### 47230 Federal Register / Vol. 78, No. 150 / Monday, August 5, 2013 / Proposed Rules

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 airworthiness directive (AD): Thielert Aircraft Engines GmbH: Docket No. FAA–2013–0561; Directorate Identifier 2013–NE–23–AD.
(a) Comments Due Date

We must receive comments by October 4,
2013.
(b) Affected ADs

None. (c) Applicability

This AD applies to all Thielert Aircraft Engines GmbH TAE 125–01 reciprocating engines.
(d) Reason

This AD was prompted by a report of engine power loss due to engine coolant contaminating the engine clutch. The design of the engine allows the crankcase assembly opening to be susceptible to contamination from external sources. We are issuing this AD to prevent in-flight engine power loss, which could result in loss of control of, and damage to, the airplane.
(e) Actions and Compliance

Unless already done, do the following actions.

(1) After the effective date of this AD at the next annual or 100-hour inspection, whichever comes first, apply sealant to close the engine clutch housing (crankcase assembly) opening.

(2) Thereafter, reapply sealant to the engine clutch housing (crankcase assembly) opening, whenever the sealant is found to be not liquid-tight, or is removed.

(3) Guidance on the sealant and application can be found in Thielert Aircraft Engines GmbH Service Bulletin No.TM TAE 125–0022, dated August 8, 2012.
(f) Alternative Methods of Compliance (AMOCs)

The Manager, Engine Certification Office, FAA, may approve AMOCs to this AD. Use the procedures found in 14 CFR 39.19 to make your request.
(g) Related Information

(1) For more information about this AD, contact Frederick Zink, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; phone: 781–238–7779; fax: 781–238 7199; email: frederick.zink@faa.gov.

(2) Refer to European Aviation Safety Agency Airworthiness Directive 2013–0109, dated May 22, 2013, for related information. You may examine the AD on the Internet at http://ad.easa.europa.eu/ad/2013–0109

.

(3) Thielert Aircraft Engines GmbH Service Bulletin No. TM TAE 125–0022, dated August 8, 2012, which is not incorporated by reference in this AD, can be obtained from Thielert Aircraft Engines GmbH, using the contact information in paragraph (g)(4) of this AD.

(4) For service information identified in this AD, contact Thielert Aircraft Engines GmbH, Platanenstrasse 14 D–09350, Lichtenstein, Germany, telephone: +49– 37204–696–0; fax: +49–37204–696–55; email: info@centurion-engines.com. You may view this service information at the FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA. For information on the availability of this material at the FAA, call 781–238–7125.

Issued in Burlington, Massachusetts, on July 25, 2013. Thomas A. Boudreau, Acting Assistant Manager, Engine & Propeller Directorate, Aircraft Certification Service.
[FR Doc. 2013–18797 Filed 8–2–13; 8:45 am]

**BILLING CODE 4910–13–P**

**DEPARTMENT OF TRANSPORTATION**

**Federal Aviation Administration**

**14 CFR Part 39**

**[Docket No. FAA–2013–0679; Directorate Identifier 2009–SW–015–AD]** 

**RIN 2120–AA64**

**Airworthiness Directives; Eurocopter France (Eurocopter) Model Helicopters** 

**AGENCY :**  Federal Aviation Administration (FAA), DOT.

**ACTION :**  Notice of proposed rulemaking (NPRM).

**SUMMARY :**  We propose to adopt a new airworthiness directive (AD) for Eurocopter Model AS350B, AS350BA, AS350B1, AS350B2, AS350B3, AS350C, AS350D, and AS350D1 helicopters. This proposed AD would require measuring the distance between the end of the main rotor collective pitch lever (collective) locking stud (locking stud) and the locking strip and repairing the locking stud if the clearance is insufficient. This proposed AD is prompted by a report that insufficient distance between the locking stud and the locking strip may cause the collective to become inadvertently locked in the low pitch (low) position. The proposed actions are intended to prevent the collective from becoming inadvertently locked in the low position and subsequent loss of control of the helicopter.

**DATES :**  We must receive comments on this proposed AD by October 4, 2013.

**ADDRESSES :**  You may send comments by any of the following methods:

• Federal eRulemaking Docket: Go to http://www.regulations.gov. Follow the online instructions for sending your comments electronically.

