Federal Register / Vol. 67, No. 1 / Wednesday, January 2, 2002 / Proposed Rules 35

39 of the Federal Aviation Regulations 

(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. Section 39.13 is amended by 

adding the following new airworthiness 

directive:

Dassault Aviation: Docket 2000–NM–335–

AD.

Applicability: Model Mystere-Falcon 50 

series airplanes, certificated in any category, 

serial numbers 222 to 286 inclusive, 288, 

290, and 291.

Note 1: This AD applies to each airplane 

identified in the preceding applicability 

provision, regardless of whether it has been 

modified, altered, or repaired in the area 

subject to the requirements of this AD. For 

airplanes that have been modified, altered, or 

repaired so that the performance of the 

requirements of this AD is affected, the 

owner/operator must request approval for an 

alternative method of compliance in 

accordance with paragraph (d) of this AD. 

The request should include an assessment of 

the effect of the modification, alteration, or 

repair on the unsafe condition addressed by 

this AD; and, if the unsafe condition has not 

been eliminated, the request should include 

specific proposed actions to address it.

Compliance: Required as indicated, unless 

accomplished previously. 

To prevent fuel leaks from the feeder tanks, 

which could result in fuel vapors in the cabin 

that could come into contact with ignition 

sources, accomplish the following: 

Leak Testing 

(a) Within 7 months after the effective date 

of this AD: Perform a feeder tank leak test by 

sampling at the drain ports of frames 29 and 

31, in accordance with Work Card No. 686.3/

1 of the Dassault Falcon 50 Maintenance 

Manual, Revision 7, dated August 2001. 

Repeat the leak test at intervals not to exceed 

13 months, until accomplishment of 

paragraph (c) of this AD. 

Corrective Action 

(b) If the feeder tank leak test indicates that 

a leak is present: Prior to further flight, renew 

the seal, in accordance with Work Card No. 

686.4/1 of the Dassault Falcon 50 

Maintenance Manual, Revision 7, dated 

August 2001. 

Modification 

(c) Within 78 months since the date of 

manufacture of the airplane: Rework the seals 

of the double-skin feeder tanks at frames 28 

and 31, in accordance with Dassault Service 

Bulletin F50–328, dated May 31, 2000. 

Accomplishment of the rework terminates 

the requirements of this AD. 

Alternative Methods of Compliance 

(d) An alternative method of compliance or 

adjustment of the compliance time that 

provides an acceptable level of safety may be 

used if approved by the Manager, 

International Branch, ANM–116, FAA. 

Operators shall submit their requests through 

an appropriate FAA Principal Maintenance 

Inspector, who may add comments and then 

send it to the Manager, International Branch, 

ANM–116.

Note 2: Information concerning the 

existence of approved alternative methods of 

compliance with this AD, if any, may be 

obtained from the Manager, International 

Branch, ANM–116.

Special Flight Permits 

(e) Special flight permits may be issued in 

accordance with sections 21.197 and 21.199 

of the Federal Aviation Regulations (14 CFR 

21.197 and 21.199) to operate the airplane to 

a location where the requirements of this AD 

can be accomplished.

Note 3: The subject of this AD is addressed 

in French airworthiness directive 2000–163–

030(B), dated April 19, 2000.

Issued in Renton, Washington, on 

December 26, 2001. 

Ali Bahrami, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service.

[FR Doc. 01–32194 Filed 12–31–01; 8:45 am] 

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. 2001–NM–209–AD] 

RIN 2120–AA64 

Airworthiness Directives; Boeing 

Model 767 Series Airplanes

AGENCY: Federal Aviation 

Administration, DOT.

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: This document proposes the 

adoption of a new airworthiness 

directive (AD) that is applicable to 

certain Boeing Model 767 series 

airplanes. This proposal would require 

an inspection of the tripod strut 

assembly of the inboard support of the 

leading edge slat of the wing for a 

preload condition, and follow-on 

actions. For certain airplanes, this 

proposal also would require inspection 

and replacement of the existing tripod 

struts with new, adjustable struts, if 

necessary. This action is necessary to 

prevent damage to the tripod strut 

assembly due to a preload condition, 

which could result in loss of control of 

the inboard leading edge slat or 

separation of the slat from the airplane, 

and consequent reduced controllability 

of the airplane. This action is intended 

to address the identified unsafe 

condition.

DATES: Comments must be received by 

February 19, 2002.

