34876 Federal Register / Vol. 77, No. 113 / Tuesday, June 12, 2012 / Proposed Rules 

(a) Comments Due Date 

We must receive comments by July 27, 

2012. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to Bombardier, Inc. Model 

DHC–8–400, –401, and –402 airplanes; 

certificated in any category; serial numbers 

4001, 4003 and subsequent, equipped with 

rudder feel trim unit part number 399500– 

1007. 

(d) Subject 

Air Transport Association (ATA) of 

America Code 27: Flight Controls. 

(e) Reason 

This AD was prompted by reports of 

movement of the rudder pedals being 

impeded due to corrosion of the trunnion 

shaft of the rudder feel trim unit (RFTU). 

We are issuing this AD to detect and 

correct any sign of seizure of the trunnion 

shaft and its bushing, which could cause a 

rudder control jam or a large and rapid 

alternating rudder input leading to a 

structural failure of the vertical fin. 

(f) Compliance 

You are responsible for having the actions 

required by this AD performed within the 

compliance times specified, unless the 

actions have already been done. 

(g) Inspection 

Within 600 flight hours or six months after 

the effective date of this AD whichever 

occurs first, inspect the RTFU to determine 

whether the serial number (S/N) is in the 

range from 0009 through 0388 without a 

suffix ‘‘A,’’ in accordance with the 

Accomplishment Instructions of Bombardier 

Service Bulletin 84–27–57, dated July 22, 

2011. A review of airplane maintenance 

records is acceptable in lieu of this 

inspection if the serial number of the RFTU 

can be conclusively determined from that 

review. 

(1) If the RFTU’s serial number is not in 

the range from 0009 through 0388 or if the 

serial number has a suffix ‘‘A,’’ no further 

action is required for this paragraph. 

(2) If the RFTU’s serial number is in the 

range from 0009 through 0388 without a 

suffix ‘‘A,’’ before further flight, perform an 

operational check of the RFTU for any sign 

of seizure of the trunnion and its bushing, in 

accordance with the Accomplishment 

Instructions of Bombardier Service Bulletin 

84–27–57, dated July 22, 2011. 

(i) If a seizure of the RFTU trunnion and 

its bushings is found: Before further flight, 

replace the RFTU with a new RFTU, in 

accordance with the Accomplishment 

Instructions of Bombardier Service Bulletin 

84–27–57, dated July 22, 2011. 

(ii) If no seizure of the RFTU trunnion and 

its bushings is found: Before further flight, 

lubricate the RFTU, in accordance with the 

Accomplishment Instructions of Bombardier 

Service Bulletin 84–27–57, dated July 22, 

2011. Repeat the lubrication of the RFTU at 

intervals not to exceed 600 flight hours until 

the replacement required by paragraph (h) is 

done. 

(h) Replacement 

For airplanes identified in paragraph (g)(2) 

of this AD: Within 6,000 flight hours after the 

effective date of this AD, replace all affected 

RFTUs with units that have a serial number 

outside the range from 0009 through 0388 or 

that have a serial number with a suffix ‘‘A,’’ 

in accordance with the Accomplishment 

Instructions of Bombardier Service Bulletin 

84–27–57, dated July 22, 2011. 

(i) Parts Installation 

As of the effective date of this AD, no 

person may install a RFTU P/N 399500–1007 

with a serial number from 0009 through 0388 

without a suffix ‘‘A’’ on any airplane. 

(j) Other FAA AD Provisions 

The following provisions also apply to this 

AD: 

(1) Alternative Methods of Compliance 

(AMOCs): The Manager, New York Aircraft 

Certification Office (ACO), ANE–170, 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 ACO, send it to ATTN: 

Program Manager, Continuing Operational 

Safety, FAA, New York ACO, 1600 Stewart 

Avenue, Suite 410, Westbury, New York 

11590; telephone 516–228–7300; fax 516– 

794–5531. 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. 

(k) Related Information 

(1) Refer to MCAI Canadian Airworthiness 

Directive CF–2012–02, dated January 9, 2012; 

and Bombardier Service Bulletin 84–27–57, 

dated July 22, 2011; for related information. 

(2) For service information identified in 

this AD, contact Bombardier, Inc., Q–Series 

Technical Help Desk, 123 Garratt Boulevard, 

Toronto, Ontario M3K 1Y5, Canada; 

telephone 416–375–4000; fax 416–375–4539; 

email thd.qseries@aero.bombardier.com; 

Internet http://www.bombardier.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. 

