### 19721 Federal Register / Vol. 76, No. 68 / Friday, April 8, 2011 / Proposed Rules

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–2011–0307; Directorate Identifier 2010–NM–111–AD.

Comments Due Date

(a) We must receive comments by May 23,
2011.

Affected ADs

(b) None.
Applicability

(c) This AD applies to all Saab AB, Saab Aerosystems Model SAAB 2000 airplanes, certificated in any category.
Subject

(d) Air Transport Association (ATA) of America Code 32: Landing gear.

Reason

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

A report has been received of an incident where one of the two bolts attaching the actuator mounting bracket to the MLG [main landing gear] Shock Strut was found loose, leading to failure of the other attachment bolt, subsequently resulting in failure of the bracket.

This condition, if not detected and corrected, could prevent the MLG to extend to the full down-and-locked position, possibly resulting in MLG collapse upon landing or during roll-out, with consequent damage to the aeroplane and injury to the occupants.
* * * * *
Compliance

(f) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Inspection

(g) Within 12 months after the effective date of this AD, do a detailed inspection for any loose top bolt and nut of the shock strutactuator mounting bracket of both the lefthand and right-hand main landing gear (MLG), in accordance with paragraph 2.B. of the Accomplishment Instructions of Saab Service Bulletin 2000–32–073, Revision 01, dated October 20, 2009.

Corrective Action

(h) If any loose bolt or nut is found during the inspection required by paragraph (g) of this AD, before further flight, replace the bolt with a new bolt and accomplish paragraphs (h)(1) and (h)(2) of this AD, in accordance with paragraph 2.C. of the Accomplishment Instructions Saab Service Bulletin 2000–32– 073, Revision 01, dated October 20, 2009.

(1) Do a detailed inspection of the bottom bolts for uniform or fretting corrosion. If any corrosion is found, before further flight, accomplish all applicable corrective actions, in accordance with the Accomplishment Instructions of Saab Service Bulletin 2000– 32–073, Revision 01, dated October 20, 2009.

(2) Do a detailed inspection for damage, cracks, and other signs of deterioration of the actuator mounting bracket and shock strut. If signs of damage, cracks, or other signs of deterioration are found on the actuator mounting bracket or the shock strut, before further flight, repair in accordance with a method approved by the FAA or the European Aviation Safety Agency (EASA) (or its delegated agent).

(i) Within 12 months after the effective date of this AD, unless already accomplished in accordance with paragraph (h) of this AD, install the correct number of washers for both the top and bottom bolts of the shock strut actuator mounting bracket of both MLG, in accordance with paragraph 2.C.of the Accomplishment Instructions of Saab Service Bulletin 2000–32–073, Revision 01, dated October 20, 2009.
Credit for Actions Accomplished in Accordance With Previous Service Information

(j) Actions accomplished before the effective date of this AD in accordance with Saab Service Bulletin 2000–32–073, dated June 26, 2009, are considered acceptable for compliance with the corresponding actions specified in this AD.

FAA AD Differences

Note 1: This AD differs from the MCAI and/or service information as follows: No differences.

Other FAA AD Provisions

(k) 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. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the International Branch, send it 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. Information may be e-mailed to: 9- ANM-116-AMOC-REQUESTS@faa.gov

. Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/ certificate holding district office. The AMOC approval letter must specifically reference this AD.

(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.

Related Information

(l) Refer to MCAI EASA Airworthiness Directive 2010–0069, dated April 14, 2010; and Saab Service Bulletin 2000–32–073, Revision 01, dated October 20, 2009; for related information.

Issued in Renton, Washington, on March 31, 2011. Kalene C. Yanamura, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 2011–8412 Filed 4–7–11; 8:45 am]

**BILLING CODE 4910–13–P**

**DEPARTMENT OF TRANSPORTATION**

**Federal Aviation Administration**

**14 CFR Part 39**

**[Docket No. FAA–2011–0308; Directorate Identifier 2010–NM–233–AD]** 

**RIN 2120–AA64**

**Airworthiness Directives; 328 Support Services GmbH (Type Certificate**  **Previously Held by AvCraft Aerospace GmbH; Fairchild Dornier GmbH;**  **Dornier Luftfahrt GmbH) Model 328– 100 and –300 Airplanes** 

**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) 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 maintenance, it has been discovered that at the installation of the fixation brackets for rudder spring tabs and trim tabs an incorrect installation of the fixation brackets may have occurred. * * *


### 19722 Federal Register / Vol. 76, No. 68 / Friday, April 8, 2011 / Proposed Rules

If the orientation of the fixation bracket is reversed or upside down the screws may not reach into the helicoil thread to a sufficient depth.

An incorrect installation, if not detected and corrected, could lead to an in-flight failure of the fixation brackets for rudder spring tabs and trim tabs resulting in and reduced control of the aeroplane. 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 May 23, 2011.

**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.

For service information identified in this proposed AD, contact 328 Support Services GmbH, Global Support Center, P.O. Box 1252, D–82231 Wessling, Federal Republic of Germany; telephone +49 8153 88111 6666; fax +49 8153 88111 6565; e-mail gsc.op@328support.de; Internet http:// www.328support.de. 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. 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.

