAA, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; 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 ADDRESSES section. Include “Docket No. FAA-2009-0134; Directorate Identifier 2008-NM-162-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://www.regulations.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

We proposed to amend 14 CFR part 39 with an earlier NPRM for the specified products, which was published in the Federal Register on February 18, 2009 (74 FR 7568). That earlier NPRM proposed to require actions intended to address the unsafe condition for the products listed above.

Since that NPRM was issued, there was another report of main hydraulic accumulator failure, which occurred during final approach. The airplane was able to land safely, and there were no injuries reported. We have determined that it is necessary to reduce the compliance time specified in the NPRM for replacing the hydraulic accumulator from 24 to 12 months.

The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued EASA Airworthiness Directive 2008-0146R1, dated April 16, 2009 (referred to after this as “the MCAI”), to correct an unsafe condition for the specified products. The revised 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.

Relevant Service Information

Saab has issued Service Bulletins 340-29-023 and 340-29-024, both Revision 01, both dated April 3, 2009. The actions described in this service information are intended to correct the unsafe condition identified in the MCAI.

Comments

We have considered the following comments received on the earlier NPRM.

Request To Reduce Compliance Time

Tactair Fluid Controls Inc. recommends that we reduce the compliance time specified in the NPRM for replacing the hydraulic accumulator from 24 to 12 months. Tactair states that the 24-month compliance time is too long given the age of the fleet of potentially affected airplanes. Tactair adds that shortening the compliance time to 12 months would provide an additional margin of safety.

We agree that the compliance time for replacing the hydraulic accumulator should be reduced to 12 months because of the recent incident of another failure of the hydraulic accumulator. We have determined that a compliance time of within 12 months after the effective date of the AD is appropriate and will ensure an acceptable level of safety. The manufacturer and EASA agree with this reduction in compliance time. We have changed paragraphs (f)(1), (f)(2), and (f)(3) of this AD accordingly.

Request To Expand Applicability

Tactair asks that the applicability specified in the NPRM be expanded to add Model SAAB 2000 airplanes. Tactair states that Model SAAB 2000 airplanes contain hydraulic accumulators with the same part numbers specified in the applicability of the NPRM.

We acknowledge the commenter's concern; however, we do not agree that Model SAAB 2000 airplanes should be added to this supplemental NPRM. EASA has determined that hydraulic accumulators with the same part numbers could be installed on Model SAAB 2000 airplanes; however, there have been no incidents on that model, and we consider the fleet safety risk to be lower for that model. The manufacturer has confirmed that service information with replacement procedures for Model SAAB 2000 airplanes will not be issued for several months. We will consider additional rulemaking once service information for the Model SAAB 2000 airplanes is developed and available. To delay issuing this supplemental NPRM would be inappropriate, since we have identified recent incidents on the affected models and have determined that the replacements must be done to ensure continued safety.

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 the State of Design Authority, we have been notified of the unsafe condition described in the MCAI and service information referenced above. We are proposing this AD because we evaluated all pertinent information and determined an unsafe condition exists and is likely to exist or develop on other products of the same type design.

Certain changes described above expand the scope of the earlier NPRM. As a result, we have determined that it is necessary to reopen the comment period to provide additional opportunity for the public to comment on this proposed AD.

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 highlighted in a NOTE within the proposed AD.

Costs of Compliance

Based on the service information, we estimate that this proposed AD would affect 111 products of U.S. registry. We also estimate that it would take 8 work-hours per product to comply with the basic requirements of this proposed AD. The average labor rate is $80 per work-hour. Required parts would 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 proposed 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 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
• Incorporation by reference
• 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:

SAAB AB, SAAB Aerosystems: Docket No. FAA-2009-0134; Directorate Identifier 2008-NM-162-AD.

Comments Due Date

(a) We must receive comments by September 8, 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 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 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 or earlier: 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 [phone]; fax [phone]. 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.

Issued in Renton, Washington, on August 3, 2009.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.