2666 Federal Register / Vol. 77, No. 12 / Thursday, January 19, 2012 / Proposed Rules 

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– 

2011–1415; Directorate Identifier 2011– 

NM–145–AD. 

(a) Comments Due Date 

We must receive comments by March 5, 

2012. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to all The Boeing 

Company Model 717–200 airplanes, 

certificated in any category. 

(d) Subject 

Joint Aircraft System Component (JASC)/ 

Air Transport Association (ATA) of America 

Code 5510, Horizontal Stabilizer Structure. 

(e) Unsafe Condition 

This AD was prompted by reports of cracks 

found on the center section ribs of the 

horizontal stabilizers. We are issuing this AD 

to detect and correct cracks in the left and 

right bearing lugs of the rib hinge spreading 

at the same time, which could result in 

failure of both hinge bearing lugs. Failure of 

the hinge bearing lugs could result in the 

inability of the horizontal stabilizer to sustain 

flight loads and therefore reduce the 

controllability of the airplane. 

(f) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(g) Repetitive Eddy Current High Frequency 

(ETHF) Inspections 

Before the accumulation of 35,000 total 

flight cycles, or within 8,275 flight cycles 

after the effective date of this AD, whichever 

occurs later: Do an ETHF inspection for 

cracks of the aft face on the left and right rib 

hinge bearing lugs of the center section of the 

horizontal stabilizer, in accordance with the 

Accomplishment Instructions of Boeing Alert 

Service Bulletin 717–55A0011, dated May 

17, 2011. If no crack is found, repeat the 

inspection thereafter at intervals not to 

exceed 10,500 flight cycles. 

(h) Crack Measurement 

If any crack is found during any inspection 

required by paragraph (g) of this AD: Before 

further flight, measure the length of the 

crack, in accordance with the 

Accomplishment Instructions of Boeing Alert 

Service Bulletin 717–55A0011, dated May 

17, 2011. 

(i) Blend Out Repair, ETHF Inspections, and 

Corrective Action for Certain Crack Lengths 

For any crack that meets ‘‘Condition 2A’’ 

of Table 1 of 1.E., ‘‘Compliance,’’ of Boeing 

Alert Service Bulletin 717–55A0011, dated 

May 17, 2011: Do the actions in paragraphs 

(i)(1) and (i)(2) of this AD. 

(1) Before further flight, do a blend out 

repair, in accordance with the 

Accomplishment Instructions of Boeing Alert 

Service Bulletin 717–55A0011, dated May 

17, 2011. 

(2) Within 14,200 flight cycles after 

accomplishing the blend out repair required 

by paragraph (i)(1) of this AD: Do an ETHF 

inspection of the blend out repair area for 

cracking, in accordance with the 

Accomplishment Instructions of Boeing Alert 

Service Bulletin 717–55A0011, dated May 

17, 2011. If no cracking is found, repeat the 

inspection thereafter at intervals not to 

exceed 5,400 flight cycles. 

(i) If any crack is found during the ETHF 

inspection required by paragraph (i)(2) of this 

AD: Before further flight, remove the cracked 

center section rib of the horizontal stabilizer 

and install a new center section rib, in 

accordance with the Accomplishment 

Instructions of Boeing Alert Service Bulletin 

717–55A0011, dated May 17, 2011. 

(ii) Within 35,000 flight cycles after the 

installation of the new center section rib, do 

the actions in paragraph (g) of this AD. 

(j) Corrective Action for Certain Crack 

Lengths 

For any crack that meets ‘‘Condition 2D’’ 

of Table 1 of 1.E., ‘‘Compliance,’’ of Boeing 

Alert Service Bulletin 717–55A0011, dated 

May 17, 2011: Before further flight, remove 

the cracked center section rib of the 

horizontal stabilizer and install a new center 

section rib, in accordance with the 

Accomplishment Instructions of Boeing Alert 

Service Bulletin 717–55A0011, dated May 

17, 2011. Within 35,000 flight cycles after the 

installation of the new rib, do the actions in 

paragraph (g) of this AD. 