Issued in Renton, Washington, on May 31, 

2012. 

Michael Kaszycki, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service. 

[FR Doc. 2012–14212 Filed 6–11–12; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2012–0595; Directorate 

Identifier 2012–NM–055–AD] 

RIN 2120–AA64 

Airworthiness Directives; The Boeing 

Company 

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 777 

airplanes. This proposed AD was 

prompted by reports of failure of wire 

support clamps in the forward section of 

the aft pressure bulkhead. This 

proposed AD would require a detailed 

inspection of the clamps on the power 

feeder cable auxiliary power unit (APU) 

to determine if certain clamps are 

installed, and related investigative and 

corrective actions if necessary. We are 

proposing this AD to prevent failure of 

the clamp, which could result in wire 

chafing and potential arcing and 

consequent fire in section 48 (a 

flammable fluid leakage zone) or heat 

damage to the APU power feeder cable, 

insulation blankets, or pressure 

bulkhead. 

DATES: We must receive comments on 

this proposed AD by July 27, 2012. 

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 Boeing 

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Federal Register / Vol. 77, No. 113 / Tuesday, June 12, 2012 / Proposed Rules 34877 

Commercial Airplanes, Attention: Data 

& Services Management, P.O. Box 3707, 

MC 2H–65, Seattle, Washington 98124– 

2207; telephone 206–544–5000, 

extension 1; fax 206–766–5680; Internet 

https://www.myboeingfleet.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 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: 

Georgios Roussos, Aerospace Engineer, 

Systems and Equipment Branch, ANM– 

130S, FAA, Seattle Aircraft Certification 

Office, 1601 Lind Avenue SW., Renton, 

WA 98057–3356; phone: (425) 917– 

6482; fax: (425) 917–6590; email: 

georgios.roussos@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–

2012–0595; Directorate Identifier 2012– 

NM–055–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 have received reports of failure of 

wire support clamps in the forward 

section of the aft pressure bulkhead. 

This condition, if not corrected, could 

result in wire chafing and potential 

arcing and consequent fire in section 48 

(a flammable fluid leakage zone) or heat 

damage to the APU power feeder cable, 

insulation blankets, or pressure 

bulkhead. 

Relevant Service Information 

We reviewed Boeing Alert Service 

Bulletin 777–24A0119, dated November 

11, 2011. The service information 

describes procedures for a detailed 

inspection of the clamps on the APU 

power feeder cable to determine if 

certain clamps are installed, and related 

investigative and corrective actions if 

necessary. 

The related investigative actions 

include a general visual inspection for 

damage of the APU power feeder cable 

and heat damage of the insulation 

blanket adjacent to the clamp, a detailed 

inspection for primer discoloration and 

structural deterioration of the fuselage 

structure, and an eddy current 

inspection for heat damage of the 

aluminum structure. 

The corrective actions include 

replacing the affected clamps, repairing 

the APU power feeder cable, the 

installation blanket, and the aluminum 

structure. 

Clarification of Requirements 

Boeing Alert Service Bulletin 777– 

24A0119, dated November 11, 2011, 

does not include a step for the 

corrective action if no damage is found 

during the detailed inspection for 

primer discoloration and structural 

deterioration of the section 47 and 48 

fuselage structure. For the corrective 

action, this AD requires repairing the 

APU power feeder cable and insulation 

blanket and replacing the existing nonTA027063 clamps with TA027063 

clamps, in accordance with the 

Accomplishment Instructions of Boeing 

Alert Service Bulletin 777–24A0119, 

dated November 11, 2011. 

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.’’ 

Differences Between the Proposed AD 

and the Service Information 

The service bulletin specifies to 

contact the manufacturer for 

instructions on how to repair certain 

conditions, but this proposed AD would 

require repairing those conditions in 

one of the following ways: 

• In accordance with a method that 

we approve; or 

• Using data that meet the 

certification basis of the airplane, and 

that have been approved by the Boeing 

Commercial Airplanes Organization 

Designation Authorization (ODA) whom 

we have authorized to make those 

findings. 

Costs of Compliance 

We estimate that this proposed AD 

affects 164 airplanes of U.S. registry. 

