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Proposed Rule

Airworthiness Directives; Saab Model SAAB 2000 Airplanes

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

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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:

One Part Number (P/N) LM-219-92 Centre Bracket from a P/N LM-219-SA28 Aft Engine Mounting assembly was found to be cracked while installed on the aircraft.

This reduces the effectiveness of the mounting assembly and could eventually cause it to fail.

* * * * *

A failed mounting assembly, if not corrected, could result in loss of the engine. 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 23, 2008.

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: (202) 493-2251.
  • 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.

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 (800) 647-5527) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

Start Further Info

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 (425) 227-1112; fax (425) 227-1149.

End Further Info End Preamble Start Supplemental Information

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-2008-0115; Directorate Identifier 2007-NM-240-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 5, 2008 (73 FR 6640). That earlier NPRM proposed to require actions intended to address the unsafe condition for the products listed above.

Since that NPRM was issued, the European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued EASA Airworthiness Directive 2008-0068, dated April 11, 2008 (referred to after this as “the MCAI”). The MCAI states:

One Part Number (P/N) LM-219-92 Centre Bracket from a P/N LM-219-SA28 Aft Engine Mounting assembly was found to be cracked while installed on the aircraft.

This reduces the effectiveness of the mounting assembly and could eventually cause it to fail.

EASA Airworthiness Directive (AD) was issued to require inspection and rework in order to make the centre bracket less sensitive to external damage that may result in a crack.

This AD, superseding AD 2007-0204, has been issued to introduce an alternative repeatable inspection procedure.

A failed mounting assembly, if not corrected, could result in loss of the engine. The corrective actions include an inspection to determine if there are any sharp edges on the aft engine mounting assembly; repetitive visual inspections, or a combination of visual and fluorescent penetrant inspection, for cracking of the center bracket of the aft engine mounting assembly for both engines; rework of sharp edges; replacement of the aft engine mounting assemblies; and re-identification of engine mounting assemblies and reworked center bracket. You may obtain further information by examining the MCAI in the AD docket.

Relevant Service Information

Saab has issued Saab Service Bulletin 2000-71-025, dated June 13, 2007, and Saab Service Bulletin 2000-71-023, Revision 01, dated June 13, 2007. 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.

Requests To Change Unsafe Condition

Rolls-Royce Corporation and Saab Aerosystems point out that the unsafe condition is stated incorrectly in the earlier NPRM. The unsafe condition in the earlier NPRM says “a failed mounting assembly, if not corrected, could result in loss of the engine.” The commenters state that the engine mounting assembly is designed as a redundant, multiple point mounting system and, in case of loss of one mount, the loads are transferred through the remaining mounts. Therefore, the mounting system is capable of flight with one mounting assembly completely inoperative, though the failure increases the load applied to the other mounting assemblies. Rolls-Royce states that Saab issued Service Bulletin 2000-71-025 (which we cited in the earlier NPRM) to ensure that the system redundancies are maintained.

We disagree with the request to change the wording of the unsafe condition. In an unsafe condition we define the end-level effect that condition could have on. In this case, a failed mounting assembly could compromise safety as the first in a Start Printed Page 50904potential chain of events that could result in loss of the engine. The unsafe condition emphasizes only the potential result by saying a failed mounting assembly could result in loss of the engine rather than saying it will result in loss of the engine. We have not changed the supplemental NPRM in this regard.

Request To Revise Difference Regarding Continued Flight With Cracks

Rolls-Royce and Saab also state that the “Differences” section in the NPRM incorrectly implies that Saab Service Bulletin 2000-71-025, and European Aviation Safety Agency (EASA) Airworthiness Directive 2007-0204, dated August 8, 2007, allow continued flight if a cracked center bracket is found. The commenters state that if any crack is found, the mounting assembly should be replaced before further flight.

When we evaluated the original EASA airworthiness directive, we found that it states that corrective actions are to be applied within 4,000 flight hours after its effective date. Because the EASA airworthiness directive does not specify that corrective actions are to be completed before further flight after the visual inspection, this means that operators can wait 4,000 flight hours to do the replacement, even though the inspection was required within 1,000 flight hours after the effective date. The service bulletin states that “If any cracks are found, replace the Aft Engine Mounting Assembly,” but does not give a specific time for doing that replacement. Therefore, we concluded that both documents can be interpreted to allow further flight with cracks. We also note that EASA Airworthiness Directive 2008-0068 maintains this same wording. Therefore, we have not changed the supplemental NPRM in this regard.

Statement of New Service Information

Saab states that it is working jointly with Rolls-Royce to develop an alternative means of compliance to the current non-destructive test (NDT) inspection specified in Saab Service Bulletin 2000-71-025. The proposed revision has been submitted to EASA and will most probably result in EASA issuing a revised airworthiness directive.

As stated earlier, EASA has issued Airworthiness Directive 2008-0068, and we have revised this supplemental NPRM accordingly. However, this supplemental NPRM still refers to Saab Service Bulletin 2000-71-025 because the service bulletin has not been revised. This supplemental NPRM also now refers to Saab Service Bulletin 2000-71-023, Revision 01 as an acceptable source of service information for doing certain actions. Once new service information is developed, approved, and available, we might consider additional rulemaking. We have not changed the AD in this regard.

