7486 Federal Register / Vol. 73, No. 27 / Friday, February 8, 2008 / Proposed Rules 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2008–0148; Directorate 

Identifier 2007–NM–299–AD] 

RIN 2120–AA64 

Airworthiness Directives; Boeing 

Model 747 Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: We propose to adopt a new 

airworthiness directive (AD) for all 

Boeing Model 747 airplanes. This 

proposed AD would require a one-time 

inspection of certain fuselage skins at 

section 41 to find any external doublers 

that cover the inspection areas and to 

identify the external doublers that end 

on a stringer and those that do not, and 

related investigative and corrective 

actions if necessary. This proposed AD 

results from reports of cracks found at 

fastener locations in the fuselage skins 

at section 41. We are proposing this AD 

to detect and correct fuselage skin 

cracks at fastener locations along the 

skin-to-stringer attachments, which 

could join together and become large 

and consequently result in rapid 

decompression of the cabin. 

DATES: We must receive comments on 

this proposed AD by March 24, 2008. 

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 AD, contact Boeing Commercial 

Airplanes, P.O. Box 3707, Seattle, 

Washington 98124–2207. 

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: Ivan 

Li, Aerospace Engineer, Airframe 

Branch, ANM–120S, FAA, Seattle 

Aircraft Certification Office, 1601 Lind 

Avenue, SW., Renton, Washington 

98057–3356; telephone (425) 917–6437; 

fax (425) 917–6590. 

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–2008–0148; Directorate Identifier 

2007–NM–299–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 two reports of 

cracks found at fastener locations in the 

fuselage skins at section 41. One 

operator reported finding skin cracks at 

a fastener location at stringer 5 (S–5) 

near station (STA) 365, on a Model 747–

200F series airplane. These cracks were 

found during incorporation of the skin 

modification specified in Boeing Service 

Bulletin 747–53–2272. The cracks were 

0.25 inch long and located on the 

forward and aft side of the fastener hole. 

The airplane had accumulated 13,726 

total flight cycles. In the other report, 

multiple skin cracks were found during 

Boeing Model 747–400 series airplane 

fatigue testing. That test article had 

accumulated 40,000 test cycles. The 

cracks were found at locations where 

there are no internal doublers, at 

stringers 10 and 13, and between STA 

260 and STA 300. Fuselage skin cracks 

at fastener locations along the skin-tostringer attachments, if not corrected, 

could join together and become large 

and consequently result in rapid 

decompression of the cabin. 

Relevant Service Information 

We have reviewed Boeing Alert 

Service Bulletin 747–53A2704, dated 

October 4, 2007. The service bulletin 

describes procedures for doing a onetime general visual inspection of certain 

fuselage skins at section 41 to find any 

external doublers that cover the 

inspection area and to identify the 

external doublers that end on a stringer 

and those that do not; and related 

investigative and corrective actions if 

necessary. The related investigative 

actions include the following: 

• Removing any external doubler and 

doing a one-time detailed inspection 

and an open-hole high frequency eddy 

current (HFEC) inspection for any crack 

in the skin at the skin-to-stringer 

attachments, for an inspection area 

where the skin-to-stringer attachment is 

covered by an external doubler that 

ends on a stringer in the inspection area. 

• Doing repetitive external HFEC 

inspections for any crack in the skin at 

the skin-to-stringer attachments, for an 

inspection area where the skin-tostringer attachment is not covered by an 

external doubler. 

For the one-time general visual 

inspection, one-time detailed 

inspection, one-time open-hole HFEC 

inspection, and the initial external 

HFEC inspection, the service bulletin 

specifies a compliance time of 16,000 or 

25,000 total flight cycles depending on 

the airplane configuration, or 2,000 

flight cycles after the date on the service 

bulletin, whichever occurs later. The 

service bulletin also specifies that if a 

skin panel was replaced, the inspection 

threshold for the affected area can be 

calculated from the time it was 

replaced. For the repetitive external 

HFEC inspections, the service bulletin 

specifies a repeat interval of 3,000 flight 

cycles. 

The corrective actions include 

repairing any crack found in an 

inspection area, and installing a new 

external doubler where any external 

doubler has been removed from the 

inspection area. The service bulletin 

specifies accomplishing the corrective 

actions before further flight. 

FAA’s Determination and Requirements 

of This Proposed AD 

We are proposing this AD because we 

evaluated all relevant information and 

determined the unsafe condition 

described previously is likely to exist or 

develop in other products of the(se) 

same type design(s). This proposed AD 

would require accomplishing the 

actions specified in the service 


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Federal Register / Vol. 73, No. 27 / Friday, February 8, 2008 / Proposed Rules 7487 

information described previously, 

except as discussed under ‘‘Differences 

Between the Proposed AD and Service 

Bulletin.’’

