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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2015-0243; Directorate Identifier 2014-NM-114-AD]
          - RIN 2120-AA64

# AGENCY:

Federal Aviation Administration (FAA), DOT.

# ACTION:

Notice of proposed rulemaking (NPRM).

# SUMMARY:

                        We propose to adopt a new airworthiness directive (AD) for all                               ( print page 8572)                            Airbus Model A300 series airplanes; Model A300 B4-600, B4-600R, and F4-600R series airplanes, and A300 C4-605R Variant F airplanes (collectively called Model A300-600 series airplanes); and Model A310 series airplanes. This proposed AD was prompted by reports of cracked aluminum support struts of the trimmable horizontal stabilizer (THS) caused by stress corrosion. This proposed AD would require inspections to identify the part number of each support strut, repetitive inspections for cracking of the THS support strut ends, installation of reinforcing clamps on strut ends, and replacement of support struts, if necessary. We are proposing this AD to detect and correct cracked THS support struts, which could lead to the rupture of all four support struts making the remaining structure unable to carry limit loads, which could result in loss of the THS and reduced control of the airplane.                    

# DATES:

We must receive comments on this proposed AD by April 6, 2015.

# ADDRESSES:

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, 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 W12-140, 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, Airworthiness Office—EAW, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France; telephone +33 5 61 93 36 96; fax +33 5 61 93 44 51; email                         *account.airworth-eas@airbus.com;*                         Internet                         *http://www.airbus.com.*                         You may view this referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. 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*                     by searching for and locating Docket No. FAA-2015-0243; or in person at the Docket Management Facility 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, WA 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-2015-0243; Directorate Identifier 2014-NM-114-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 Union, has issued EASA Airworthiness Directive 2014-0164, dated July 11, 2014 (referred to after this as the Mandatory Continuing Airworthiness Information, or “the MCAI”), to correct an unsafe condition for all Airbus Model A300 series airplanes; Model A300 B4-600, B4-600R, and F4-600R series airplanes, and A300 C4-605R Variant F airplanes (collectively called Model A300-600 series airplanes); and Model A310 series airplanes. The MCAI states:

During scheduled maintenance, several Trimmable Horizontal Stabilizer (THS) support struts were found cracked at the strut ends. The THS is supported and articulated at frame (FR) 91 in the tail cone. Lateral movement is prevented by four diagonal support struts.

Investigations revealed that the cracks were caused by stress corrosion and propagated from the inside to the outside of the strut.

This condition, if not detected and corrected, could lead to the rupture of all four THS support struts at FR91, which would make the remaining structure unable to carry limit loads, potentially resulting in loss of the Horizontal Tail Plane.

                        To address this unsafe condition, EASA issued [EASA] AD 2014-0121 [                        *http://ad.easa.europa.eu/​ad/​2014-0121*] to require repetitive High Frequency Eddy Current (HFEC) inspections of the THS support strut ends, installation of reinforcing clamps on strut ends and, depending on findings, replacement of damaged support struts. Installation of reinforcing clamps on strut ends is considered a temporary solution pending introduction of a re-designed support strut.                    

Since that [EASA] AD was issued, it was discovered that the [EASA] AD appeared to also require HFEC inspections of steel struts, which are not prone to cracking. The unsafe condition exists only on support struts made of aluminum, which were introduced through Airbus modification (mod) 06101, but may also have been installed in service as replacement parts on aeroplanes in pre-mod 06101 configuration.

For the reason described above, this [EASA] AD retains the requirements of EASA AD 2014-0121, which is superseded, and clarifies the need for an initial identification of the support struts installed on aeroplanes in pre-mod 06101 configuration. The related Airbus Service Bulletins (SB) remain unchanged.

                    You may examine the MCAI in the AD docket on the Internet at                     *http://www.regulations.gov*                     by searching for and locating Docket No. FAA-2015-0243.                

## Relevant Service Information Under 1 CFR Part 51

Airbus has issued the following service information. The actions described in this service information are intended to correct the unsafe condition identified in the MCAI.
    - Airbus Service Bulletin A300-53-0394, dated February 14, 2014. This service information describes procedures for reinforcing the support struts of the THS at frame 91 in the fuselage tail section of Airbus Model A300 series airplanes.
    - Airbus Service Bulletin A300-53-0395, dated February 14, 2014. This service information describes procedures for inspecting for cracking of the support struts of the THS at frame 91 in the fuselage tail section of Airbus Model A300 series airplanes.
    - Airbus Service Bulletin A300-53-6172, dated February 14, 2014. This service information describes procedures for reinforcing the support struts of the THS at frame 91 in the fuselage tail section of Airbus Model A300-600 series airplanes.       ( print page 8573)      
    - Airbus Service Bulletin A300-53-6174, dated February 14, 2014. This service information describes procedures for inspecting for cracking of the support struts of the THS at frame 91 in the fuselage tail section of Airbus Model A300-600 series airplanes.
    - Airbus Service Bulletin A310-53-2136, dated February 14, 2014. This service information describes procedures for reinforcing the support struts of the THS at frame 91 in the fuselage tail section of Airbus Model A310 series airplanes.
    - Airbus Service Bulletin A310-53-2137, dated February 14, 2014. This service information describes procedures for inspecting for cracking of the support struts of the THS at frame 91 in the fuselage tail section of Airbus Model A310 series airplanes. This service information is reasonably available; see ADDRESSES                      for ways to access this service information.                