(k) No Reporting Requirement 

Although Boeing Alert Service Bulletin 

717–55A0011, dated May 17, 2011, specifies 

to submit certain information to the 

manufacturer, this AD does not include that 

requirement. 

(l) Alternative Methods of Compliance 

(AMOCs) 

(1) The Manager Los Angeles 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. 

(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 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, Los Angeles 

ACO, to make those findings. For a repair 

method to be approved, the repair must meet 

the certification basis of the airplane, and the 

approval must specifically refer to this AD. 

(m) Related Information 

(1) For more information about this AD, 

contact George Garrido, Aerospace Engineer, 

Airframe Branch, ANM–120L, FAA, Los 

Angeles Aircraft Certification Office (ACO), 

3960 Paramount Boulevard, Lakewood, 

California 90712–4137; phone: (562) 627– 

5357; fax: (562) 627–5210; email: 

George.Garrido@faa.gov. 

(2) For service information identified in 

this AD, Boeing Commercial Airplanes, 

Attention: Data & Services Management, 3855 

Lakewood Boulevard, MC D800–0019, Long 

Beach, California 90846–0001; phone: (206) 

544–5000, extension 2; fax: (206) 766–5683; 

email: dse.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. 

Issued in Renton, Washington, on January 

6, 2012. 

Ali Bahrami, 

Manager, Transport Airplane Directorate, 

Aircraft Certification Service. 

[FR Doc. 2012–858 Filed 1–18–12; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2011–1417; Directorate 

Identifier 2011–NM–159–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 777 

airplanes. This proposed AD was 

prompted by reports that escape slides/ 

rafts did not deploy due to galvanic 

corrosion of the door-mounted slide/raft 

packboard release mechanisms. This 

proposed AD would require doing a 

general visual inspection of the housing 


EMCDONALD on DSK29S0YB1PROD with PROPOSALS
Federal Register / Vol. 77, No. 12 / Thursday, January 19, 2012 / Proposed Rules 2667 

assembly of the packboard release 

mechanism to determine if its surface 

treatment has been sealed, and if 

unsealed, replacing the housing 

assembly with a new or serviceable 

housing assembly. We are proposing 

this AD to detect and correct corrosion 

of the packboard release mechanisms, 

which could interfere with escape slide/ 

raft deployment, prohibit doors from 

opening in the armed mode, and cause 

consequent delay and injury during 

evacuation of passengers and crew from 

the cabin in the event of an emergency. 

DATES: We must receive comments on 

this proposed AD by March 5, 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 Boeing 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. For Air 

Cruisers service information identified 

in this AD, contact Air Cruisers 

Company, 1747 State Route 34, Wall, 

New Jersey 07727–3935; telephone: 

(732) 681–3527; fax: (732) 681–9163; 

email: 

Aircruisers@zodiacaerospace.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: Ana 

Martinez Hueto, Aerospace Engineer, 

Cabin Safety and Environmental 

Systems Branch, ANM–150S, FAA, 

Seattle Aircraft Certification Office 

(ACO), 1601 Lind Avenue SW., Renton, 

WA 98057–3356; phone: (425) 917– 

6592; fax: (425) 917–6591; email: 

ana.m.hueto@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– 

2011–1417; Directorate Identifier 2011– 

NM–159–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 that escape 

slides/rafts did not deploy due to 

galvanic corrosion of door-mounted 

slide/raft packboard release 

mechanisms. Such corrosion, if not 

detected and corrected, could interfere 

with escape slide/raft deployment, 

prohibit doors from opening in the 

armed mode, and cause consequent 

delay and injury during evacuation of 

passengers and crew from the cabin in 

the event of an emergency. 

Relevant Service Information 

We reviewed Boeing Special 

Attention Service Bulletin 777–25– 

0507, dated June 30, 2011. The service 

information describes procedures for 

doing a general visual inspection of the 

housing assembly of the door-mounted 

slide/raft packboard release mechanism 

to determine if its surface treatment has 

been sealed, and if unsealed, replacing 

the housing assembly with a new or 

serviceable housing assembly. 