Differences Between Proposed AD and 

Service Bulletin 

Although Figure 19 of the service 

bulletin specifies doing a ‘‘detailed 

visual inspection’’ of the fastener holes, 

this proposed AD would require doing 

a ‘‘detailed inspection.’’

This proposed AD expands the 

inspection area at certain skin-tostringer attachments. In Figure 3 of the 

service bulletin, S–5 and S–5A from 

STA 340 to STA 360 should be bold in 

the illustration to include those areas as 

part of the recommended inspection 

(similar to Figure 8 for the right side). 

Also, in Figure 15 of the service 

bulletin, S–14A from STA 200 to STA 

220 should be bold in the illustration to 

include that area as part of the 

recommended inspection (similar to 

Figure 17 for the right side). Boeing is 

aware of these discrepancies, concurs 

with the changes, and has issued 

Information Notice (IN) 747–53A2704 

IN 01, dated December 19, 2007, to 

inform operators of the errors. We have 

included this information in paragraph 

(g) of this proposed AD. 

Clarification of Proposed Requirements 

The service bulletin notes that, at 

locations where external doublers exist 

that do not end on a stringer in the 

inspection area, repetitive inspections of 

the skin for cracking at critical rows of 

fasteners are required in accordance 

with Boeing Document Number D6–

36181, ‘‘Repair Assessment 

Guidelines—Model 747.’’ These 

inspections would not be required by 

this AD, since compliance is already 

required by sections 91.410, 121.370, 

125.248, and 129.32 of the Federal 

Aviation Regulations (14 CFR 91.410, 

121.370, 125.248, and 129.32). 

Costs of Compliance 

We estimate that this proposed AD 

would affect 165 airplanes of U.S. 

registry. We also estimate that it would 

take up to 64 work-hours per product to 

comply with this proposed AD. The 

average labor rate is $80 per work-hour. 

Based on these figures, we estimate the 

cost of this proposed AD to the U.S. 

operators to be $844,800 or $5,120 per 

product. 

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), and 

3. 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. 

You can find our regulatory 

evaluation and the estimated costs of 

compliance in the AD Docket. 

List of Subjects in 14 CFR Part 39 

Air transportation, Aircraft, Aviation 

safety, 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 AD: 

Boeing: Docket No. FAA–2008–0148; 

Directorate Identifier 2007–NM–299–AD. 

Comments Due Date 

(a) We must receive comments by March 

24, 2008. 

Affected ADs 

(b) None. 

Applicability 

(c) This AD applies to all Boeing Model 

747–100, 747–100B, 747–100B SUD, 747–

200B, 747–200C, 747–200F, 747–300, 747–

400, 747–400D, 747–400F, 747SR, and 747SP 

series airplanes, certificated in any category. 

Unsafe Condition 

(d) This AD results from reports of cracks 

found at fastener locations in the fuselage 

skins at section 41. We are issuing this AD 

to detect and correct fuselage skin cracks at 

fastener locations along the skin-to-stringer 

attachments, which could join together and 

become large and consequently result in 

rapid decompression of the cabin. 

Compliance 

(e) Comply with this AD within the 

compliance times specified, unless already 

done. 

Repetitive Inspections and Related 

Investigative/Corrective Actions 

(f) At the applicable compliance times 

specified in Tables 1 and 2 of paragraph 1.E. 

of Boeing Alert Service Bulletin 747–

53A2704, dated October 4, 2007: Do a general 

visual inspection of the fuselage skins at 

section 41 to find any external doublers that 

cover the inspection area and to identify the 

external doublers that end on a stringer in the 

inspection area and those that do not, and do 

all the related investigative and corrective 

actions as applicable, by accomplishing all of 

the applicable actions specified in the 

Accomplishment Instructions of the service 

bulletin, except as provided by paragraph (g) 

of this AD. Repeat the related investigative 

actions thereafter at the interval specified in 

Tables 1 and 2 of the service bulletin, as 

applicable. 

Exceptions to the Service Bulletin 

(g) Where Tables 1 and 2 of paragraph 1.E. 

of Boeing Alert Service Bulletin 747–

53A2704, dated October 4, 2007, specify 

counting the compliance time from ‘‘* * * 

after the date on this service bulletin,’’ this 

AD requires counting the compliance time 

from the effective date of this AD. Where 

Figure 19 of the service bulletin specifies 

doing a ‘‘detailed visual inspection’’ for any 

crack at fastener holes common to the 

stringer, this AD would require doing a 

detailed inspection. In Figure 3 of the service 

bulletin, also inspect the areas at stringer 5 

(S–5) and S–5A between station (STA) 340 

and STA 360 (similar to Figure 8 for the right 

side). In Figure 15 of the service bulletin, also 

inspect the area at S–14A between STA 200 

and STA 220 (similar to Figure 17 for the 

right side). 

