Federal Register / Vol. 76, No. 45 / Tuesday, March 8, 2011 / Proposed Rules 12619 

Issued in Renton, Washington on February 

22, 2011. 

Kalene C. Yanamura, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service. 

[FR Doc. 2011–5158 Filed 3–7–11; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2011–0155; Directorate 

Identifier 2009–NM–141–AD] 

RIN 2120–AA64 

Airworthiness Directives; The Boeing 

Company 737–200, –200C, –300, –400, 

and –500 Series Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), Department of 

Transportation (DOT). 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: The FAA proposes to 

supersede an existing airworthiness 

directive (AD) that applies to certain 

Boeing Model 737–200, –200C, –300, 

–400, and –500 series airplanes. The 

existing AD currently requires repetitive 

inspections to find fatigue cracking of 

certain upper and lower skin panels of 

the fuselage, and follow-on and 

corrective actions if necessary. The 

existing AD also includes a terminating 

action for the repetitive inspections of 

certain modified or repaired areas only. 

This proposed AD would add new 

inspections for cracking of the fuselage 

skin along certain chem-milled lines, 

and corrective actions if necessary. This 

proposed AD would also reduce certain 

thresholds and intervals required by the 

existing AD. This proposed AD results 

from reports of new findings of vertical 

cracks in the fuselage skin along the 

chem-milled steps adjacent to the butt 

joints. We are proposing this AD to 

detect and correct fatigue cracking of the 

skin panels, which could result in 

sudden fracture and failure of the skin 

panels of the fuselage, and consequent 

rapid decompression of the airplane. 

DATES: We must receive comments on 

this proposed AD by April 22, 2011. 

ADDRESSES: You may send comments by 

any of the following methods: 

• Federal eRulemaking Portal: Go to 

http://www.regulations.gov. Follow the 

instructions for submitting comments. 

• Fax: 202–493–2251. 

• Mail: U.S. Department of 

Transportation, Docket Operations, 

M–30, West Building Ground Floor, 

Room W12–140, 1200 New Jersey 

Avenue, SE., Washington, DC 20590. 

• Hand Delivery: U.S. Department of 

Transportation, Docket Operations, 

M–30, West Building Ground Floor, 

Room W12–140, 1200 New Jersey 

Avenue, SE., Washington, DC 20590, 

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; e-mail 

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 

(telephone 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; telephone 

(425) 917–6447; fax (425) 917–6590; 

e-mail: 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–2011–0155; Directorate Identifier 

2009–NM–141–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 August 26, 2004, we issued AD 

2004–18–06, Amendment 39–13784 (69 

FR 54206, September 8, 2004), for 

certain Model 737–200, –200C, –300, 

–400, and –500 series airplanes. That 

AD requires repetitive inspections to 

find fatigue cracking of certain upper 

and lower skin panels of the fuselage, 

and follow-on and corrective actions if 

necessary. That AD also includes a 

terminating action for the repetitive 

inspections of certain modified or 

repaired areas only. That AD resulted 

from reports indicating new findings of 

cracks were found along the edges of the 

chem-milled pockets in the upper skin 

at certain stringers. We issued that AD 

to find and fix fatigue cracking of the 

skin panels, which could result in 

sudden fracture and failure of the skin 

panels of the fuselage, and consequent 

rapid decompression of the airplane. 

Actions Since Existing AD Was Issued 

Since we issued AD 2004–18–06, we 

have received reports of new findings of 

vertical cracks in the fuselage skin along 

the chem-milled steps adjacent to the 

butt joints and at certain body stations 

on airplanes with between 45,100 flight 

cycles (65,200 flight hours) and 67,400 

flight cycles (70,800 flight hours). 

A decompression event connected to 

chem-milled steps occurred in July 2009 

(after issuance of Boeing Alert Service 

Bulletin 737–53A1210, Revision 3, 

dated July 16, 2009) and resulted in reevaluation of the inspection thresholds 

and repetitive intervals. The new data 

and analysis require the repetitive 

intervals be reduced from those 

currently specified in Boeing Alert 

Service Bulletin 737–53A1210, Revision 

3, dated July 16, 2009. These new 

repetitive intervals are defined in the 

differences section of the NPRM. 

Explanation of Relevant Service 

Information 

We have reviewed Boeing Alert 

Service Bulletin 737–53A1210, Revision 

2, dated March 3, 2009; and Boeing 

Alert Service Bulletin 737–53A1210, 

Revision 3, dated July 16, 2009. Boeing 

Alert Service Bulletin 737–53A1210, 

Revision 1, dated October 25, 2001, was 

referred to as the appropriate source of 

service information for accomplishing 

the actions in the existing AD. 

Boeing Alert Service Bulletin 737– 

53A1210, Revision 2, describes 

procedures for, among other things, 

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12620 Federal Register / Vol. 76, No. 45 / Tuesday, March 8, 2011 / Proposed Rules 

repetitive external detailed and eddy 

current inspections for cracking of the 

fuselage skin along certain chem-milled 

lines, and corrective actions if 

necessary. The corrective actions 

include doing a time-limited repair or a 

permanent repair, as applicable. After 

installation of a time-limited repair, an 

external detailed inspection is done of 

the repaired area for cracks and loose or 

missing fasteners. For airplanes on 

which cracks are found, this service 

bulletin recommends contacting Boeing 

for repair instructions and repairing; 

and, for airplanes on which loose or 

damaged fasteners are found this service 

bulletin specifies replacing any 

damaged or loose fasteners. This service 

bulletin adds an optional preventive 

modification for Groups 3, 5, 6, and 8 

at body station (BS) 500D through BS 

520 on Model 737–300 airplanes, and 

BS 482B through BS 520, stringer 12, on 

Model 737–500 airplanes. This service 

bulletin also reduces the effectivity 

specified in Revision 1, and contains 

editorial changes. 