• Fax: 202–493–2251.

• Mail: Send comments to the U.S. Department of Transportation, Docket Operations, M–30, West Building Ground Floor, Room W12–140, 1200 New Jersey Avenue SE., Washington, DC 20590–0001.

• Hand Delivery: Deliver to the ‘‘Mail’’ address 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 economic 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 service information identified in this proposed AD, contact American Eurocopter Corporation, 2701 N. Forum Drive, Grand Prairie, TX 75052; telephone (972) 641–0000 or (800) 232–0323; fax (972) 641–3775; or
at http://www.eurocopter.com/techpub. You may review the referenced service information at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.

**FOR FURTHER INFORMATION CONTACT :**  Robert Grant, Aviation Safety Engineer, Safety Management Group, FAA, 2601 Meacham Blvd., Fort Worth, Texas 76137; telephone 817–222–5110; email robert.grant@faa.gov.

**SUPPLEMENTARY INFORMATION :** 
Comments Invited

We invite you to participate in this rulemaking by submitting written comments, data, or views. We also


### 47231 Federal Register / Vol. 78, No. 150 / Monday, August 5, 2013 / Proposed Rules

invite comments relating to the economic, environmental, energy, or federalism impacts that might result from adopting the proposals in this document. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. To ensure the docket does not contain duplicate comments, commenters should send only one copy of written comments, or if comments are filed electronically, commenters should submit only one time.

We will file in the docket all comments that we receive, as well as a report summarizing each substantive public contact with FAA personnel concerning this proposed rulemaking. Before acting on this proposal, we will consider all comments we receive on or before the closing date for comments. We will consider comments filed after the comment period has closed if it is possible to do so without incurring expense or delay. We may change this proposal in light of the comments we receive.

Discussion

The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union, has issued EASA AD No. 2009– 0019, dated February 3, 2009, to correct an unsafe condition for the Eurocopter Model AS350 helicopters. EASA advises that the clearance between the collective locking stud and the locking strip may be insufficient when the collective is positioned in the low pitch stop. During an autorotation test flight, the collective rubbed against the locking strip in the low pitch position. The rubbing was due to inadequate clearance and could result in the collective being inadvertently locked in the low pitch position.

FAA’s Determination

These helicopters have been approved by the aviation authority of France and are approved for operation in the United States. Pursuant to our bilateral agreement with France, EASA, its technical representative, has notified us of the unsafe condition described in its AD. We are proposing this AD because we evaluated all known relevant information and determined that an unsafe condition is likely to exist or develop on other products of the same type design.

Related Service Information

Eurocopter issued Service Bulletin No. 67.00.37, Revision 2, dated December 2, 2008, originally issued on September 27, 2007, and also identified as modification (MOD) 073237, which contains procedures for replacing the locking stud on the collective levers with a new locking stud with higher wear resistance. The new locking stud is longer than the previous one and has reduced the distance between the locking stud and the locking strip. In some cases, the reduced distance is insufficient when the collective is positioned in the low pitch position causing the collective to lock in that position. As a result, Eurocopter has issued one Emergency Alert Service Bulletin (EASB), Revision 0, dated January 12, 2008, with two numbers. EASB No. 05.00.58 is for civil Model AS350B, BA, BB, B1, B2, B3, and D helicopters and military Model AS350L1 helicopters. EASB No. 05.00.35 is for military Model AS550A2, C2, C3, and U2 helicopters. The EASB specifies measuring to ensure a required minimum distance between the locking stud and the locking strip and specifies a repair solution in case the distance is insufficient. As a precaution, Eurocopter extended the measure and repair to helicopters with locking studs before MOD 073237. Eurocopter also revised Service Bulletin No. 67.00.37 to include these procedures. Proposed AD Requirements

The proposed AD would require measuring the clearance between the collective locking stud and the locking strip. If insufficient clearance exists, corrective actions are defined based on the installed locking strip and locking stud designs. Corrective actions include restoring the original profile of certain locking strips and adjusting the length of certain collective locking studs. Differences Between This Proposed AD and the EASA AD

The EASA AD does not apply to Model AS350C or AS350D1 helicopters, and the proposed AD would apply to these models because they have a similarly-designed collective pitch lock. The EASA AD applies to the Model AS350BB, and the proposed AD does not because that model does not have a U.S. type certificate. The proposed AD would require an initial inspection within 100 hours time-in-service, while the EASA AD requires this inspection ‘‘after the last flight of the day.’’ Costs of Compliance

We estimate that this proposed AD would affect 651 helicopters of U.S. Registry.