ADDRESSES: Submit comments in 

triplicate to the Federal Aviation 

Administration (FAA), Transport 

Airplane Directorate, ANM–114, 

Attention: Rules Docket No. 2001–NM–

209–AD, 1601 Lind Avenue, SW., 

Renton, Washington 98055–4056. 

Comments may be inspected at this 

location between 9:00 a.m. and 3:00 

p.m., Monday through Friday, except 

Federal holidays. Comments may be 

submitted via fax to (425) 227–1232. 

Comments may also be sent via the 

Internet using the following address: 9-

anm-nprmcomment@faa.gov. Comments 

sent via fax or the Internet must contain 

‘‘Docket No. 2001–NM–209–AD’’ in the 

subject line and need not be submitted 

in triplicate. Comments sent via the 

Internet as attached electronic files must 

be formatted in Microsoft Word 97 for 

Windows or ASCII text. 

The service information referenced in 

the proposed rule may be obtained from 

Boeing Commercial Airplane Group, 

P.O. Box 3707, Seattle, Washington 

98124–2207. This information may be 

examined at the FAA, Transport 

Airplane Directorate, 1601 Lind 

Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: John 

Craycraft, Aerospace Engineer, Airframe 

Branch, ANM–120S, FAA, Seattle 

Aircraft Certification Office, 1601 Lind 

Avenue, SW., Renton, Washington 

98055–4056; telephone (425) 227–2782; 

fax (425) 227–1181.

SUPPLEMENTARY INFORMATION: 

Comments Invited 

Interested persons are invited to 

participate in the making of the 

proposed rule by submitting such 

written data, views, or arguments as 

they may desire. Communications shall 

identify the Rules Docket number and 

be submitted in triplicate to the address 

specified above. All communications 

received on or before the closing date 

for comments, specified above, will be 

considered before taking action on the 

proposed rule. The proposals contained 

in this action may be changed in light 

of the comments received. 

Submit comments using the following 

format: 

• Organize comments issue-by-issue. 

For example, discuss a request to 

change the compliance time and a 

request to change the service bulletin 

reference as two separate issues. 

• For each issue, state what specific 

change to the proposed AD is being 

requested. 

36 Federal Register / Vol. 67, No. 1 / Wednesday, January 2, 2002 / Proposed Rules 

• Include justification (e.g., reasons or 

data) for each request. 

Comments are specifically invited on 

the overall regulatory, economic, 

environmental, and energy aspects of 

the proposed rule. All comments 

submitted will be available, both before 

and after the closing date for comments, 

in the Rules Docket for examination by 

interested persons. A report 

summarizing each FAA-public contact 

concerned with the substance of this 

proposal will be filed in the Rules 

Docket. 

Commenters wishing the FAA to 

acknowledge receipt of their comments 

submitted in response to this action 

must submit a self-addressed, stamped 

postcard on which the following 

statement is made: ‘‘Comments to 

Docket Number 2001–NM–209–AD.’’

The postcard will be date stamped and 

returned to the commenter. 

Availability of NPRMs 

Any person may obtain a copy of this 

NPRM by submitting a request to the 

FAA, Transport Airplane Directorate, 

ANM–114, Attention: Rules Docket No. 

2001–NM–209–AD, 1601 Lind Avenue, 

SW., Renton, Washington 98055–4056. 

Discussion 

The airplane manufacturer has 

informed the FAA that damaged 

bushings were found in the tripod strut 

assembly of the inboard support of the 

leading edge slat of the wings of a 

Model 767 series airplane in 

production. The damage was due to 

preload in the tripod assembly during 

installation. The tripod assembly is used 

to support the inboard leading edge slat 

and is the primary inboard-outboard 

load path of the slat. Loss of primary 

inboard-outboard load path for the slat 

can result in an unstable slat-to-wing 

connection, and separation of the slat 

from the airplane. Such conditions, if 

not corrected, could result in reduced 

controllability of the airplane. 

Explanation of Relevant Service 

Information 

The FAA has reviewed and approved 

Boeing Service Bulletin 767–57A0058, 

Revision 1, dated May 27, 1999, which 

describes procedures for a check 

(inspection) of the tripod strut assembly 

of the inboard support of the leading 

edge slat of the wing for a preload 

condition, and follow-on actions. The 

follow-on actions include: 

• If no preload condition is found, a 

visual inspection of the components in 

the fitting assembly to determine if 

bushing holes are round. 

• Replacement of the fitting assembly 

if the bushing holes are not round. 