Boeing Alert Service Bulletin 737– 

53A1210, Revision 3, clarifies certain 

work instructions. This service bulletin 

also specifies that more work is 

necessary for airplanes on which the 

actions in Boeing Alert Service Bulletin 

737–53A1210, dated December 14, 

2000; or Revision 1, dated October 25, 

2001; were done. In addition, Revision 

3 of this service bulletin adds the 

airplanes that were incorrectly removed 

from the effectivity in Revision 2 of this 

service bulletin, which were not 

identified until after Revision 2 of this 

service bulletin was issued. Therefore, 

the effectivity in Revision 3 of this 

service bulletin is the same as the 

effectivity in Revision 1 of this service 

bulletin. 

Boeing Alert Service Bulletin 737– 

53A1210, Revision 3, specifies that the 

repetitive inspection interval is 4,500 

flight cycles. 

FAA’s Determination and Requirements 

of the Proposed AD 

We have evaluated all pertinent 

information and identified an unsafe 

condition that is likely to develop on 

other airplanes of the same type design. 

For this reason, we are proposing this 

AD, which would supersede AD 2004– 

18–06 and would retain certain 

requirements of the existing AD. This 

proposed AD would also require 

accomplishing the actions specified in 

the service information described 

previously, except as discussed under 

‘‘Differences Between the Proposed AD 

and Service Information.’’ This proposed 

AD also reduces the compliance time of 

40,000 total flight cycles for doing 

certain actions in AD 2004–18–06; this 

proposed AD specifies a compliance 

time of 35,000 total flight cycles in 

paragraph (s) of this AD. 

Differences Between the Proposed AD 

and Service Information 

Boeing Alert Service Bulletin 737– 

53A1210, Revision 3, dated July 16, 

2009, specifies to contact the 

manufacturer for disposition of certain 

repair 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) that 

we have authorized to make those 

findings. 

Boeing Alert Service Bulletin 737– 

53A1210, Revision 2, dated March 3, 

2009, specifies that no airplanes were 

added or removed from the effectivity; 

however, the manufacturer has 

informed us that there were airplanes 

incorrectly removed in the 

‘‘Identification by Customer, Customer 

Code, Group and Variable Number’’ 

section in Paragraph 1.A.1 of Revision 2 

of this service bulletin. In light of the 

fact that Revision 3 of this service 

bulletin includes those airplanes in its 

effectivity, and includes all the actions 

specified in Revision 2 of this service 

bulletin, this proposed AD would 

require that the new actions be done in 

accordance with Revision 3 of this 

service bulletin. 

Paragraph 1.E of Boeing Alert Service 

Bulletin 737–53A1210, Revision 3, 

specifies a repetitive inspection interval 

of 4,500 flight cycles; that interval is 

expected to be reduced when this 

service bulletin is revised. The 

manufacturer has informed us that it has 

re-evaluated the inspection interval 

because it would not address the 

identified unsafe condition soon enough 

to ensure an acceptable level of safety 

for the affected fleet. In light of this fact, 

we find that a repetitive inspection 

interval of 1,800 flight cycles, for the 

actions specified in Tables 1 through 5, 

represents an appropriate interval of 

time for affected airplanes to continue to 

operate without compromising safety. 

Part 8 of the Accomplishment 

Instructions of Boeing Alert Service 

Bulletin 737–53A1210, Revision 3, 

specifies a post-repair inspection of the 

skin chem-milled crack repair at stringer 

12; that inspection is not required by 

this proposed AD. The damage tolerance 

inspections specified in Table 7 of 

Boeing Alert Service Bulletin 737– 

53A1210, Revision 3, dated July 16, 

2009, may be used in support of 

compliance with section 121.1109(c)(2) 

or 129.109(c)(2) of the Federal Aviation 

Regulations (14 CFR 121.1109(c)(2) or 

14 CFR 129.109(c)(2)). 

Explanation of Change to This Proposed 

AD 

Boeing Commercial Airplanes has 

received an Organization Delegation 

Authority (ODA), which replaces their 

previous designation as a Designated 

Engineering Representative (DER). We 

have revised paragraphs (j) and (l)(2) of 

this proposed AD to delegate the 

authority to approve an alternative 

method of compliance for any repair 

required by this AD to the Boeing 

Commercial Airplanes ODA. 

Change to Existing AD 

This proposed AD would retain 

certain requirements of AD 2004–18–06. 