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 about 6 products of U.S. registry. We also estimate that it would take about 8 work-hours per product to comply with the basic requirements of this proposed AD. The average labor rate is $80 per work-hour. Based on these figures, we estimate the cost of the proposed AD on U.S. operators to be $3,840, or $640 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.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Start Authority

Authority: 49 U.S.C. 106(g), 40113, 44701.

End Authority
[Amended]

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

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Saab Aircraft AB: Docket No. FAA-2008-0115; Directorate Identifier 2007-NM-240-AD.

Comments Due Date

(a) We must receive comments by September 23, 2008.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Saab Model SAAB 2000 airplanes, certificated in any category, serial number 004 through 063.

Subject

(d) Air Transport Association (ATA) of America Code 71: Powerplant.

Reason

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

One Part Number (P/N) LM-219-92 Centre Bracket from a P/N LM-219-SA28 Aft Engine Mounting assembly was found to be cracked while installed on the aircraft.

This reduces the effectiveness of the mounting assembly and could eventually cause it to fail.

EASA Airworthiness Directive (AD) was issued to require inspection and rework in order to make the centre bracket less sensitive to external damage that may result in a crack.

This AD, superseding AD 2007-0204, has been issued to introduce an alternative repeatable inspection procedure.

A failed mounting assembly, if not corrected, could result in loss of the engine. The corrective actions include an inspection to determine if there are any sharp edges on the aft engine mounting assembly; repetitive visual inspections, or a combination of visual and fluorescent penetrant inspection, for cracking of the center bracket of the aft engine mounting assembly for both engines; rework of sharp edges; replacement of the aft engine mounting assemblies; and re-identification of engine mounting assemblies and reworked center bracket.

Actions and Compliance

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

(1) Within 1,000 flight hours after the effective date of this AD, do visual inspections of both the aft engine mounting assemblies to find if the center bracket is correct (no sharp edges) from the manufacturer.

(2) If no sharp edge is found during the inspection required by paragraph (f)(1) of this AD, before further flight, inspect to determine if the aft engine mounting assembly and center bracket are identified with a “-1” and before further flight re-identify the parts that are not identified with a “-1” in accordance with the Accomplishment Instructions of Saab Service Bulletin 2000-71-025, dated June 13, 2007. Following the re-identification, no further action is required by this AD for airplanes on which no sharp edge is found during the inspection required by paragraph (f)(1) of this AD.

(3) If any sharp edge is found during the inspection required by paragraph (f)(1) of this AD, before further flight, do the action in paragraph (f)(3)(i) or (f)(3)(ii) of this AD in accordance with the Accomplishment Instructions of Saab Service Bulletin 2000-71-025, dated June 13, 2007.

(i) Do a general visual inspection for cracking of the center bracket of both of the aft engine mounting assemblies, with the bracket on the wing, and repeat the inspection thereafter at intervals not to exceed 250 flight hours until the action required by paragraph (f)(4) of this AD is accomplished.

(ii) Do general visual and penetrant inspections for cracking of the center bracket of both of the aft engine mounting assemblies, with the bracket off the wing.

Note 1:

For the purposes of this AD, a general visual inspection is: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to ensure visual access to all surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”

(4) At the applicable time in paragraph (f)(4)(i) or (f)(4)(ii) of this AD, do the applicable actions in those paragraphs in accordance with the Accomplishment Instructions of Saab Service Bulletin 2000-71-025, dated June 13, 2007. Doing the applicable action terminates the repetitive inspection requirements of paragraph (f)(3)(i) of this AD.

(i) If no cracking is found during any inspection required by paragraph (f)(3) of this AD: Within 4,000 flight hours after the effective date of this AD, rework the center bracket, and re-identify the aft engine mounting assembly and center bracket.

(ii) If any cracking is found during any inspection required by paragraph (f)(3) of this AD, before further flight, replace the aft engine mounting assembly with an assembly and bracket identified with a “-1” part number.

(5) Actions done before the effective date of this AD in accordance with Saab Service Bulletin 2000-71-023, Revision 01, dated June 13, 2007, are acceptable for compliance with the corresponding requirements of paragraph (f)(3) of this AD.

FAA AD Differences

Note 2:

This AD differs from the MCAI and/or service information as follows:

(1) Although the MCAI or service information allows further flight after cracks are found during compliance with the required action, paragraph (f)(4) of this AD requires that you replace a cracked aft engine mounting assembly before further flight.

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, Transport Airplane Directorate, 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 appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.

(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 (EASA) Airworthiness Directive 2008-0068, dated April 11, 2008, and Saab Service Bulletin 2000-71-025, dated June 13, 2007, for related information.

Start Signature

Issued in Renton, Washington, on August 20, 2008.

Kevin Hull,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. E8-20088 Filed 8-28-08; 8:45 am]

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