• If a preload condition is found, a 

high frequency eddy current inspection 

of the lug bore and base of the fitting 

assembly for cracking. 

• Rework of the fitting assembly if no 

cracking is found, or if cracking is found 

in the lug bore only. 

• Replacement of the fitting assembly 

if cracking is found in the lug base or 

the lug bore and base. 

• Adjustment of the tripod struts, if 

necessary, to eliminate preload 

condition, and a check of the rigging of 

the inboard leading edge slat, and rerigging if necessary. 

• For certain airplanes, inspection for 

improperly cut and spliced struts, and 

strut replacement, if necessary. 

The FAA also has reviewed and 

approved Boeing Service Bulletin 767–

57–0037, dated January 14, 1993. For 

Group 2 airplanes (as defined in the 

service bulletin) the service bulletin 

describes procedures for doing a visual 

inspection of the tripod struts of the 

inboard leading edge of the wings to 

determine if they have been cut and 

spliced, and replacement with new, 

adjustable struts if the existing struts are 

cut and spliced with fewer than six hiloks. 

Accomplishment of the actions 

specified in the service bulletins is 

intended to adequately address the 

identified unsafe condition. 

Explanation of Requirements of 

Proposed Rule 

Since an unsafe condition has been 

identified that is likely to exist or 

develop on other products of this same 

type design, the proposed AD would 

require accomplishment of certain 

actions specified in the service bulletins 

described previously, except as 

discussed below. 

Differences Between This Proposed AD 

and the Service Bulletins 

The service bulletins do not specify 

what type of visual inspection of the 

tripod assembly and tripod struts 

should be used. The FAA has 

determined that the procedures in the 

service bulletins describe a general 

visual inspection. Note 2 of this 

proposed AD defines that type of 

inspection. 

Other differences include the 

following: 

• Boeing Service Bulletin 767–

57A0058, Revision 1, specifies doing a 

‘‘check’’ for preload, however, this 

proposed AD uses the term ‘‘general 

visual inspection.’’

• The compliance time for doing the 

actions specified in the Boeing Service 

Bulletin 767–57A0058, Revision 1, is 

within 5,000 flight cycles or 24 months 

after the receipt of the service bulletin, 

whichever comes first. The airplane 

manufacturer has informed us that 

‘‘whichever comes first’’ is an error in 

the compliance time and would put 

certain airplanes immediately out of 

compliance. The correct compliance 

time is ‘‘whichever comes later,’’ and 

this proposed AD requires that 

compliance time. 

• The effectivity in Boeing Service 

Bulletin 767–57–0037 specifies line 

numbers 1 through 469 inclusive. The 

airplane manufacturer has informed us 

that line numbers 1 through 159 

inclusive had a fixed strut which was 

not cut and spliced or preloaded. Line 

numbers 160 through 469 inclusive may 

have had a fixed strut which was cut 

and spliced, and if it was not cut and 

spliced it was still subject to being 

preloaded. Therefore, the affected line 

numbers are 160 through 469 inclusive, 

and those line numbers are included in 

this proposed AD. 

Cost Impact 

There are approximately 379 

airplanes of the affected design in the 

worldwide fleet. The FAA estimates that 

136 airplanes of U.S. registry would be 

affected by this proposed AD. 

It would take approximately 1 work 

hour per airplane to accomplish the 

proposed inspections of the tripod strut 

assembly and bushing holes, at an 

average labor rate of $60 per work hour. 

Based on these figures, the cost impact 

of the inspections proposed by this AD 

on U.S. operators is estimated to be 

$8,160, or $60 per airplane. 

The cost impact figure discussed 

above is based on assumptions that no 

operator has yet accomplished any of 

the proposed requirements of this AD 

action, and that no operator would 

accomplish those actions in the future if 

this proposed AD were not adopted. The 

cost impact figures discussed in AD 

rulemaking actions represent only the 

time necessary to perform the specific 

actions actually required by the AD. 

These figures typically do not include 

incidental costs, such as the time 

required to gain access and close up, 

planning time, or time necessitated by 

other administrative actions. 

Should an operator be required to 

accomplish the rework of the fitting 

assembly, it would take approximately 4 

work hours per airplane to accomplish 

the proposed rework, at an average labor 

rate of $60 per work hour. Based on 

these figures, the cost impact of the 

proposed rework would be $240 per 

airplane. 