Since AD 2004–18–06 was issued, the 

AD format has been revised, and certain 

paragraphs have been rearranged. As a 

result, the corresponding paragraph 

identifiers have changed in this 

proposed AD, as listed in the following 

table: 

REVISED PARAGRAPH IDENTIFIERS

Requirement in AD 

2004–18–06 

Corresponding 

requirement in this 

proposed AD 

paragraph (a) paragraph (g) 

paragraph (b) paragraph (h) 

paragraph (c) paragraph (i) 

paragraph (d) paragraph (j) 

paragraph (e) paragraph (k) 

paragraph (f) paragraph (l) 

paragraph (g) paragraph (m) 

paragraph (h) paragraph (n) 

paragraph (i) paragraph (o) 

We have revised paragraph (m) of this 

proposed AD to specify that doing 

paragraph (b) or (c), as applicable, of AD 

2003–14–06, Amendment 39–13225, 

after the effective date of this proposed 

AD does not terminate any of the 

actions required by paragraph (g) of this 

proposed AD. Recent reports of cracking 

have shown that a detailed inspection 

alone is not sufficient to find cracks in 

the fuselage skin. The cracking begins 

on the internal surface of the skin and 

grows outward, not becoming visible on 

the external surface until the crack is at 

least three inches in length. Actions 

accomplished before the effective date 

of this AD in accordance with AD 2003– 

14–06, which terminate certain 

requirements of paragraph (g) of this 

proposed AD, are reinstated with the 

new requirements specified in 

paragraph (p) of this proposed AD. 

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Federal Register / Vol. 76, No. 45 / Tuesday, March 8, 2011 / Proposed Rules 12621 

Costs of Compliance 

There are about 903 airplanes of U.S. 

registry affected by AD 2004–18–06. 

The inspections of the crown area that 

are required by AD 2004–18–06 take 

about 94 work hours per airplane to 

accomplish, at an average labor rate of 

$85 per work hour. Based on these 

figures, the estimated cost of the 

currently required inspections is $7,990 

per airplane, per inspection cycle. 

The inspections of the lower lobe area 

that are required by AD 2004–18–06 

take about 96 work hours per airplane 

to accomplish, at an average labor rate 

of $85 per work hour. Based on these 

figures, the estimated cost of the 

currently required inspections is $8,160 

per airplane, per inspection cycle. 

Should an operator elect to install the 

preventive modification specified in AD 

2004–18–06 it will take about 108 work 

hours per airplane to accomplish, at an 

average labor rate of $85 per work hour. 

Based on these figures, the estimated 

cost of the modification is $9,180 per 

airplane. 

The new proposed inspections would 

affect about 701 airplanes of U.S. 

registry. 

The new proposed inspections would 

take about 27 work hours per airplane, 

at an average labor rate of $85 per work 

hour. Based on these figures, the 

estimated cost of the new actions 

specified in this proposed AD for U.S. 

operators is $1,608,795, or $2,295 per 

airplane, per inspection cycle. 

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 have 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 that the 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 

removing amendment 39–13784 (69 FR 

54206, September 8, 2004) and adding 

the following new AD: 

The Boeing Company: Docket No. FAA– 

2011–0155; Directorate Identifier 2009– 

NM–141–AD. 

Comments Due Date 

(a) The FAA must receive comments on 

this AD action by April 22, 2011. 

Affected ADs 

(b) This AD supersedes AD 2004–18–06, 

Amendment 39–13784. AD 2002–07–08, 

Amendment 39–12702; and AD 2003–14–06, 

Amendment 39–13225; affect this AD. 

Applicability 

(c) This AD applies to The Boeing 

Company Model 737–200, –200C, –300, 

–400, and –500 series airplanes, certificated 

in any category, as listed in Boeing Alert 

Service Bulletin 737–53A1210, Revision 3, 

dated July 16, 2009. 

Subject 

(d) Air Transport Association (ATA) of 

America Code 53: Fuselage. 

Unsafe Condition 

(e) This AD results from new findings of 

vertical cracks along chem-milled steps 

adjacent to the butt joints. The Federal 

Aviation Administration is issuing this AD to 

detect and correct fatigue cracking of the skin 

panels, which could result in sudden fracture 

and failure of the skin panels of the fuselage, 

and consequent rapid decompression of the 

airplane. 

Compliance 

(f) You are responsible for having the 

actions required by this AD performed within 

the compliance times specified, unless the 

actions have already been done. 

Restatement of Certain Requirements of AD 

2004–18–06, Amendment 39–13784 

External Detailed and Eddy Current 

Inspections 

(g) For Groups 1 through 5 airplanes 

identified in Boeing Alert Service Bulletin 

737–53A1210, Revision 1, dated October 25, 

2001: Before the accumulation of 35,000 total 

flight cycles, or within 4,500 flight cycles 

after October 13, 2004 (the effective date of 

AD 2004–18–06), whichever is later, do 

external detailed and eddy current 

inspections of the crown area and other 

known areas of fuselage skin cracking, per 

Part 1 and Figure 1 of the Work Instructions 

of Boeing Alert Service Bulletin 737– 

53A1210, Revision 1, dated October 25, 2001; 

or in accordance with Part 1 of the 

Accomplishment Instructions of Boeing Alert 

Service Bulletin 737–53A1210, Revision 3, 

dated July 16, 2009. As of the effective date 

of this AD, use only Boeing Alert Service 

Bulletin 737–53A1210, Revision 3, dated July 

16, 2009. Repeat the external detailed and 

eddy current inspections at intervals not to 

exceed 4,500 flight cycles until paragraph (i), 

(j)(1)(ii), (k), (l), or (m) of this AD has been 

done, as applicable. Although paragraph 1.D. 

of Boeing Alert Service Bulletin 737– 

53A1210, Revision 1, dated October 25, 2001, 

references a reporting requirement, such 

reporting is not required by this AD. 