We estimate the following costs to 

comply with this proposed AD: 

ESTIMATED COSTS

Action Labor cost Parts cost Cost per 

product 

Cost on U.S. 

operators 

Inspection and Clamp Replacement ............... 8 work-hours × $85 per hour = $680 ............. $500 $1,180 $193,520 

We estimate the following costs to do 

any necessary repair that would be 

required based on the results of the 

proposed inspection. We have no way of 

determining the number of aircraft that 

might need this repair: 

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34878 Federal Register / Vol. 77, No. 113 / Tuesday, June 12, 2012 / Proposed Rules 

ON-CONDITION COSTS

Action Labor cost Parts cost Cost per 

product 

Inspection and Repair of the Pressure Bulkhead ........ 48 work-hours × $85 per hour = $4,080 ...................... $0 $4,080 

We have received no definitive data 

that would enable us to provide parts 

cost estimates for the on-condition 

repairs specified in this proposed AD. 

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 [Amended] 

2. The FAA amends § 39.13 by adding 

the following new airworthiness 

directive (AD): 

The Boeing Company: Docket No. FAA– 

2012–0595; Directorate Identifier 2012– 

NM–055–AD. 

(a) Comments Due Date 

We must receive comments by July 27, 

2012. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to The Boeing Company 

Model 777–200, –200LR, –300, –300ER, and 

777F series airplanes; certificated in any 

category; as identified in Boeing Alert 

Service Bulletin 777–24A0119, dated 

November 11, 2011. 

(d) Subject 

Joint Aircraft System Component (JASC)/ 

Air Transport Association (ATA) of America 

Code 2421; AC Generator/Alternator. 

(e) Unsafe Condition 

This AD was prompted by reports of failure 

of wire support clamps in the forward section 

of the aft pressure bulkhead. We are issuing 

this AD to prevent failure of the clamp, 

which could result in wire chafing and 

potential arcing and consequent fire in 

section 48 (a flammable fluid leakage zone) 

or heat damage to the auxiliary power unit 

(APU) power feeder cable, insulation 

blankets, or pressure bulkhead. 

(f) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(g) Detailed Inspection of the Clamps 

Within 48 months after the effective date 

of this AD: Do a detailed inspection of the 

clamps on the APU power feeder cable to 

determine if TA027063 clamps are installed, 

and all applicable related investigative and 

corrective actions, in accordance with the 

Accomplishment Instructions of Boeing Alert 

Service Bulletin 777–24A0119, dated 

November 11, 2011, except as required by 

paragraph (h) and (i) of this AD. Do all 

related investigative and corrective actions 

before further flight. 

(h) Exception to the Service Bulletin 

If during any inspection of the fuselage 

structure required by paragraph (g) of this 

AD, no primer discoloration or structural 

deterioration is found, before further flight, 

repair the APU power feeder cable and 

insulation blanket and replace the existing 

clamps, in accordance with steps 3.B.7, 3.B.8, 

and 3.B.9 of the Accomplishment 

Instructions of Boeing Alert Service Bulletin 

777–24A0119, dated November 11, 2011. 

(i) Repair Approval 

Where the service bulletin specifies to do 

the repair in accordance to the instruction 

from Boeing, before further flight, repair 

using a method approved in accordance with 

the procedures specified in paragraph (j) of 

this AD. 

(j) Alternative Methods of Compliance 

(AMOCs) 

(1) The Manager, Seattle Aircraft 

Certification Office (ACO), 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 manager of the ACO, send it to the 

attention of the person identified in the 

Related Information section of this AD. 

Information may be emailed to: 9-ANMSeattle-ACO-AMOC-Requests@faa.gov. 

(2) 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. 

(3) An AMOC that provides an acceptable 

level of safety may be used for any structural 

repair required by this AD if it is approved 

by the Boeing Commercial Airplanes 

Organization Designation Authorization 

(ODA) that has been authorized by the 

Manager, Seattle ACO, to make those 

findings. For a structural repair method to be 

approved, the repair must meet the 

certification basis of the airplane, and the 

approval must specifically refer to this AD. 

(k) Related Information 

(1) For more information about this AD, 

contact Georgios Roussos, Aerospace 

Engineer, Systems and Equipment Branch, 

ANM–130S, FAA, Seattle Aircraft 

Certification Office, 1601 Lind Avenue SW., 

Renton, WA 98057–3356; phone: (425) 917– 

6482; fax: (425) 917–6590; email: 

georgios.roussos@faa.gov. 