**FOR FURTHER INFORMATION CONTACT :**  Tom Rodriguez, Aerospace Engineer, International Branch, ANM–116, Transport Airplane Directorate, FAA, 1601 Lind Avenue, SW., Renton, Washington 98057–3356; telephone (425) 227–1137; fax (425) 227–1149.

**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–2011–0308; Directorate Identifier 2010–NM–233–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

The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued EASA Airworthiness Directive 2010–0134, dated June 30, 2010 (referred to after this as ‘‘the MCAI’’ ), to correct an unsafe condition for the specified products. The MCAI states:

During maintenance, it has been discovered that at the installation of the fixation brackets for rudder spring tabs and trim tabs an incorrect installation of the fixation brackets may have occurred. It is possible that the fixation bracket assembly may be incorrectly orientated and as a result the position of the helicoil inserts on the fixation bracket may be incorrect.

If the orientation of the fixation bracket is reversed or upside down the screws may not reach into the helicoil thread to a sufficient depth.

An incorrect installation, if not detected and corrected, could lead to an in-flight failure of the fixation brackets for rudder spring tabs and trim tabs resulting in and reduced control of the aeroplane.

To address this potential unsafe condition, the TC [type certificate] holder has developed a one-time inspection to detect and correct any incorrect installations of the fixation brackets for rudder spring tabs and trim tabs.

For the reasons described above, this AD requires a one-time [detailed] inspection of all rudder trim- and spring tab fixation brackets, the correction of any parts that are incorrectly installed and the reporting of all findings to the TC holder. This AD is considered to be an interim action and an improved design bracket attachment is expected to be developed. The detailed inspection includes determining if the helicoil inserts of the rudder trim tab and spring tab fixation brackets are correctly oriented and are facing the fitting surface, and if not, inspecting the fittings and helicoil inserts for correct installation. The corrective actions include re-orienting the fittings and helicoil inserts, and replacing the fitting with a serviceable one. You may obtain further information by examining the MCAI in the AD docket.

Relevant Service Information

328 Support Services has issued Service Bulletins SB–328–55–493 (for Model 328–100 airplanes) and SB–328J– 55–245 (for Model 328–300 airplanes), both dated April 21, 2010, both including a Compliance Report. 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 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.

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 55 products of U.S. registry. We also estimate that it would take about 2 work-hours per product to comply with the basic requirements of this proposed AD. The average labor


### 19723 Federal Register / Vol. 76, No. 68 / Friday, April 8, 2011 / Proposed Rules

rate is $85 per work-hour. Based on these figures, we estimate the cost of the proposed AD on U.S. operators to be $9,350, or $170 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:
328 Support Services GmbH (Type Certificate Previously Held by AvCraft Aerospace GmbH; Fairchild Dornier GmbH; Dornier Luftfahrt GmbH): Docket No. FAA–2011–0308; Directorate Identifier 2010–NM–233–AD.

Comments Due Date

(a) We must receive comments by May 23,
2011.

Affected ADs

(b) None.
Applicability

(c) This AD applies to 328 Support Services GmbH (Type Certificate previously held by AvCraft Aerospace GmbH; Fairchild Dornier GmbH; Dornier Luftfahrt GmbH) Model 328–100 and –300 airplanes, certificated in any category, all serial numbers.
Subject

(d) Air Transport Association (ATA) of America Code 55: Stabilizers.

Reason

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

During maintenance, it has been discovered that at the installation of the fixation brackets for rudder spring tabs and trim tabs an incorrect installation of the fixation brackets may have occurred. * * *

If the orientation of the fixation bracket is reversed or upside down the screws may not reach into the helicoil thread to a sufficient depth.

An incorrect installation, if not detected and corrected, could lead to an in-flight failure of the fixation brackets for rudder spring tabs and trim tabs resulting in and reduced control of the aeroplane.
Compliance

(f) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Inspection

(g) Within 400 flight hours after the effective date of this AD, do a detailed inspection to determine if the fixation brackets for the rudder spring tabs and trim tabs are installed correctly, in accordance with the Accomplishment Instructions of 328 Support Services Service Bulletin SB–328– 55–493, dated April 21, 2010 (for Model 328– 100 airplanes); or SB–328J–55–245, dated April 21, 2010 (for Model 328–300 airplanes).

Corrective Action

(h) If, during the inspection required by paragraph (g) of this AD, any incorrect installation of the fixation brackets for rudder spring tabs and trim tabs is detected, before further flight, correct the installation of the fixation brackets for rudder spring tabs and trim tabs, in accordance with the Accomplishment Instructions of 328 Support Services Service Bulletin SB–328–55–493, dated April 21, 2010 (for Model 328–100 airplanes); or SB–328J–55–245, dated April 21, 2010 (for Model 328–300 airplanes).
Reporting

(i) Within 30 days after the inspection required by paragraph (g) of this AD, or within 30 days after the effective date of this AD, whichever occurs later: Send the inspection report to 328 Support Services GmbH by using the Compliance Report attached to 328 Support Services Service Bulletin SB–328–55–493, dated April 21, 2010 (for Model 328–100 airplanes); or SB– 328J–55–245, dated April 21, 2010 (for Model 328–300 airplanes). Send the report by mail or fax to: Attention: Dept. C, 328 Support Services GmbH, Customer Services, P.O. Box 1252, D–82231 Wessling, Federal Republic of Germany; fax +49 (0) 8153 88111–6565.