Alternative Methods of Compliance 

(AMOCs) 

(h)(1) The Manager, Seattle Aircraft 

Certification Office, FAA, ATTN: Ivan Li, 

Aerospace Engineer, Airframe Branch, ANM–

120S, 1601 Lind Avenue, SW., Renton, 


ebenthall on PRODPC61 with PROPOSALS
7488 Federal Register / Vol. 73, No. 27 / Friday, February 8, 2008 / Proposed Rules 

Washington 98057–3356; telephone (425) 

917–6437; fax (425) 917–6590; has the 

authority to approve AMOCs for this AD, if 

requested using the procedures found in 14 

CFR 39.19. 

(2) To request a different method of 

compliance or a different compliance time 

for this AD, follow the procedures in 14 CFR 

39.19. Before using any approved AMOC on 

any airplane to which the AMOC applies, 

notify your appropriate principal inspector 

(PI) in the FAA Flight Standards District 

Office (FSDO), or lacking a PI, your local 

FSDO. 

(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 an 

Authorized Representative for the Boeing 

Commercial Airplanes Delegation Option 

Authorization Organization who 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. 

Issued in Renton, Washington, on January 

31, 2008. 

Ali Bahrami, 

Manager, Transport Airplane Directorate, 

Aircraft Certification Service. 

[FR Doc. E8–2352 Filed 2–7–08; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2008–0149; Directorate 

Identifier 2007–NM–319–AD] 

RIN 2120–AA64 

Airworthiness Directives; Boeing 

Model 737–100, –200, –200C, –300, 

–400, and –500 Series 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 

Boeing Model 737–100, –200, –200C, 

–300, –400, and –500 series airplanes. 

This proposed AD would require 

replacing the existing straight-to-90- 

degree hose assembly for the Lavatory 

‘‘A’’ water supply. The replacement is a 

new straight hose assembly and a 

separate 90-degree elbow fitting. This 

proposed AD results from a report of a 

separated hose assembly for the 

passenger water system. We are 

proposing this AD to prevent a water 

leak into the flight deck ceiling, which 

could result in an electrical short and 

possible loss of several functions 

essential to safe flight. 

DATES: We must receive comments on 

this proposed AD by March 24, 2008. 

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 AD, contact Boeing Commercial 

Airplanes, P.O. Box 3707, Seattle, 

Washington 98124–2207. 

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: 

Marcia Smith, Aerospace Engineer, 

Cabin Safety and Environmental 

Systems Branch, ANM–150S, FAA, 

Seattle Aircraft Certification Office, 

1601 Lind Avenue, SW., Renton, 

Washington 98057–3356; telephone 

(425) 917–6484; fax (425) 917–6590. 

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–2008–0149; Directorate Identifier 

2007–NM–319–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 a report of a 

separated hose assembly for the 

passenger water system. The hose 

assembly supplies potable water 

through a 90-degree end fitting to 

Lavatory ‘‘A.’’ The break occurred at the 

90-degree end fitting when the elbow 

separated at a soldered joint adjacent to 

the hose assembly sleeve. The break was 

located just above and inside the flight 

deck entry door, and resulted in water 

spilling into the flight deck ceiling, 

which affected various radios and the 

Aircraft Communications Addressing 

and Reporting System (ACARS) and 

caused them to become inoperative. 

These affected parts had to be replaced 

due to water damage. An analysis of the 

broken hose assembly showed signs of 

previous small leaks. It was concluded 

that an incompletely soldered joint 

failed and consequently separated. A 

broken hose assembly in this location, if 

not corrected, could leak into the flight 

deck ceiling and result in an electrical 

short and possible loss of several 

functions essential to safe flight. 

Relevant Service Information 

We have reviewed Boeing Alert 

Service Bulletin 737–38A1054, dated 

August 23, 2007. The service bulletin 

describes procedures for replacing the 

existing straight-to-90-degree hose 

assembly for the Lavatory ‘‘A’’ water 

supply. The replacement is a new 

straight hose assembly and a separate 

90-degree elbow fitting. 

FAA’s Determination and Requirements 

of This Proposed AD 

We are proposing this AD because we 

evaluated all relevant information and 

determined the unsafe condition 

described previously is likely to exist or 

develop in other airplanes of the same 

type design. This proposed AD would 

require accomplishing the actions 

specified in the service information 

described previously. 

Costs of Compliance 

We estimate that this proposed AD 

would affect 779 airplanes of U.S. 

registry. We also estimate that it would 

take between 4 and 7 work-hours per 

airplane to comply with this proposed 

AD, depending on the airplane 

configuration. The average labor rate is 

$80 per work-hour. Required parts 

would cost about $400 per product. 

Based on these figures, we estimate the 


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