We estimate that operators may incur the following costs in order to comply with this AD. It would take 1 work hour to measure the clearance and repair the locking stud and locking strip at $85 per work hour. Required parts would cost $95 per helicopter. Based on these estimates, the total cost per helicopter would be $180, and the total cost for the fleet would be $117,180. 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, 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 to the extent that it justifies making a regulatory distinction; 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.

We prepared an economic 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,


### 47232 Federal Register / Vol. 78, No. 150 / Monday, August 5, 2013 / Proposed Rules

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 airworthiness directive (AD):
Eurocopter France: Docket No. FAA–2013– 0679; Directorate Identifier 2009–SW– 015–AD. (a) Applicability

This AD applies to Eurocopter Model AS350B, AS350BA, AS350B1, AS350B2, AS350B3, AS350C, AS350D, AS350D1 helicopters, certificated in any category, without modification (MOD) 073175 installed; with MOD 073237 installed in accordance with Eurocopter Service Bulletin No. 67.00.37 Revision 0, dated September 27, 2007, or Revision 1, dated February 6, 2008; or with one of the following serial numbers: 3972, 3973, 3982, 3987, 4003, 4023, 4046, 4050, 4086, 4120, 4122, 4132, 4143, 4152, 4172, 4194, 4259, 4314, 4324, 4378, 4392, 4447, 4452, 4477, 4489, 4490, 4501, 4523, 4546, 4560, 4589, 4594, 4599, 4632, 4659, 4666, or 4671.
(b) Unsafe Condition

This AD defines the unsafe condition as the main rotor collective pitch lever (collective) locking stud (locking stud) inadvertently locking in the low pitch (low) position, which could result in subsequent loss of control of the helicopter.
(c) Comments Due Date

We must receive comments by October 4,
2013. (d) Compliance

You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.
(e) Required Actions

(1) For helicopters with MOD 073237 installed, within 100 hours time-in-service (TIS):

(i) With the collective (item b) in the low position but not locked on the locking strip (item a), measure the distance between the end of the locking stud (item c) and the locking strip as indicated by dimension ‘‘J’’ in Figure 2 of Eurocopter Emergency Alert Service Bulletin No. 05.00.58, Revision 0, dated January 12, 2008 (EASB 05.00.58).

(ii) If the distance between the end of the locking stud and the locking strip is equal to or more than 3 millimeters (mm), no further action is required.

(iii) If the distance between the end of the locking stud and the locking strip is less than 3 mm and MOD 073175 is not installed, inspect to determine whether the grommet in the locking strip is seated against the console as shown in Figure 2 of the EASB. (A) If the grommet is not seated against the console, restore the original profile of the locking strip by doing the following:

( 1 ) Clamp the locking strip in a vice with soft jaws and apply load progressively to the locking strip to restore the original profile of the locking strip.

( 2 ) With the collective in the low position but not locked on the locking strip, measure the distance between the end of the locking stud and the locking strip as indicated by dimension ‘‘J’’ in Figure 2 of the EASB.

( 3 ) If the distance between the end of the locking stud and the locking strip is equal to or more than 3 mm, no further action is required.

( 4 ) If the distance between the end of the locking stud and the locking strip is less than 3 mm, adjust the length of the locking stud and re-identify the locking stud by following the Accomplishment Instructions, paragraph 2.B.2.c., of the EASB, except you are not required to comply with paragraph 2.B.4 of the EASB.

(B) If the grommet is seated against the console, adjust the length of the locking stud and re-identify the locking stud by following the Accomplishment Instructions, paragraph 2.B.2.c, of the EASB, except you are not required to comply with paragraph 2.B.4 of the EASB.