Accomplishing the actions required by 

paragraph (p) or (q) of this AD ends the 

repetitive requirements in this paragraph. 

Note 1: For the purposes of this AD, a 

detailed inspection is defined as: ‘‘An 

intensive visual examination of a specific 

structural area, system, installation, or 

assembly to detect damage, failure, or 

irregularity. Available lighting is normally 

supplemented with a direct source of good 

lighting at intensity deemed appropriate by 

the inspector. Inspection aids such as mirror, 

magnifying lenses, etc., may be used. Surface 

cleaning and elaborate access procedures 

may be required.’’ 

(h) For all airplanes identified in Boeing 

Alert Service Bulletin 737–53A1210, 

Revision 1, dated October 25, 2001, do an 

external detailed inspection of the lower lobe 

area and section 41 of the fuselage for 

cracking, per Part 2 and Figure 2 of the Work 

Instructions of Boeing Alert Service Bulletin 

737–53A1210, Revision 1, dated October 25, 

2001; or in accordance with Part 4 of the 

Accomplishment Instructions of Boeing Alert 

Service Bulletin 737–53A1210, Revision 3, 

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12622 Federal Register / Vol. 76, No. 45 / Tuesday, March 8, 2011 / Proposed Rules 

dated July 16, 2009. As of the effective date 

of this AD, use only Boeing Alert Service 

Bulletin 737–53A1210, Revision 3, dated July 

16, 2009. At the earlier of the times specified 

in paragraphs (h)(1) and (h)(2) of this AD, do 

the inspection specified in this paragraph 

and repeat the inspection thereafter at 

intervals not to exceed 4,500 flight cycles 

until paragraph (j)(2) or (k) of this AD has 

been done, as applicable. Accomplishing the 

actions required by paragraph (s) of this AD 

ends the requirements in this paragraph. 

(1) Within 9,000 flight cycles after doing 

the most recent internal detailed inspection. 

(2) Within 4,500 flight cycles after October 

13, 2004, or before the accumulation of 

40,000 total flight cycles, whichever occurs 

later. 

Preventive Modification 

(i) For Groups 3 and 5 airplanes identified 

in Boeing Alert Service Bulletin 737– 

53A1210, Revision 1, dated October 25, 2001: 

If no cracking is found during any inspection 

required by paragraph (g) of this AD, doing 

the preventive modification of the chemmilled pockets in the upper skin as specified 

in Part 5 of the Work Instructions of Boeing 

Alert Service Bulletin 737–53A1210, 

Revision 1, dated October 25, 2001; or as 

specified in Part 7 of the Work Instructions 

of Boeing Alert Service Bulletin 737– 

53A1210, Revision 3, dated July 16, 2009, 

except as required by paragraph (x) of this 

AD; ends the repetitive external detailed and 

eddy current inspections required by 

paragraph (g) of this AD for the modified area 

only. As of the effective date of this AD, use 

only Boeing Alert Service Bulletin 737– 

53A1210, Revision 3, dated July 16, 2009. 

Corrective Actions 

(j) If any cracking is found during any 

inspection required by paragraph (g), (h), (p), 

(q), or (s) of this AD, before further flight, do 

the actions specified in paragraphs (j)(1) and 

(j)(2) of this AD, as applicable, in accordance 

with the Work Instructions of Boeing Alert 

Service Bulletin 737–53A1210, Revision 1, 

dated October 25, 2001; or Revision 3, dated 

July 16, 2009. As of the effective date of this 

AD, use only Boeing Alert Service Bulletin 

737–53A1210, Revision 3, dated July 16, 

2009. Where Boeing Alert Service Bulletin 

737–53A1210, Revision 1, dated October 25, 

2001; or Revision 3, dated July 16, 2009; 

specify to contact Boeing for repair 

instructions, before further flight, repair per 

a method approved by the Manager, Seattle 

Aircraft Certification Office (ACO), FAA; or 

per data meeting the type certification basis 

of the airplane if it is approved by the Boeing 

Commercial Airplanes Organization 

Designation Authorization (ODA) or any 

other person authorized by the Manager, 

Seattle 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. 

(1) Except as provided by paragraph (k) of 

this AD, for cracking of the crown area, do 

the repair specified in either paragraph 

(j)(1)(i) or (j)(1)(ii) of this AD. 

(i) Do a time-limited repair per Part 4 of the 

Work Instructions of Boeing Alert Service 

Bulletin 737–53A1210, Revision 1, dated 

October 25, 2001; or in accordance with Part 

6 of the Work Instructions of Boeing Alert 

Service Bulletin 737–53A1210, Revision 3, 

dated July 16, 2009, except as required by 

paragraph (x) of this AD, then do the actions 

required by paragraph (l) of this AD at the 

times specified in that paragraph. 

(ii) Do a permanent repair per Part 3 of the 

Work Instructions of Boeing Alert Service 

Bulletin 737–53A1210, Revision 1, dated 

October 25, 2001; or in accordance with Part 

5 of the Work Instructions of Boeing Alert 

Service Bulletin 737–53A1210, Revision 3, 

dated July 16, 2009. Installation of a 

permanent repair ends the repetitive 

inspections required by paragraph (g) of this 

AD for the repaired area only. Installation of 

the lap joint repair specified in paragraph (g) 

of AD 2002–07–08, Amendment 39–12702, is 

considered acceptable for compliance with 

the corresponding permanent repair specified 

in this paragraph for the repaired areas only. 