## 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 these same type designs.

## Differences Between This Proposed AD and the MCAI or Service Information

Unlike the procedures described in Airbus Service Bulletin A300-53-0395; Airbus Service Bulletin A300-53-6174; and Airbus Service Bulletin A310-53-2137; each dated February 14, 2014; this proposed AD would not permit further flight if cracks are detected in the aluminum support strut ends of the trimmable horizontal stabilizer at frame 91. We have determined that, because of the safety implications and consequences associated with that cracking, any cracked aluminum support strut ends of the trimmable horizontal stabilizer must be repaired or modified before further flight. This difference has been coordinated with EASA and Airbus.

## Costs of Compliance

We estimate that this proposed AD affects 174 airplanes of U.S. registry.

We also estimate that it would take about 5 work-hours per product to comply with the basic requirements of this proposed AD. The average labor rate is $85 per work-hour. Required parts would cost about $2,100 per product. Based on these figures, we estimate the cost of this proposed AD on U.S. operators to be $439,350, or $2,525 per product.

In addition, we estimate that any necessary follow-on actions would take about 15 work-hours and require parts costing $10,000, for a cost of $11,275 per product. We have no way of determining the number of aircraft that might need these actions.

## Paperwork Reduction Act

A federal agency may not conduct or sponsor, and a person is not required to respond to, nor shall a person be subject to penalty for failure to comply with a collection of information subject to the requirements of the Paperwork Reduction Act unless that collection of information displays a current valid OMB control number. The control number for the collection of information required by this proposed AD is 2120-0056. The paperwork cost associated with this proposed AD has been detailed in the Costs of Compliance section of this document and includes time for reviewing instructions, as well as completing and reviewing the collection of information. Therefore, all reporting associated with this proposed AD is 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.

## 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);

3. Will not affect intrastate aviation in Alaska; and

4. 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.

# 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 

2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD): 

**Airbus:**                         Docket No. FAA-2015-0243; Directorate Identifier 2014-NM-114-AD.                    

## (a) Comments Due Date

We must receive comments by April 6, 2015.

## (b) Affected ADs

None.

## (c) Applicability

This AD applies to the Airbus airplanes specified in paragraphs (c)(1) through (c)(6) of this AD, certificated in any category, all manufacturer serial numbers.

(1) Airbus Model A300 B2-1A, B2-1C, B2K-3C, B2-203, B4-2C, B4-103, and B4-203 airplanes.

(2) Airbus Model A300 B4-601, B4-603, B4-620, and B4-622 airplanes.

(3) Airbus Model A300 B4-605R and B4-622R airplanes.

                        (4) Airbus Model A300 F4-605R and F4-622R airplanes.                              ( print page 8574)    

(5) Airbus Model A300 C4-605R Variant F airplanes.

(6) Airbus Model A310-203, -204, -221, -222, -304, -322, -324, and -325 airplanes.

## (d) Subject

Air Transport Association (ATA) of America Code 53, Fuselage.

## (e) Reason

This AD was prompted by reports of cracked aluminum support struts of the trimmable horizontal stabilizer (THS) caused by stress corrosion. We are issuing this AD to detect and correct cracked THS support struts, which could lead to the rupture of all four support struts making the remaining structure unable to carry limit loads, which could result in loss of the THS and reduced control of the airplane.

## (f) Compliance

Comply with this AD within the compliance times specified, unless already done.

## (g) Inspection for Part Number

For airplanes in pre-modification 06101 configuration: Within 12 months after the effective date of this AD, do an inspection to identify the part number (P/N) of each support strut installed on the trimmable horizontal stabilizer (THS) at frame (FR) 91, in accordance with the Accomplishment Instructions of the applicable service bulletin identified in paragraphs (g)(1) through (g)(3) of this AD. A review of airplane maintenance records is acceptable in lieu of this inspection, provided those records can be relied upon for that purpose and the part number can be positively identified from that review. If no aluminum strut(s) having P/N R21449, R21449D, R21449G, or R21449H is found during any inspection required by this paragraph no further action is required by this AD for that horizontal stabilizer, except for paragraph (l) of this AD.

(1) For Airbus Model A300 series airplanes: Airbus Service Bulletin A300-53-0395, dated February 14, 2014.

(2) For Airbus Model A300 B4-600, B4-600R, and F4-600R series airplanes, and A300 C4-605R Variant F airplanes (collectively called Model A300-600 series airplanes): Airbus Service Bulletin A300-53-6174, dated February 14, 2014.

(3) For Airbus Model A310 series airplanes: Airbus Service Bulletin A310-53-2137, dated February 14, 2014.