Should an operator be required to 

accomplish the high frequency eddy 

current inspection, it would take 

Federal Register / Vol. 67, No. 1 / Wednesday, January 2, 2002 / Proposed Rules 37

approximately 5 work hours per 

airplane to accomplish the proposed 

inspection, at an average labor rate of 

$60 per work hour. Based on these 

figures, the cost impact of the proposed 

inspection would be $300 per airplane. 

Should an operator be required to 

accomplish the replacement of the main 

strut support fitting, it would take 

approximately 14 work hours per 

airplane to accomplish the proposed 

replacement (on both the left and right 

wings of the airplane, excluding the 

time for gaining access and closing up), 

at an average labor rate of $60 per work 

hour. 

Required parts would cost 

approximately $12,380 per airplane. 

Based on these figures, the cost impact 

of the proposed replacement would be 

$13,220 per airplane. 

Should an operator be required to 

accomplish the inspection for 

improperly cut and spliced struts, it 

would take approximately 1 work hour 

per airplane to accomplish the proposed 

inspection, at an average labor rate of 

$60 per work hour. Based on these 

figures, the cost impact of the inspection 

of the struts proposed by this AD would 

be $60 per airplane. 

Should an operator be required to 

accomplish the replacement of a cut and 

spliced strut with a new, adjustable 

tripod strut, it would take 

approximately 4 work hours per 

airplane to accomplish the proposed 

replacement, at an average labor rate of 

$60 per work hour. Based on these 

figures, the cost impact of the 

replacement proposed by this AD would 

be $240 per airplane. 

Regulatory Impact 

The regulations proposed herein 

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. Therefore, 

it is determined that this proposal 

would not have federalism implications 

under Executive Order 13132. 

For the reasons discussed above, I 

certify that 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) if 

promulgated, 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. A copy of the draft 

regulatory evaluation prepared for this 

action is contained in the Rules Docket. 

A copy of it may be obtained by 

contacting the Rules Docket at the 

location provided under the caption 

ADDRESSES.

List of Subjects in 14 CFR Part 39 

Air transportation, Aircraft, Aviation 

safety, Safety.

The Proposed Amendment 

Accordingly, pursuant to the 

authority delegated to me by the 

Administrator, the Federal Aviation 

Administration proposes to amend part 

39 of the Federal Aviation Regulations 

(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. Section 39.13 is amended by 

adding the following new airworthiness 

directive:

Boeing: Docket 2001–NM–209–AD.

Applicability: Model 767 series airplanes, 

line numbers 160 through 541 inclusive, 

certificated in any category.

Note 1: This AD applies to each airplane 

identified in the preceding applicability 

provision, regardless of whether it has been 

modified, altered, or repaired in the area 

subject to the requirements of this AD. For 

airplanes that have been modified, altered, or 

repaired so that the performance of the 

requirements of this AD is affected, the 

owner/operator must request approval for an 

alternative method of compliance in 

accordance with paragraph (e) of this AD. 

The request should include an assessment of 

the effect of the modification, alteration, or 

repair on the unsafe condition addressed by 

this AD; and, if the unsafe condition has not 

been eliminated, the request should include 

specific proposed actions to address it.

Compliance: Required as indicated, unless 

accomplished previously. 

To prevent damage to the tripod strut 

assembly due to a preload condition, which 

could result in loss of control of the inboard 

leading edge slat or separation of the slat 

from the airplane, and consequent reduced 

controllability of the airplane, accomplish 

the following: 

Inspections 

(a) For all airplanes: Before the 

accumulation of 5,000 total flight cycles or 

within 24 months after the effective date of 

this AD, whichever is later: Do a general 

visual inspection (check) of the tripod strut 

assembly of the inboard leading edge slat of 

each wing for a preload condition, per Figure 

2 of Boeing Service Bulletin 767–57A0058, 

Revision 1, dated May 27, 1999.

Note 2: For the purposes of this AD, a 

general visual inspection is defined as: ‘‘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 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.’’

(1) If no preload condition is found, before 

further flight, inspect the fitting assembly 

bushing holes for roundness, per Figure 5 of 

the Accomplishment Instructions of the 

service bulletin. 

(i) If all the bushing holes are round, before 

further flight, do the inspection required by 

paragraph (c) of this AD. 

(ii) If any bushing hole is not round, before 

further flight, do the inspections required by 

paragraphs (b) and (c) of this AD. 

(2) If a preload condition is found, before 

further flight, do the inspections required by 

paragraphs (b) and (c) of this AD. 