(2) Except as provided by paragraph (k) of 

this AD, for cracking of the lower lobe area 

and Section 41, repair per Part 2 of the Work 

Instructions of Boeing Alert Service Bulletin 

737–53A1210, Revision 1, dated October 25, 

2001; or in accordance with paragraph 

(j)(2)(i) or (j)(2)(ii) of this AD. 

Accomplishment of this repair ends the 

repetitive inspections required by paragraph 

(h) of this AD for the repaired area only. As 

of the effective date of this, do the repair 

specified in paragraph (j)(2)(i) or (j)(2)(ii) of 

this AD. 

(i) Do a time-limited repair in accordance 

with Part 6 of the Work Instructions of 

Boeing Alert Service Bulletin 737–53A1210, 

Revision 3, dated July 16, 2009, except as 

required by paragraph (x) of this AD, then do 

the actions required by paragraph (l) of this 

AD at the times specified in that paragraph. 

(ii) Do a permanent repair in accordance 

with Part 5 of the Accomplishment 

Instructions of Boeing Alert Service Bulletin 

737–53A1210, Revision 3, dated July 16, 

2009. 

Optional Repair Method 

(k) For cracking in any area specified in 

paragraphs (j)(1) and (j)(2) of this AD within 

the limitations of the applicable structural 

repair manual (SRM) specified in table 1 of 

this AD, repair any cracks per the applicable 

SRM specified in table 1 of this AD. 

Accomplishment of the applicable repair 

terminates the repetitive inspections required 

by paragraphs (g) and (h) of this AD for the 

repaired area only. 

TABLE 1—SRM REFERENCES

Model Subject/figure Revision Date SRM 

737–100, –200 series airplanes ........... 53–30–3, Figure 48 ....... 102 September 10, 2010 Boeing 737–100/–200 SRM, D6– 

15565. 

737–300 series airplanes ..................... 53–00–01, Figure 229 ... 92 November 10, 2010 .. Boeing 737–300 SRM D6–37635. 

737–400 series airplanes ..................... 53–00–01, Figure 231 ... 75 November 10, 2010 .. Boeing 737–400 SRM, D6–38246. 

737–500 series airplanes ..................... 53–00–01, Figure 229 ... 70 November 10, 2010 .. Boeing 737–500 SRM, D6–38441. 

Follow-on and Corrective Actions 

(l) If a time-limited repair is done, as 

specified in paragraph (j)(1)(i) or (j)(2)(i) of 

this AD: Do the actions specified in 

paragraphs (l)(1), (l)(2), and (l)(3) of this AD, 

at the times specified in paragraphs (l)(1), 

(l)(2), and (l)(3) of this AD, per the Work 

Instructions of Boeing Alert Service Bulletin 

737–53A1210, Revision 1, dated October 25, 

2001; or Boeing Alert Service Bulletin 737– 

53A1210, Revision 3, dated July 16, 2009. 

(1) Within 3,000 flight cycles after doing 

the repair: Do the actions specified in 

paragraph (l)(1)(i) or (l)(1)(ii) of this AD. 

Then repeat the applicable inspection 

specified in paragraph (l)(1)(i) or (l)(1)(ii) of 

this AD at intervals not to exceed 3,000 flight 

cycles until permanent rivets are installed in 

the repaired area, which ends the repetitive 

inspections for this paragraph. As of the 

effective date of this AD, do only the 

inspections specified in paragraph (l)(1)(ii) of 

this AD. 

(i) For repairs done before the effective 

date of this AD: Do a detailed inspection of 

the repaired area for loose fasteners per Part 

4 of the Work Instructions of Boeing Alert 

Service Bulletin 737–53A1210, Revision 1, 

dated October 25, 2001, or do the actions 

specified in paragraph (l)(1)(ii) of this AD. If 

any loose fastener is found, before further 

flight, replace with a new fastener per Boeing 

Alert Service Bulletin 737–53A1210, 

Revision 1, dated October 25, 2001. 

(ii) For repairs done after the effective date 

of this AD: Do a detailed inspection of the 

repaired area for loose, damaged, and missing 

fasteners in accordance with Part 6 of the 

Accomplishment Instructions of Boeing Alert 

Service Bulletin 737–53A1210, Revision 3, 

dated July 16, 2009. If any loose, missing, or 

damaged fastener is found, before further 

flight, replace with a new fastener in 

accordance with Boeing Alert Service 

Bulletin 737–53A1210, Revision 3, dated July 

16, 2009. 

(2) At the applicable time specified in 

paragraph (l)(2)(i) and (l)(2)(ii) of this AD: Do 

inspections of the repaired area for cracking 

per Part 4 of the Work Instructions of Boeing 

Alert Service Bulletin 737–53A1210, 

Revision 1, dated October 25, 2001; or in 

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accordance with Part 6 of the Work 

Instructions of Boeing Alert Service Bulletin 

737–53A1210, Revision 3, dated July 16, 

2009. If any cracking is found, before further 

flight, repair per a method approved by the 

Manager, Seattle ACO, or per data meeting 

the type certification basis of the airplane if 

it is approved by the Boeing Commercial 

Airplanes ODA or any other person 

authorized by the Manager, Seattle 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. 

(i) For repairs done before the effective 

date of this AD: Within 4,000 flight cycles 

after doing the repair, do the inspections. 