(iv) If the distance between the end of the locking stud and the locking strip is less than 3 mm and MOD 073175 is installed, adjust the length of the locking stud and re-identify the locking stud by following the Accomplishment Instructions, paragraph 2.B.2.c., of the EASB, except you are not required to comply with paragraph 2.B.4 of the EASB.

(v) After adjusting the length of the locking stud in accordance with paragraph 2.B.2.c of the EASB, determine whether the distance between the end of the locking stud and the locking strip is equal to or more than 3 mm.

(A) If the distance between the end of the locking stud and the locking strip is equal to or more than 3 mm, no further action is required.

(B) If the distance between the end of the locking stud and the locking strip is less than 3 mm, do not approve the helicopter for return to service until the distance between the end of the locking stud and the locking strip is equal to or more than 3 mm.

(2) For helicopters without MOD 073237 installed, within 100 hours TIS:

(i) With the collective in the low position but not locked on the locking strip, measure the distance between the end of the locking stud and the locking strip as indicated by dimension ‘‘J’ in Figure 2 of the EASB.

(ii) If the distance between the end of the locking stud and the locking strip is equal to or more than 3 mm, no further action is needed.

(iii) If the distance between the end of the locking stud and the locking strip is less than 3 mm and MOD 073175 is not installed, inspect to determine whether the grommet in the locking strip is seated against the console as shown in Figure 2 of the EASB.

(A) If the grommet is not seated against the console, restore the original profile of the locking strip by doing the following: (1) Clamp the locking strip in a vice with soft jaws and applying load progressively to the locking strip.

(2) With the collective in the low position, but not locked on the locking strip, measure the distance between the end of the locking stud and the locking strip as indicated by dimension ‘‘J’’ in Figure 2 of the EASB.

(3) If the distance between the end of the locking stud and the locking strip is equal to or more than 3 mm, no further action is required.

(4) If the distance between the end of the locking stud and the locking strip is less than 3 mm, do not approve the helicopter for return to service until the distance between the end of the locking stud and the locking strip is equal to or more than 3 mm.

(B) If the grommet is seated against the console, do not approve the helicopter for return to service until the distance between the end of the locking stud and the locking strip is equal to or more than 3 mm.

(iv) If the distance between the end of the locking stud and the locking strip is less than 3 mm and MOD 073175 is installed, do not approve the helicopter for return to service until the distance between the end of the locking stud and the locking strip is equal to or more than 3 mm.

(3) Repeat the measurement requirement in paragraphs (e)(1) or (e)(2) of this AD as applicable to your helicopter each time the collective, locking stud, or locking strip is replaced; each time the locking strip setting is readjusted; or at intervals not exceeding 660 hours time-in-service or 2 years, whichever occurs first.
(f) Alternative Methods of Compliance (AMOCs)

(1) The Manager, Safety Management Group, FAA, may approve AMOCs for this AD. Send your proposal to: Robert Grant, Aviation Safety Engineer, Safety Management Group, FAA, 2601 Meacham Blvd., Fort Worth, Texas 76137; telephone 817–222– 5110; email robert.grant@faa.gov

.

(2) For operations conducted under 14 CFR part 119 operating certificate or under 14 CFR part 91, subpart K, we suggest that you notify your principal inspector, or lacking a principal inspector, the manager of the local flight standards district office or certificate holding district office before operating any aircraft complying with this AD through an AMOC.
(g) Additional Information

(1) Eurocopter Emergency Alert Service Bulletin (EASB) No. 05.00.58, Revision 0, dated January 12, 2008, is co-published in one document with EASB No. 05.00.35, which is not incorporated by reference in this AD. Eurocopter Service Bulletin (SB) No. 67.00.21, Revision 1, dated June 21, 2006, and SB No. 67.00.37, Revision 2, dated December 2, 2008, which are not incorporated by reference, contain additional information about the subject of this AD.

(2) For service information identified in this AD, contact American Eurocopter Corporation, 2701 N. Forum Drive, Grand Prairie, TX 75052; telephone (972) 641–0000 or (800) 232–0323; fax (972) 641–3775; or at http://www.eurocopter.com/techpub . You


### 47233 Federal Register / Vol. 78, No. 150 / Monday, August 5, 2013 / Proposed Rules

may review the referenced service information at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.