## (h) Repetitive High Frequency Eddy Current (HFEC) Inspections

For airplanes in post-modification 06101 configuration; and for airplanes in pre-modification 06101 configuration on which one or more aluminum support strut(s) having P/N R21449, P/N R21449D, P/N R21449G, or P/N R21449H was found during the inspection by paragraph (g) of this AD: Within the applicable compliance times specified in paragraphs (h)(1), (h)(2), or (h)(3) of this AD, do an HFEC inspection for cracking of the aluminum THS support strut ends at FR 91, in accordance with the Accomplishment Instructions of the applicable service bulletin identified in paragraphs (g)(1) through (g)(3) of this AD. Reinforcing clamps already installed on strut ends must be removed before accomplishing the HFEC inspection and re-installed after the inspection, in accordance with the Accomplishment Instructions of the applicable service bulletin specified in paragraphs (g)(1) through (g)(3) of this AD. Repeat the inspection thereafter at intervals not to exceed 24 months.

(1) For airplanes having manufacturer serial number (MSN) 0499 through MSN 0747 inclusive (post-mod 06101): Within 12 months after the effective date of this AD.

(2) For airplanes having MSN 0748 through MSN 0878 inclusive (post-mod 06101): Within 18 months after the effective date of this AD.

(3) For airplanes having MSN 0001 through MSN 0498 inclusive (pre-mod 06101) having one or more aluminum struts: Within 24 months after the effective date of this AD.

## (i) Installation of Reinforcing Clamps

Concurrently with the initial HFEC inspection required by paragraph (h) of this AD, identify struts having P/N R21449, P/N R21449D, P/N R21449G, or P/N R21449H with no reinforcing clamps previously installed, and before next flight, install reinforcing clamps on each strut end, in accordance with the Accomplishment Instructions of the applicable service bulletin specified in paragraphs (i)(1) through (i)(3) of this AD.

(1) For Airbus Model A300 series airplanes: Airbus Service Bulletin A300-53-0394, dated February 14, 2014.

(2) For Airbus Model A300 B4-600, B4-600R, and F4-600R series airplanes, and A300 C4-605R Variant F airplanes (collectively called Model A300-600 series airplanes): Airbus Service Bulletin A300-53-6172, dated February 14, 2014.

(3) For Airbus Model A310 series airplanes: Airbus Service Bulletin A310-53-2136, dated February 14, 2014.

## (j) Corrective Actions

If, during any inspection required by paragraph (h) of this AD, any cracking is found, before further flight, replace the affected THS support strut(s) with serviceable struts and install clamps on each strut end, in accordance with the Accomplishment Instructions of the applicable service bulletin identified in paragraphs (g)(1) through (g)(3) of this AD.

## (k) Clarification

Installation of reinforcing clamps as required by paragraph (i) of this AD, and the replacement of support struts and/or the installation of clamps as required by paragraph (j) of this AD, do not constitute terminating action for the repetitive inspections required by paragraph (h) of this AD.

## (l) Reporting

At the applicable time specified in paragraphs (l)(1) and (l)(2) of this AD: After accomplishment of any inspection required by paragraphs (g) and (h) of this AD, report all inspection results to Airbus, including no findings, in accordance with the Accomplishment Instructions of the applicable service bulletins specified in paragraphs (g)(1) through (g)(3) of this AD, and paragraphs (i)(1) through (i)(3) of this AD.

(1) If the inspection was done on or after the effective date of this AD: Submit the report within 30 days after the inspection.

(2) If the inspection was done before the effective date of this AD: Submit the report within 30 days after the effective date of this AD.

## (m) Other FAA AD Provisions

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: Dan Rodina, Aerospace Engineer, International Branch, ANM-116, Transport Airplane Directorate, FAA, 1601 Lind Avenue SW., Renton, WA 98057-3356; telephone 425-227-2125; fax 425-227-1149. Information may be emailed 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)                         *Contacting the Manufacturer:*                         For any requirement in this AD to obtain corrective actions from a manufacturer, the action must be accomplished using a method approved by the Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA; or the European Aviation Safety Agency (EASA); or Airbus's EASA Design Organization Approval (DOA). If approved by the DOA, the approval must include the DOA-authorized signature.                    

                        (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 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.                    

## (n) Related Information

                        (1) Refer to Mandatory Continuing Airworthiness Information (MCAI) European                               ( print page 8575)                            Aviation Safety Agency Airworthiness Directive 2014-0164, dated July 11, 2014, for related information. This MCAI may be found in the AD docket on the Internet at                         *http://www.regulations.gov*                         by searching for and locating Docket No. FAA-2015-0243.                    

                        (2) For service information identified in this AD, contact Airbus SAS, Airworthiness Office—EAW, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France; telephone +33 5 61 93 36 96; fax +33 5 61 93 44 51; email                         *account.airworth-eas@airbus.com;*                         Internet                         *http://www.airbus.com.*                         You may view this service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221.                    

Issued in Renton, Washington, on February 2, 2015.

Dionne Palermo,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

[FR Doc. 2015-02922 Filed 2-17-15; 8:45 am]

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