(ii) For repairs done on or after the 

effective date of this AD: Within 3,000 flight 

cycles after doing the repair, do the 

inspections. 

(3) At the earlier of the times specified in 

paragraphs (l)(3)(i) and (l)(3)(ii) of this AD: 

Make the repair permanent per Part 4 and 

Figure 20 of the Work Instructions of Boeing 

Alert Service Bulletin 737–53A1210, 

Revision 1, dated October 25, 2001, or do the 

permanent repair in accordance with Part 5 

of the Work Instructions of Boeing Alert 

Service Bulletin 737–53A1210, Revision 3, 

dated July 16, 2009, which ends the 

repetitive inspections for the repaired area 

only. As of the effective date of this AD, 

make the repair permanent in accordance 

with Boeing Alert Service Bulletin 737– 

53A1210, Revision 3, dated July 16, 2009. 

(i) Within 10,000 flight cycles after doing 

the repair in accordance with Boeing Alert 

Service Bulletin 737–53A1210, Revision 1, 

dated October 25, 2001. 

(ii) At the later of the times specified in 

paragraphs (l)(3)(ii)(A) and (l)(3)(ii)(B) of this 

AD. 

(A) Within 6,000 flight cycles after doing 

the repair. 

(B) Within 1,000 flight cycles after the 

effective date of this AD. 

Optional Terminating Action for Repetitive 

Eddy Current Inspections if Done Before the 

Effective Date of This AD 

(m) Accomplishment of paragraph (b) or 

(c), as applicable, of AD 2003–14–06, 

Amendment 39–13225, before the effective 

date of this AD ends the repetitive eddy 

current inspections required by paragraph (g) 

of this AD for that skin panel only; however, 

the repetitive external detailed inspections 

required by paragraph (g) of this AD are still 

required for all areas. As of the effective date 

of this AD, accomplishing paragraph (b) or 

(c), as applicable, of AD 2003–14–06, 

Amendment 39–13225, does not end the 

repetitive eddy current inspections required 

by paragraph (g) of this AD. 

Credit for Actions Done per Previous Service 

Bulletin 

(n) Inspections, repairs, and preventive 

modifications done before October 13, 2004, 

in accordance with Boeing Alert Service 

Bulletin 737–53A1210, dated December 14, 

2000, are acceptable for compliance with the 

corresponding actions required by 

paragraphs (g), (h), (i), (j), (k), and (l) of this 

AD. 

Exception to Service Bulletin Procedures 

(o) For airplanes subject to the 

requirements of paragraphs (g), (h), (p), and 

(q) of this AD: Inspections are not required 

in areas that are spanned by an FAAapproved repair that has a minimum of 3 

rows of fasteners above and below the chemmilled step. If an external doubler covers the 

chem-milled step, but does not span it by a 

minimum of 3 rows of fasteners above and 

below, in lieu of requesting approval for an 

alternative method of compliance (AMOC), 

one option to comply with the inspection 

requirement of paragraphs (g) and (h) of this 

AD is to inspect all chem-milled steps 

covered by the repair using internal 

nondestructive test (NDT) methods in 

accordance with Part 6 of the Boeing 737 

Non-Destructive Test NDT Manual. As of the 

effective date of this AD, inspect in 

accordance with Boeing Alert Service 

Bulletin 737–53A1210, Revision 3, dated July 

16, 2009. 

New Requirements of This AD 

Repetitive Inspections and Corrective Actions 

if Necessary 

(p) For Groups 1 through 5 and 9 through 

21 airplanes identified in Boeing Alert 

Service Bulletin 737–53A1210, Revision 3, 

dated July 16, 2009, on which the inspections 

required by paragraph (g) of this AD have 

been done before the effective date of this 

AD: At the applicable time specified in 

paragraph (p)(1) or (p)(2) of this AD, do 

external detailed and eddy current 

inspections of the crown area and other 

known areas of fuselage skin cracking in 

accordance with Part 1 of the 

Accomplishment Instructions of Boeing Alert 

Service Bulletin 737–53A1210, Revision 3, 

dated July 16, 2009; except as provided by 

paragraph (o) of this AD. Repeat the external 

detailed and eddy current inspections 

thereafter at intervals not to exceed 1,800 

flight cycles. Accomplishing the inspections 

required by this paragraph ends the repetitive 

inspections required by paragraph (g) of this 

AD. Before further flight, do all applicable 

corrective actions as specified in paragraph 

(j) of this AD. 

(1) For airplanes on which any action 

specified in paragraph (i), (j)(1)(ii), (k), (l), or 

(m) of this AD has been done: Within 1,800 

flight cycles after the effective date of this 

AD. 

(2) For airplanes on which actions 

specified in paragraphs (i), (j)(1)(ii), (k), (l), 

and (m) of this AD have not been done: 

Within 4,500 flight cycles after doing the 

most recent inspection required by paragraph 

(g) of this AD, or within 1,800 flight cycles 

after the effective date of this AD, whichever 

is later. 