(3) The subject of this AD is addressed in European Aviation Safety Agency (EASA) AD No. 2009–0019, dated February 3, 2009. You may view the EASA AD at http:// www.regulations.gov by searching for and locating it in Docket No. FAA–2013–0679.
(h) Subject

Joint Aircraft Service Component (JASC) Code: 6710 Main Rotor Control.

Issued in Fort Worth, Texas, on July 26,
2013. Kim Smith, Directorate Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 2013–18854 Filed 8–2–13; 8:45 am]

**BILLING CODE 4910–13–P**

**DEPARTMENT OF TRANSPORTATION**

**Federal Aviation Administration**

**14 CFR Part 39**

**[Docket No. FAA–2013–0670; Directorate Identifier 2013–NM–081–AD]** 

**RIN 2120–AA64**

**Airworthiness Directives; The Boeing Company Airplanes** 

**AGENCY :**  Federal Aviation Administration (FAA), DOT.

**ACTION :**  Notice of proposed rulemaking (NPRM).

**SUMMARY :**  We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 737–600, –700, –800, –900, and –900ER airplanes modified by particular supplemental type certificates (STC). This proposed AD was prompted by reports of cracks found during inspections of the in-flight entertainment system radome assembly. This proposed AD would require repetitive detailed inspections for cracks in the radome assembly, and replacement of the radome if necessary. We are proposing this AD to detect and correct cracks in the radome assembly, which could result in the radome (or pieces) separating from the airplane and striking the tail, and consequently reducing the controllability of the airplane.

**DATES :**  We must receive comments on this proposed AD by September 19,
2013.

**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: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this proposed AD, contact Live TV, 8900 Hangar Boulevard, Orlando, FL 32827; telephone 407–812–2600; fax 407–812– 2526; Internet http://www.livetv.net. 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 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 Office (phone: 800–647–5527) is in the

**ADDRESSES** section. Comments will be available in the AD docket shortly after receipt.

**FOR FURTHER INFORMATION CONTACT :**  Barry Culler, Aerospace Engineer, Airframe Branch, ACE–117A, FAA, Atlanta Aircraft Certification Office (ACO), 1701 Columbia Avenue, College Park, GA 30337; phone: 404–474–5546; fax: 404–474–5605; email: william.culler@faa.gov.

**SUPPLEMENTARY INFORMATION :** 
Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under the **ADDRESSES** section. Include ‘‘Docket No. FAA– 2013–0670; Directorate Identifier 2013– NM–081–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 because of 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 received reports of cracks in 26 radomes. The cracks were found during inspections of the radome assembly of various Model 737 series airplanes that had in-flight entertainment systems installed using certain STC issued to Live TV. The STC numbers are STC ST00284BO, http://rgl.faa.gov/ Regulatory

_and

_ Guidance

_Library/ rgstc.nsf/0/ 3ecc2e5e5f408bc1862579b30048ed60/ $FILE/ST00284BO.pdf; and STC ST02887AT, http://rgl.faa.gov/ Regulatory

_and

_ Guidance

_Library/ rgstc.nsf/0/ 9bf85b85ea3e295d8625735600721055/ $FILE/ST02887AT.pdf. Investigation of the cause of the cracks revealed that lack of dimensional controls on the radome manufacturing drawings can result in the introduction of preload stress on the radome during its assembly with the skirt fairing. Preload stress combined with flight or handling stress, such as maintenance personnel stepping on the radome fairing assembly, might initiate a crack. The radome manufacturing drawings were revised on September 13, 2010, to add a control dimension, which was incorporated into production at radome serial number 498. Cracks in the radome, if not corrected, could result in the radome (or pieces) separating from the airplane and striking the tail, and consequently reducing the controllability of the airplane.

Relevant Service Information

We reviewed Live TV Service Bulletin B737–53–0011

, dated March 29, 2013. The service information describes procedures for repetitive inspections for cracks in the outer ply of the radome and replacing the radome if any crack is found.

FAA’s Determination

We are proposing this AD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design. Proposed AD Requirements

This proposed AD would require accomplishing the actions specified in the service information described previously, except as discussed under ‘‘Differences Between the Proposed AD and the Service Information.’’ In