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 these same 

type designs. 

Proposed AD Requirements 

This proposed AD would require 

accomplishing the actions specified in 

the service information described 

previously. 

Costs of Compliance 

We estimate that this proposed AD 

affects 161 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 ........................ Between 4 and 16 work-hours × $85 per 

hour = Between $340 and $1,360.

$0 Between $340 and 

$1,360.

Between $54,740 and 

$218,960. 

We estimate the following costs to do 

any necessary replacements 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 these replacements: 


EMCDONALD on DSK29S0YB1PROD with PROPOSALS
2668 Federal Register / Vol. 77, No. 12 / Thursday, January 19, 2012 / Proposed Rules 

ON-CONDITION COSTS

Action Labor cost Parts cost Cost per 

product 

Replacement .................................... 1 work-hour × $85 per hour = $85 ............................................................ $137 $222 

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– 

2011–1417; Directorate Identifier 2011– 

NM–159–AD. 

(a) Comments Due Date 

We must receive comments by March 5, 

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 Special 

Attention Service Bulletin 777–25–0507, 

dated June 30, 2011. 

(d) Subject 

Joint Aircraft System Component (JASC)/ 

Air Transport Association (ATA) of America 

Code 25, Equipment/Furnishings. 

(e) Unsafe Condition 

This AD was prompted by reports that 

escape slides/rafts did not deploy due to 

galvanic corrosion of the door-mounted 

slide/raft packboard release mechanisms. We 

are issuing this AD to detect and correct 

corrosion in the packboard release 

mechanisms, which could interfere with 

escape slide/raft deployment, prohibit doors 

from opening in the armed mode, and cause 

consequent delay and injury during 

evacuation of passengers and crew from the 

cabin in the event of an emergency. 

(f) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(g) Inspection and Replacement 

Within 42 months after the effective date 

of this AD, at the applicable passenger/crew 

entry doors identified in Boeing Special 

Attention Service Bulletin 777–25–0507, 

dated June 30, 2011: Do a general visual 

inspection of the housing assembly of the 

packboard release mechanism to determine if 

its surface treatment has been sealed; and if 

unsealed, before further flight, replace the 

housing assembly with a new or serviceable 

housing assembly, in accordance with the 

Accomplishment Instructions of Boeing 

Special Attention Service Bulletin 777–25– 

0507, dated June 30, 2011. 

Note 1: For the purposes of this AD, a 

general visual inspection is: ‘‘A visual 

examination of an interior or exterior area, 

installation, or assembly to detect obvious 

damage, failure, or irregularity. This level of 

inspection is made from within touching 

distance unless otherwise specified. A mirror 

may be necessary to ensure visual access to 

all surfaces in the inspection area. This level 

of inspection is made under normally 

available lighting conditions such as 

daylight, hangar lighting, flashlight, or 

droplight and may require removal or 

opening of access panels or doors. Stands, 

ladders, or platforms may be required to gain 

proximity to the area being checked.’’ 

Note 2: Boeing Special Attention Service 

Bulletin 777–25–0507, dated June 30, 2011, 

refers to Air Cruisers Service Bulletin 777 

107–25–30, dated September 30, 2010, as an 

additional source of guidance for inspecting 

and installing new housing assembly of the 

door-mounted slide/raft packboard release 

mechanism. 

(h) 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: -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. 

(i) Related Information 

(1) For more information about this AD, 

contact Ana Martinez Hueto, Aerospace 

Engineer, Cabin Safety and Environmental 

Systems Branch, ANM–150S, FAA, Seattle 

Aircraft Certification Office (ACO), 1601 Lind 

Avenue SW., Renton, WA 98057–3356; 

phone: (425) 917–6592; fax: (425) 917–6591; 

email: ana.m.hueto@faa.gov. 