(q) For Groups 1 through 5 and 9 through 

21 airplanes identified in Boeing Alert 

Service Bulletin 737–53A1210, Revision 3, 

dated July 16, 2009; on which the inspections 

required by paragraph (g) of this AD have not 

been done before the effective date of this 

AD: Before the accumulation of 35,000 total 

flight cycles, or within 1,800 flight cycles 

after the effective date of this AD, whichever 

is later, do external detailed and eddy current 

inspections of the crown area and other 

known areas of fuselage skin cracking in 

accordance with Part 1 of the 

Accomplishment Instructions of Boeing Alert 

Service Bulletin 737–53A1210, Revision 3, 

dated July 16, 2009. Repeat the external 

detailed and eddy current inspections 

thereafter at intervals not to exceed 1,800 

flight cycles. Before further flight, do all 

applicable corrective actions as specified in 

paragraph (j) of this AD. 

(r) For Group 1 through 5 and 9 through 

21 airplanes identified in Boeing Alert 

Service Bulletin 737–53A1210, Revision 3, 

dated July 16, 2009: At the later of the times 

specified in paragraphs (r)(1) and (r)(2) of this 

AD, do external detailed and eddy current 

inspections for vertical cracks in the fuselage 

skin along the chem-milled steps of the butt 

joints, in accordance with Part 3 of the 

Accomplishment Instructions of Boeing Alert 

Service Bulletin 737–53A1210, Revision 3, 

dated July 16, 2009. Repeat the inspections 

thereafter at intervals not to exceed 1,800 

flight cycles or 1,800 flight hours, whichever 

occurs first. If any cracking is found, before 

further flight, repair in accordance with Part 

5 of the Accomplishment Instructions of 

Boeing Alert Service Bulletin 737–53A1210, 

Revision 3, dated July 16, 2009. Doing the 

repair terminates the repetitive inspections 

specified in this paragraph for the repaired 

area only. 

(1) Before the accumulation of 55,000 total 

flight cycles or 55,000 total flight hours, 

whichever occurs first. 

(2) Within 1,800 flight cycles or 1,800 

flight hours after the effective date of this AD, 

whichever occurs first. 

(s) For Groups 1 through 21 airplanes 

identified in Boeing Alert Service Bulletin 

737–53A1210, Revision 3, dated July 16, 

2009: Before the accumulation of 35,000 total 

flight cycles or within 4,500 flight cycles 

after the effective date of this AD, whichever 

is later, do external detailed and eddy current 

inspections for horizontal cracks along the 

chem-milled lines of the fuselage skin of the 

lower lobe area and section 41, in accordance 

with Part 4 of the Accomplishment 

Instructions of Boeing Alert Service Bulletin 

737–53A1210, Revision 3, dated July 16, 

2009; except as required by paragraph (u) of 

this AD. Repeat the inspections thereafter at 

intervals not to exceed 4,500 flight cycles. 

Accomplishing the inspections required by 

this paragraph ends the repetitive inspections 

required by paragraph (h) of this AD. Before 

further flight, do all applicable corrective 

actions as specified in paragraph (j) of this 

AD. 

(t) For Groups 4, 11, and 16 airplanes 

identified in Boeing Alert Service Bulletin 

737–53A1210, Revision 3, dated July 16, 

2009: Before the accumulation of 25,000 total 

flight cycles or within 4,500 flight cycles 

after the effective date of this AD, whichever 

is later, do external detailed and eddy current 

inspections for horizontal cracks along the 

chem-milled lines of the fuselage skin of the 

fuselage window belt area in accordance with 

Part 2 of the Accomplishment Instructions of 

Boeing Alert Service Bulletin 737–53A1210, 

Revision 3, dated July 16, 2009. Repeat the 

inspections thereafter at intervals not to 

exceed 4,500 flight cycles. If any cracking is 

found, before further flight, repair using a 

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method approved in accordance with 

paragraph (y) of this AD. 

(u) For Groups 3, 5, 9, 10, 12, 14, 15, 17, 

18, 19, 20, and 21 airplanes identified in 

Boeing Alert Service Bulletin 737–53A1210, 

Revision 3, dated July 16, 2009: Do the 

actions specified in paragraph (u)(1) or (u)(2) 

of this AD, as applicable. 

(1) For airplanes on which the inspections 

required by paragraph (g) of this AD have 

been done before the effective date of this 

AD: Within 4,500 flight cycles after doing the 

most recent inspection required by paragraph 

(g) of this AD, do external detailed and eddy 

current inspections for horizontal cracks 

along the chem-milled lines of the fuselage 

skin of the fuselage window belt area in 

accordance with Part 2 of the 

Accomplishment Instructions of Boeing Alert 

Service Bulletin 737–53A1210, Revision 3, 

dated July 16, 2009. Repeat the inspections 

thereafter at intervals not to exceed 4,500 

flight cycles. If any cracking is found, before 

further flight, repair in accordance with Part 

8 of Boeing Alert Service Bulletin 737– 

53A1210, Revision 3, dated July 16, 2009, 

except as required by paragraph (x) of this 

AD. 

(2) For airplanes on which the inspections 

required by paragraph (g) of this AD have not 

been done before the effective date of this 

AD: Before the accumulation of 25,000 total 

flight cycles or within 4,500 flight cycles 

after the effective date of this AD, whichever 

is later, do external detailed and eddy current 

inspections for horizontal cracks along the 

chem-milled lines of the fuselage skin of the 

fuselage window belt area in accordance with 

Part 2 of the Accomplishment Instructions of 

Boeing Alert Service Bulletin 737–53A1210, 

Revision 3, dated July 16, 2009. Repeat the 

inspections thereafter at intervals not to 

exceed 4,500 flight cycles. If any cracking is 

found, before further flight, repair in 

accordance with Part 8 of Boeing Alert 

Service Bulletin 737–53A1210, Revision 3, 

dated July 16, 2009, except as required by 

paragraph (x) of this AD. 