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Federal Register / Vol. 77, No. 113 / Tuesday, June 12, 2012 / Proposed Rules 34879 

(2) For service information identified in 

this AD, contact Boeing Commercial 

Airplanes, Attention: Data & Services 

Management, P. O. Box 3707, MC 2H–65, 

Seattle, Washington 98124–2207; telephone 

206–544–5000, extension 1; fax 206–766– 

5680; Internet https:// 

www.myboeingfleet.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. 

Issued in Renton, Washington, on May 31, 

2012. 

Michael Kaszycki, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service. 

[FR Doc. 2012–14252 Filed 6–11–12; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2012–0591; Directorate 

Identifier 2012–NM–015–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 supersede an 

existing airworthiness directive (AD) 

that applies to certain The Boeing 

Company Model 737–600, –700, –700C, 

–800, and –900 series airplanes. The 

existing AD currently requires replacing 

the drain tube assemblies and support 

clamps on the aft fairing of the engine 

struts. Since we issued that AD, we 

received an additional report of a 

broken drain tube assembly on the aft 

fairing of the left engine strut at the 

clamp support location under the aft 

fairing compartment, inside the heat 

shield cavity of the aft fairing. There 

have also been reports of tube wear at 

the clamp location on additional 

airplanes. This proposed AD would 

require replacing the drain tube 

assembly of the left and right engine 

strut aft fairings with a new one which 

includes an integral support clamp 

made of nickel alloy 625. This proposed 

AD would also add airplanes to the 

applicability. We are proposing this AD 

to prevent failure of the drain tube 

assemblies and clamps on the aft 

fairings of the engine struts. Such failure 

could allow leaked flammable fluids in 

the drain systems to discharge onto the 

heat shields of the aft fairings of the 

engine struts, which could result in an 

undetected and uncontrollable fire. 

DATES: We must receive comments on 

this proposed AD by July 27, 2012. 

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 Boeing 

Commercial Airplanes, Attention: Data 

& Services Management, P.O. Box 3707, 

MC 2H–65, Seattle, Washington 98124– 

2207; telephone 206–544–5000, 

extension 1; fax 206–766–5680; email 

me.boecom@boeing.com; Internet 

https://www.myboeingfleet.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 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: 

Ansel James, Aerospace Engineer, 

Propulsion Branch, ANM–140S, FAA, 

Seattle Aircraft Certification Office, 

1601 Lind Avenue SW., Renton, 

Washington 98057–3356; phone: 425– 

917–6497; fax: 425–917–6590; email: 

ansel.james@faa.gov. 

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–2012–0591; Directorate Identifier 

2012–NM–015–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 

On April 8, 2008, we issued AD 2008– 

08–24, Amendment 39–15478 (73 FR 

21242, April 21, 2008), for certain 

Model 737–600, –700, –700C, –800, and 

–900 series airplanes. That AD requires 

replacing the drain tube assemblies and 

support clamps on the aft fairing of the 

engine struts. That AD resulted from 

reports of failure of the drain tube 

assembly and clamp on the aft fairings 

of an engine strut. We issued that AD to 

prevent failure of the drain tube 

assemblies and clamps on the aft 

fairings of the engine struts. Failure of 

the drain tube assemblies could allow 

leaked flammable fluids in the drain 

systems to discharge onto the heat 

shields of the aft fairings of the engine 

struts, which could result in an 

undetected and uncontrollable fire. 

Actions Since Existing AD Was Issued 

AD 2008–08–24, Amendment 39– 

15478 (73 FR 21242, April 21, 2008), 

refers to Boeing Special Attention 

Service Bulletin 737–54–1043, dated 

May 2, 2007, as the appropriate source 

of service information for the required 

actions. 

Boeing then issued Special Attention 

Service Bulletin 737–54–1043, Revision 

1, dated October 19, 2009, to replace the 

drain tube assembly of the engine strut 

aft fairing and support clamp. 

Since we issued AD 2008–08–24, 

Amendment 39–15478 (73 FR 21242, 

April 21, 2008), an airplane on which 

the actions specified in Boeing Special 

Attention Service Bulletin 737–54– 

1043, Revision 1, dated October 19, 

2009, had been incorporated in 

production, was reported to have a 

broken drain tube assembly on the aft 

fairing of the left engine strut at the 

clamp support location under the aft 

fairing compartment, inside the heat 

shield cavity of the aft fairing (the same 

location identified in the existing AD). 

mstockstill on DSK4VPTVN1PROD with PROPOSALS