(2) For Boeing 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; email 


EMCDONALD on DSK29S0YB1PROD with PROPOSALS
Federal Register / Vol. 77, No. 12 / Thursday, January 19, 2012 / Proposed Rules 2669 

me.boecom@boeing.com; Internet https:// 

www.myboeingfleet.com. For Air Cruisers 

service information identified in this AD, 

contact Air Cruisers Company, 1747 State 

Route 34, Wall, New Jersey 07727–3935; 

telephone: (732) 681–3527; fax: (732) 681– 

9163; email: 

Aircruisers@zodiacaerospace.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 January 

6, 2012. 

Ali Bahrami, 

Manager, Transport Airplane Directorate, 

Aircraft Certification Service. 

[FR Doc. 2012–856 Filed 1–18–12; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2011–1419; Directorate 

Identifier 2010–NM–281–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 737–300, –400, and 

–500 series airplanes. The existing AD 

currently requires repetitive inspections 

for cracking of the crown area of the 

fuselage skin, and corrective actions if 

necessary. Since we issued that AD, we 

received additional reports of cracking 

at the horizontal chem-mill steps away 

from the lap joints over the entire crown 

area, and vertical chem-mill cracks 

adjacent to the butt joints. This 

proposed AD would add repetitive 

inspections for cracking using different 

inspection methods and would inspect 

additional areas, and corrective actions 

if necessary. This proposed AD would 

also require additional repairs to 

previously repaired areas and repetitive 

inspections for loose fasteners and 

replacement if necessary in certain 

previously repaired areas. This 

proposed AD would also reduce certain 

compliance times and extend certain 

other compliance times. We are 

proposing this AD to detect and correct 

fatigue cracking of the fuselage skin, 

which could cause the fuselage skin to 

fracture and fail, and result in rapid 

decompression of the airplane. 

DATES: We must receive comments on 

this proposed AD by March 5, 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 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: 

Wayne Lockett, Aerospace Engineer, 

Airframe Branch, ANM–120S, FAA, 

Seattle Aircraft Certification Office, 

1601 Lind Avenue SW., Renton, 

Washington 98057–3356; phone: (425) 

917–6447; fax: (425) 917–6590; email: 

wayne.lockett@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–2011–1419; Directorate Identifier 

2010–NM–281–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 June 15, 2005, we issued AD 

2005–13–27, amendment 39–14164 (70 

FR 36821, June 27, 2005), for certain 

Boeing Model 737–300, –400, and –500 

series airplanes. That AD requires 

repetitive inspections for cracking of the 

crown area of the fuselage skin, and 

corrective actions if necessary. That AD 

resulted from a Model 737 fuselage 

structure test and fatigue analysis that 

indicate fuselage skin cracking could 

occur between 21,000 and 42,000 total 

flight cycles. We issued that AD to 

detect and correct fatigue cracking of the 

fuselage skin, which could cause the 

fuselage skin to fracture and fail, and 

result in rapid decompression of the 

airplane. 

Actions Since Existing AD Was Issued 

Since we issued AD 2005–13–27, 

amendment 39–14164 (70 FR 36821, 

June 27, 2005), additional reports of 

cracking at the horizontal chem-mill 

steps away from the lap joints over the 

entire crown area, and vertical chemmill cracks adjacent to the butt joints, 

have been received. Although there 

were no changes to the applicability in 

AD 2005–13–17, we have changed 

paragraph (c) of the proposed AD to 

refer to Boeing Alert Service Bulletin 

737–53A1234, Revision 2, dated 

November 24, 2010. 

Relevant Service Information 

We reviewed Boeing Alert Service 

Bulletin 737–53A1234, Revision 2, 

dated November 24, 2010. Boeing 

Special Attention Service Bulletin 737– 

53–1234, Revision 1, dated March 31, 

2005, was referred to for accomplishing 

the actions in AD 2005–13–27, 

amendment 39–14164 (70 FR 36821, 

June 27, 2005). Boeing Alert Service 

Bulletin 737–53A1234, Revision 2, 

dated November 24, 2010, describes 

procedures for repetitive nondestructive inspections (NDI) (medium 


EMCDONALD on DSK29S0YB1PROD with PROPOSALS