Repair and Preventive Modification 

(v) For airplanes on which cracking is 

found during any inspection required by 

paragraph (p), (q), (r), or (s) of this AD, as 

applicable, doing the repair of the chemmilled area in the skin, as specified in Part 

5 or Part 6 of the Accomplishment 

Instructions of Boeing Alert Service Bulletin 

737–53A1210, Revision 3, dated July 16, 

2009, ends the repetitive external detailed 

and eddy current inspections required by 

paragraph (p), (q), (r), or (s) of this AD, as 

applicable, for the repaired area only. 

Note 2: Part 8 of the Accomplishment 

Instructions of Boeing Alert Service Bulletin 

737–53A1210, Revision 3, dated July 16, 

2009, specifies a post-repair inspection of the 

skin chem-milled crack repair at stringer 12; 

that inspection is not required by this AD. 

The damage tolerance inspections specified 

in Table 7 of Boeing Alert Service Bulletin 

737–53A1210, Revision 3, dated July 16, 

2009, may be used in support of compliance 

with section 121.1109(c)(2) or 129.109(c)(2) 

of the Code of Federal Regulations (14 CFR 

121.1109(c)(2) or 14 CFR 129.109(c)(2)). 

(w) For airplanes on which no cracking is 

found during any inspection required by 

paragraph (p) or (q) of this AD, as applicable, 

doing the preventive modification of the 

chem-milled areas in the skin at stringer 

S–12, as specified in Part 7 of the 

Accomplishment Instructions of Boeing Alert 

Service Bulletin 737–53A1210, Revision 3, 

dated July 16, 2009, except as required by 

paragraph (x) of this AD, ends the repetitive 

external detailed and eddy current 

inspections required by paragraph (p) or (q) 

of this AD, as applicable, for the modified 

area only. 

Exception to Boeing Alert Service Bulletin 

737–53A1210, Revision 3 

(x) Where Boeing Alert Service Bulletin 

737–53A1210, Revision 3, dated July 16, 

2009, specifies to contact Boeing for repair 

instructions, before further flight, repair 

using a method approved in accordance with 

paragraph (y) of this AD. 

Alternative Methods of Compliance 

(AMOCs) 

(y)(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 e-mailed 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 repair 

required by this AD if it is approved by the 

Boeing Commercial Airplanes ODA that has 

been authorized by the Manager, Seattle 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. 

(4) AMOCs approved previously in 

accordance with AD 2004–18–06, 

Amendment 39–13784, are approved as 

AMOCs for the corresponding provisions of 

this AD. 

Related Information 

(z) For more information about this AD, 

contact Wayne Lockett, Aerospace Engineer, 

Airframe Branch, ANM–120S, FAA, Seattle 

Aircraft Certification Office, 1601 Lind 

Avenue, SW., Renton, Washington 98057– 

3356; telephone (425) 917–6447; fax (425) 

917–6590; e-mail: wayne.lockett@faa.gov. 

Issued in Renton, Washington on February 

22, 2011. 

Kalene C. Yanamura, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service. 

[FR Doc. 2011–5159 Filed 3–7–11; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2011–0152; Directorate 

Identifier 2010–NM–079–AD] 

RIN 2120–AA64 

Airworthiness Directives; DassaultAviation Model FALCON 7X Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: We propose to adopt a new 

airworthiness directive (AD) for the 

products listed above. This proposed 

AD results from mandatory continuing 

airworthiness information (MCAI) 

originated by an aviation authority of 

another country to identify and correct 

an unsafe condition on an aviation 

product. The MCAI describes the unsafe 

condition as: 

On some Falcon 7X aeroplanes, it has been 

determined potential low clearance between 

electrical wiring or hydraulic pipe and 

nearby structure. Although no in service 

incident has been reported, there is no 

certainty that the minimum clearances would 

be maintained over time. In the worst case, 

interference or contact with structure might 

occur and lead to electrical short circuits or 

fluid leakage, potentially resulting in loss of 

several functions essential for safe flight. 

* * * * * 

The proposed AD would require 

actions that are intended to address the 

unsafe condition described in the MCAI. 

DATES: We must receive comments on 

this proposed AD by April 22, 2011. 

ADDRESSES: You may send comments by 

any of the following methods: 

• Federal eRulemaking Portal: Go to 

http://www.regulations.gov. Follow the 

instructions for submitting comments. 

• Fax: (202) 493–2251. 

• Mail: U.S. Department of 

Transportation, Docket Operations, 

M–30, West Building Ground Floor, 

Room W12–140, 1200 New Jersey 

Avenue SE., Washington, DC 20590. 

• Hand Delivery: U.S. Department of 

Transportation, Docket Operations, 

M–30, West Building Ground Floor, 

Room W12–40, 1200 New Jersey 

Avenue SE., Washington, DC, between 9 

a.m. and 5 p.m., Monday through 

Friday, except Federal holidays. 

For service information identified in 

this proposed AD, contact Dassault 

Falcon Jet, P.O. Box 2000, South 

Hackensack, New Jersey 07606; 

telephone 201–440–6700; Internet 

http://www.dassaultfalcon.com. You 

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