Follow-on Actions 

(b) For airplanes subject to paragraph 

(a)(1)(ii) or (a)(2) of this AD: Do a high 

frequency eddy current inspection of the 

fitting assembly lug for cracking, per Figure 

6 of the Accomplishment Instructions of 

Boeing Service Bulletin 767–57A0058, 

Revision 1, dated May 27, 1999. 

(1) If no cracking is found, or if cracking 

is found in the lug bore only, before further 

flight, rework the fitting assembly lug per 

Figure 7 of the Accomplishment Instructions 

of the service bulletin. 

(2) If cracking is found in the fitting lug 

base or the lug bore and base, before further 

flight, purge the auxiliary fuel tank and 

replace the fitting assembly lug per Figure 8 

of the Accomplishment Instructions of the 

service bulletin. 

(c) For airplanes subject to paragraph 

(a)(1)(i), (a)(1)(ii), or (a)(2) of this AD: Do a 

general visual inspection of the bushing 

holes of the main strut assembly to determine 

if the bushing holes are round, per Figure 9 

of the Accomplishment Instructions of 

Boeing Service Bulletin 767–57A0058, 

Revision 1, dated May 27, 1999. 

(1) If the bushing holes are round, before 

further flight, assemble the tripod assembly 

per Figure 11 or Figure 12, as applicable, of 

the Accomplishment Instructions of the 

service bulletin. 

(2) If the bushing holes are not round, 

before further flight, replace the main strut 

fitting assembly per Figure 10 of the 

Accomplishment Instructions of the service 

bulletin, then assemble the tripod assembly 

per Figure 11 or Figure 12, as applicable, of 

the Accomplishment Instructions of the 

service bulletin.

Note 3: Inspections and follow-on actions 

done before the effective date of this AD per 

Boeing Alert Service Bulletin 767–57A0058, 

dated June 11, 1998, are considered 

acceptable for compliance with the 

applicable actions specified in this AD.

Inspection/Replacement of Tripod Struts 

(d) For Group 2 airplanes that have not 

accomplished Boeing Service Bulletin 767–

57–0037, dated January 14, 1993: Before 

further flight after doing the inspections and 

follow-on actions required by paragraphs (a), 

38 Federal Register / Vol. 67, No. 1 / Wednesday, January 2, 2002 / Proposed Rules 

(b), and (c) of this AD, do a general visual 

inspection of the tripod struts to determine 

if they have been cut and spliced, per the 

Accomplishment Instructions of the service 

bulletin. 

(1) If the tripod struts have been cut and 

spliced with fewer than six hi-loks, before 

further flight, replace with new, adjustable 

struts, per Figure 1 of the Accomplishment 

Instructions of the service bulletin. 

(2) If the tripod struts have not been cut 

and spliced, or they have been cut and 

spliced with six hi-loks, no further action is 

required by this paragraph. 

Alternative Methods of Compliance 

(e) An alternative method of compliance or 

adjustment of the compliance time that 

provides an acceptable level of safety may be 

used if approved by the Manager, Seattle 

Aircraft Certification Office (ACO), FAA. 

Operators shall submit their requests through 

an appropriate FAA Principal Maintenance 

Inspector, who may add comments and then 

send it to the Manager, Seattle ACO.

Note 4: Information concerning the 

existence of approved alternative methods of 

compliance with this AD, if any, may be 

obtained from the Seattle ACO.

Special Flight Permit 

(f) Special flight permits may be issued in 

accordance with sections 21.197 and 21.199 

of the Federal Aviation Regulations (14 CFR 

21.197 and 21.199) to operate the airplane to 

a location where the requirements of this AD 

can be accomplished.

Issued in Renton, Washington, on 

December 26, 2001. 

Ali Bahrami, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service.

[FR Doc. 01–32195 Filed 12–31–01; 8:45 am] 

BILLING CODE 4910–39–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. 2001–NM–34–AD] 

RIN 2120–AA64 

Airworthiness Directives; Boeing 

Model 747–100, 747–100B, 747–100B 

SUD, 747–200B, 747–200F, 747–300, 

747SP, and 747SR Series Airplanes

AGENCY: Federal Aviation 

Administration, DOT.

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: This document proposes the 

adoption of a new airworthiness 

directive (AD) that is applicable to 

certain Boeing Model 747–100, 747–

100B, 747–100B SUD, 747–200B, 747–

200F, 747–300, 747SP, and 747SR series 

airplanes. This proposal would require 

one-time inspections for cracking in 

certain upper deck floor beams and 

follow-on actions. This action is 

necessary to find and fix cracking in 

certain upper deck floor beams. Such 

cracking could extend and sever floor 

beams adjacent to the body frame and 

result in rapid depressurization of the 

airplane. This action is intended to 

address the identified unsafe condition.