FAA AD Differences

Note 1: This AD differs from the MCAI and/or service information as follows: No differences.

Other FAA AD Provisions

(j) 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. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the International Branch/ACO, send it to ATTN: Tom Rodriguez, Aerospace Engineer, International Branch, ANM–116, Transport Airplane Directorate, FAA, 1601 Lind Avenue, SW., Renton, Washington 98057– 3356; telephone (425) 227–1137; fax (425) 227–1149. Information may be e-mailed to: 9-ANM-116-AMOC-REQUESTS@faa.gov

. Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/ certificate holding district office. The AMOC approval letter must specifically reference this AD.

(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: A Federal agency may not conduct or sponsor, and a person is not required to respond to, nor shall a person be subject to a penalty for failure to comply with a collection of information subject to the requirements of


### 19724 Federal Register / Vol. 76, No. 68 / Friday, April 8, 2011 / Proposed Rules

the Paperwork Reduction Act unless that collection of information displays a current valid OMB Control Number. The OMB Control Number for this information collection is 2120–0056. Public reporting for this collection of information is estimated to be approximately 5 minutes per response, including the time for reviewing instructions, completing and reviewing the collection of information. All responses to this collection of information are mandatory. Comments concerning the accuracy of this burden and suggestions for reducing the burden should be directed to the FAA at: 800 Independence Ave., SW., Washington, DC 20591, Attn: Information Collection Clearance Officer, AES–200.

Related Information

(k) Refer to MCAI European Aviation Safety Agency (EASA) Airworthiness Directive 2010–0134, dated June 30, 2010; and 328 Support Services Service Bulletins SB–328–55–493 and SB–328J–55–245, both dated April 21, 2010; for related information.

Issued in Renton, Washington, on March 31, 2011. Kalene C. Yanamura, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 2011–8414 Filed 4–7–11; 8:45 am]

**BILLING CODE 4910–13–P**

**DEPARTMENT OF TRANSPORTATION**

**Federal Aviation Administration**

**14 CFR Part 39**

**[Docket No. FAA–2011–0309; Directorate Identifier 2010–NM–255–AD]** 

**RIN 2120–AA64**

**Airworthiness Directives; Airbus Model A300 B4–600, B4–600R, and F4–600R**  **Series Airplanes, and Model C4–605R Variant F Airplanes (Collectively Called**  **A300–600 Series Airplanes); and Model A310 Series Airplanes** 

**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) 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:

A specific failure case of the THSA [trimmable horizontal stabilizer actuator] upper primary attachment, which may result in a loading of the upper secondary attachment, has been identified by analysis. Primary load path failure can be caused by bearing migration from the upper attachment gimbal by failure or loss of a retention bolt.

In case of failure of the THSA upper primary attachment, the THSA upper secondary attachment would engage. Because the upper attachment secondary load path can only withstand the loads for a limited period of time, the condition where it would be engaged could lead, if not detected, to the failure of the secondary load path, which would likely result in loss of control of the aeroplane. 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 May 23, 2011.

**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.

For service information identified in this proposed AD, contact Airbus SAS— EAW (Airworthiness Office), 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France; telephone +33 5 61 93 36 96; fax +33 5 61 93 44 51; e-mail account.airworth-eas@airbus.com; Internet http://www.airbus.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. 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.

**FOR FURTHER INFORMATION CONTACT :**  Dan Rodina, Aerospace Engineer, International Branch, ANM–116, Transport Airplane Directorate, FAA, 1601 Lind Avenue, SW., Renton, Washington 98057–3356; telephone (425) 227–2125; fax (425) 227–1149.

**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–2011–0309; Directorate Identifier 2010–NM–255–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

The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued EASA Airworthiness Directive 2010–0224, dated November 4, 2010 (referred to after this as ‘‘the MCAI’’ ), to correct an unsafe condition for the specified products. The MCAI states:

A specific failure case of the THSA [trimmable horizontal stabilizer actuator] upper primary attachment, which may result in a loading of the upper secondary attachment, has been identified by analysis.

Primary load path failure can be caused by bearing migration from the upper attachment gimbal by failure or loss of a retention bolt.

In case of failure of the THSA upper primary attachment, the THSA upper secondary attachment would engage. Because the upper attachment secondary load path can only withstand the loads for a limited period of time, the condition where it would be engaged could lead, if not detected, to the failure of the secondary load path, which would likely result in loss of control of the aeroplane.

For the reasons explained above, this AD requires installation of three secondary retention plates for the gimbal bearings on the THSA upper primary attachment. You may obtain further information by examining the MCAI in the AD docket.

Relevant Service Information

Airbus has issued Mandatory Service Bulletins A300–27–6066 (for Model A300–600 series airplanes) and A310– 27–2103 (for Model A310 series