DATES: Comments must be received by 

February 19, 2002.

ADDRESSES: Submit comments in 

triplicate to the Federal Aviation 

Administration (FAA), Transport 

Airplane Directorate, ANM–114, 

Attention: Rules Docket No. 2001–NM–

34–AD, 1601 Lind Avenue, SW., 

Renton, Washington 98055–4056. 

Comments may be inspected at this 

location between 9:00 a.m. and 3:00 

p.m., Monday through Friday, except 

Federal holidays. Comments may be 

submitted via fax to (425) 227–1232. 

Comments may also be sent via the 

Internet using the following address: 9-

anm-nprmcomment@faa.gov. Comments 

sent via fax or the Internet must contain 

‘‘Docket No. 2001–NM–34–AD’’ in the 

subject line and need not be submitted 

in triplicate. Comments sent via the 

Internet as attached electronic files must 

be formatted in Microsoft Word 97 for 

Windows or ASCII text. 

The service information referenced in 

the proposed rule may be obtained from 

Boeing Commercial Airplane Group, 

P.O. Box 3707, Seattle, Washington 

98124–2207. This information may be 

examined at the FAA, Transport 

Airplane Directorate, 1601 Lind 

Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Rick 

Kawaguchi, Aerospace Engineer, 

Airframe Branch, ANM–120S, FAA, 

Seattle Aircraft Certification Office, 

1601 Lind Avenue, SW., Renton, 

Washington 98055–4056; telephone 

(425) 227–1153; fax (425) 227–1181.

SUPPLEMENTARY INFORMATION: 

Comments Invited 

Interested persons are invited to 

participate in the making of the 

proposed rule by submitting such 

written data, views, or arguments as 

they may desire. Communications shall 

identify the Rules Docket number and 

be submitted in triplicate to the address 

specified above. All communications 

received on or before the closing date 

for comments, specified above, will be 

considered before taking action on the 

proposed rule. The proposals contained 

in this action may be changed in light 

of the comments received. 

Submit comments using the following 

format: 

• Organize comments issue-by-issue. 

For example, discuss a request to 

change the compliance time and a 

request to change the service bulletin 

reference as two separate issues. 

• For each issue, state what specific 

change to the proposed AD is being 

requested. 

• Include justification (e.g., reasons or 

data) for each request. 

Comments are specifically invited on 

the overall regulatory, economic, 

environmental, and energy aspects of 

the proposed rule. All comments 

submitted will be available, both before 

and after the closing date for comments, 

in the Rules Docket for examination by 

interested persons. A report 

summarizing each FAA-public contact 

concerned with the substance of this 

proposal will be filed in the Rules 

Docket. 

Commenters wishing the FAA to 

acknowledge receipt of their comments 

submitted in response to this action 

must submit a self-addressed, stamped 

postcard on which the following 

statement is made: ‘‘Comments to 

Docket Number 2001–NM–34–AD.’’ The 

postcard will be date-stamped and 

returned to the commenter. 

Availability of NPRMs 

Any person may obtain a copy of this 

NPRM by submitting a request to the 

FAA, Transport Airplane Directorate, 

ANM–114, Attention: Rules Docket No. 

2001–NM–34–AD, 1601 Lind Avenue, 

SW., Renton, Washington 98055–4056. 

Discussion 

The FAA has received reports of 

fatigue cracking on the left and right 

ends of the upper chord of the station 

(STA) 340 upper deck floor beam on 

several Boeing Model 747 series 

airplanes. Also, during fatigue tests on 

a Boeing 747SR test airplane, multiple 

cracks up to 0.3 inch long were found 

in both the left and right ends of the 

upper chord of the STA 340 floor beam. 

On certain Boeing Model 747–100, 747–

100B, 747–100B SUD, 747–200B, 747–

200F, 747–300, 747SP, and 747SR series 

airplanes, the STA 340 upper deck floor 

beam, as well as the floor beam at STA 

360, are made from 7075 aluminum. 

Other upper deck floor beams on these 

models are made from 2024 aluminum, 

which is known to be more durable than 

7075 aluminum against fatigue. 

Cracking of the upper deck floor beam 

at STA 340 or STA 360, if not corrected, 

could extend and sever floor beams 

adjacent to the body frame and result in 

rapid depressurization of the airplane.